diff --git a/src/builtins.ts b/src/builtins.ts
index e9f563e1e6..6a4a8de1e5 100644
--- a/src/builtins.ts
+++ b/src/builtins.ts
@@ -43,7 +43,8 @@ import {
   NodeKind,
   LiteralExpression,
   ArrayLiteralExpression,
-  IdentifierExpression
+  IdentifierExpression,
+  FunctionExpression
 } from "./ast";
 
 import {
@@ -194,6 +195,8 @@ export namespace BuiltinNames {
   export const instantiate = "~lib/builtins/instantiate";
   export const idof = "~lib/builtins/idof";
 
+  export const experimental_first_class_function = "~lib/builtins/experimental_first_class_function";
+
   export const i8 = "~lib/builtins/i8";
   export const i16 = "~lib/builtins/i16";
   export const i32 = "~lib/builtins/i32";
@@ -3609,6 +3612,26 @@ function builtin_unchecked(ctx: BuiltinFunctionContext): ExpressionRef {
 }
 builtinFunctions.set(BuiltinNames.unchecked, builtin_unchecked);
 
+// experimental_first_class_function(FunctionExpression: *) -> *
+function builtin_experimental_first_class_function(ctx: BuiltinFunctionContext): ExpressionRef {
+  let compiler = ctx.compiler;
+  let module = compiler.module;
+  if (
+    checkTypeAbsent(ctx) |
+    checkArgsRequired(ctx, 1)
+  ) return module.unreachable();
+  let operand = ctx.operands[0];
+  if (operand.kind != NodeKind.Function) {
+    let prototype = ctx.prototype;
+    prototype.program.error(DiagnosticCode._0_expected, operand.range, "FunctionExpression");
+    return module.unreachable();
+  }
+  let functionExpression = <FunctionExpression>operand;
+  let expr = compiler.compileFirstClassFunction(functionExpression);
+  return expr;
+}
+builtinFunctions.set(BuiltinNames.experimental_first_class_function, builtin_experimental_first_class_function);
+
 // call_indirect<T?>(index: u32, ...args: *[]) -> T
 function builtin_call_indirect(ctx: BuiltinFunctionContext): ExpressionRef {
   let compiler = ctx.compiler;
@@ -10668,11 +10691,11 @@ export function compileVisitGlobals(compiler: Compiler): void {
     let global = <Global>element;
     let globalType = global.type;
     let classReference = globalType.getClass();
-    if (
-      classReference &&
-      !classReference.hasDecorator(DecoratorFlags.Unmanaged) &&
-      global.is(CommonFlags.Compiled)
-    ) {
+    let signatureReference = globalType.getSignature();
+    let isGcObject =
+      (classReference != null && !classReference.hasDecorator(DecoratorFlags.Unmanaged)) ||
+      (signatureReference != null && signatureReference.hasEnv);
+    if (isGcObject && global.is(CommonFlags.Compiled)) {
       if (global.is(CommonFlags.Inlined)) {
         let value = global.constantIntegerValue;
         if (i64_low(value) || i64_high(value)) {
diff --git a/src/common.ts b/src/common.ts
index f5d6675edd..fcdfcce8cd 100644
--- a/src/common.ts
+++ b/src/common.ts
@@ -158,6 +158,7 @@ export namespace CommonNames {
   export const valueof = "valueof";
   export const returnof = "returnof";
   export const nonnull = "nonnull";
+  export const experimental_first_class_function = "experimental_first_class_function";
   // aliases
   export const null_ = "null";
   export const true_ = "true";
@@ -225,6 +226,7 @@ export namespace CommonNames {
   export const Set = "Set";
   export const Map = "Map";
   export const Function = "Function";
+  export const FirstClassFunction = "FirstClassFunctionBase";
   export const ArrayBufferView = "ArrayBufferView";
   export const ArrayBuffer = "ArrayBuffer";
   export const Math = "Math";
diff --git a/src/compiler.ts b/src/compiler.ts
index 6508090626..53a38fd7b0 100644
--- a/src/compiler.ts
+++ b/src/compiler.ts
@@ -188,7 +188,8 @@ import {
   TypeKind,
   TypeFlags,
   Signature,
-  typesToRefs
+  typesToRefs,
+  SignatureFlags
 } from "./types";
 
 import {
@@ -2054,20 +2055,23 @@ export class Compiler extends DiagnosticEmitter {
 
   // === Table ====================================================================================
 
+  private registerFunctionInTable(instance: Function): u32 {
+    // Add to the function table
+    let functionTable = this.functionTable;
+    let tableBase = this.options.tableBase;
+    if (!tableBase) tableBase = 1; // leave first elem blank
+    let index = tableBase + functionTable.length;
+    functionTable.push(instance);
+    return index;
+  }
+
   /** Ensures that a runtime counterpart of the specified function exists and returns its address. */
   ensureRuntimeFunction(instance: Function): i64 {
     assert(instance.is(CommonFlags.Compiled) && !instance.is(CommonFlags.Stub));
     let program = this.program;
     let memorySegment = instance.memorySegment;
     if (!memorySegment) {
-
-      // Add to the function table
-      let functionTable = this.functionTable;
-      let tableBase = this.options.tableBase;
-      if (!tableBase) tableBase = 1; // leave first elem blank
-      let index = tableBase + functionTable.length;
-      functionTable.push(instance);
-
+      let index = this.registerFunctionInTable(instance);
       // Create runtime function
       let rtInstance = assert(this.resolver.resolveClass(program.functionPrototype, [ instance.type ]));
       let buf = rtInstance.createBuffer();
@@ -6085,12 +6089,13 @@ export class Compiler extends DiagnosticEmitter {
     let functionArg = this.compileExpression(expression.expression, Type.auto);
     let signature = this.currentType.getSignature();
     if (signature) {
+      const thisArg = signature.hasEnv ? functionArg : 0;
       return this.compileCallIndirect(
         signature,
         functionArg,
         expression.args,
         expression,
-        0,
+        thisArg,
         contextualType == Type.void
       );
     }
@@ -7038,6 +7043,38 @@ export class Compiler extends DiagnosticEmitter {
     return module.unreachable();
   }
 
+  compileFirstClassFunction(
+    expression: FunctionExpression
+  ): ExpressionRef {
+    let module = this.module;
+    let flow = this.currentFlow;
+    let sourceFunction = flow.sourceFunction;
+    let declaration = expression.declaration.clone();
+    let anonymousId = sourceFunction.nextAnonymousId++;
+    let contextualTypeArguments = cloneMap(flow.contextualTypeArguments);
+
+    let prototype = new FunctionPrototype(
+      `${sourceFunction.internalName}|anonymous|${anonymousId}`,
+      sourceFunction,
+      declaration
+    );
+    let instance = this.resolver.resolveFirstClassFunction(prototype, contextualTypeArguments, ReportMode.Report);
+    if (!instance) return this.module.unreachable();
+    instance.flow.outer = flow;
+
+    let worked = this.compileFunction(instance);
+    this.currentType = instance.signature.type;
+    if (!worked) return module.unreachable();
+
+    const currentType = this.currentType;
+    if (!instance) return module.unreachable(); 
+    const functionIndexInTable = this.registerFunctionInTable(instance);
+    let ctor = this.ensureConstructor(this.program.firstClassFunctionInstance, expression);
+    let expr = this.makeCallDirect(ctor, [module.i32(0), module.i32(functionIndexInTable), module.usize(0)], expression, /* immediatelyDropped */ false);
+    this.currentType = currentType;
+    return expr;
+  }
+
   private compileFunctionExpression(
     expression: FunctionExpression,
     contextualType: Type,
@@ -8774,7 +8811,7 @@ export class Compiler extends DiagnosticEmitter {
             classInstance.type,
             classInstance.type,
             baseCtor.signature.requiredParameters,
-            baseCtor.signature.hasRest
+            baseCtor.signature.hasRest ? SignatureFlags.Rest : SignatureFlags.None
           ),
           contextualTypeArguments
         );
diff --git a/src/program.ts b/src/program.ts
index 1f9849eec2..1dea69360d 100644
--- a/src/program.ts
+++ b/src/program.ts
@@ -538,6 +538,14 @@ export class Program extends DiagnosticEmitter {
   }
   private _functionPrototype: ClassPrototype | null = null;
 
+  /** Get the first class `Function` instance */
+  get firstClassFunctionInstance(): Class {
+    let cached = this._firstClassFunctionInstance;
+    if (!cached) this._firstClassFunctionInstance = cached = this.requireClass(CommonNames.FirstClassFunction);
+    return cached;
+  }
+  private _firstClassFunctionInstance: Class | null = null;
+
   /** Gets the standard `Int8Array` prototype. */
   get int8ArrayPrototype(): ClassPrototype {
     let cached = this._int8ArrayPrototype;
@@ -1010,6 +1018,12 @@ export class Program extends DiagnosticEmitter {
       this.makeNativeTypeDeclaration(CommonNames.nonnull, CommonFlags.Export | CommonFlags.Generic),
       DecoratorFlags.Builtin
     ));
+    this.nativeFile.add(CommonNames.experimental_first_class_function, new TypeDefinition(
+      CommonNames.experimental_first_class_function,
+      this.nativeFile,
+      this.makeNativeTypeDeclaration(CommonNames.experimental_first_class_function, CommonFlags.Export | CommonFlags.Generic),
+      DecoratorFlags.Builtin
+    ));
 
     // The following types might not be enabled by compiler options, so the
     // compiler needs to check this condition whenever such a value is created
@@ -3741,7 +3755,6 @@ export class FunctionPrototype extends DeclaredElement {
 
 /** A resolved function. */
 export class Function extends TypedElement {
-
   /** Function prototype. */
   prototype: FunctionPrototype;
   /** Function signature. */
diff --git a/src/resolver.ts b/src/resolver.ts
index ca05a3424b..6e7c25e74c 100644
--- a/src/resolver.ts
+++ b/src/resolver.ts
@@ -36,7 +36,7 @@ import {
   IndexSignature,
   isTypedElement,
   InterfacePrototype,
-  DeclaredElement
+  DeclaredElement,
 } from "./program";
 
 import {
@@ -84,7 +84,8 @@ import {
   Signature,
   typesToString,
   TypeKind,
-  TypeFlags
+  TypeFlags,
+  SignatureFlags,
 } from "./types";
 
 import {
@@ -309,6 +310,9 @@ export class Resolver extends DiagnosticEmitter {
         if (text == CommonNames.valueof)  return this.resolveBuiltinValueofType(node, ctxElement, ctxTypes, reportMode);
         if (text == CommonNames.returnof) return this.resolveBuiltinReturnTypeType(node, ctxElement, ctxTypes, reportMode);
         if (text == CommonNames.nonnull)  return this.resolveBuiltinNotNullableType(node, ctxElement, ctxTypes, reportMode);
+        if (text == CommonNames.experimental_first_class_function) {
+          return this.resolveBuiltinFirstClassFunctionType(node, ctxElement, ctxTypes, reportMode);
+        }
       }
 
       // Resolve normally
@@ -383,7 +387,7 @@ export class Resolver extends DiagnosticEmitter {
     let numParameters = parameterNodes.length;
     let parameterTypes = new Array<Type>(numParameters);
     let requiredParameters = 0;
-    let hasRest = false;
+    let flags = SignatureFlags.None;
     for (let i = 0; i < numParameters; ++i) {
       let parameterNode = parameterNodes[i];
       switch (parameterNode.parameterKind) {
@@ -393,7 +397,7 @@ export class Resolver extends DiagnosticEmitter {
         }
         case ParameterKind.Rest: {
           assert(i == numParameters - 1);
-          hasRest = true;
+          flags |= SignatureFlags.Rest;
           break;
         }
       }
@@ -435,7 +439,67 @@ export class Resolver extends DiagnosticEmitter {
       );
       if (!returnType) return null;
     }
-    let signature = Signature.create(this.program, parameterTypes, returnType, thisType, requiredParameters, hasRest);
+    let signature = Signature.create(this.program, parameterTypes, returnType, thisType, requiredParameters, flags);
+    return node.isNullable ? signature.type.asNullable() : signature.type;
+  }
+
+  /** Resolves a {@link FunctionTypeNode} to a concrete {@link Type}. */
+  private resolveFirstClassFunctionType(
+    /** The type to resolve. */
+    node: FunctionTypeNode,
+    /** Contextual element. */
+    ctxElement: Element,
+    /** Contextual types, i.e. `T`. */
+    ctxTypes: Map<string,Type> | null = null,
+    /** How to proceed with eventual diagnostics. */
+    reportMode: ReportMode = ReportMode.Report
+  ): Type | null {
+    const explicitThisType = node.explicitThisType;
+    if (explicitThisType) {
+      if (reportMode == ReportMode.Report) {
+        this.error(DiagnosticCode.Not_implemented_0, explicitThisType.range, "first class with this");
+      }
+      return null;
+    }
+
+    const parameterNodes = node.parameters;
+    const numParameters = parameterNodes.length;
+    let parameterTypes = new Array<Type>(numParameters);
+    for (let i = 0; i < numParameters; ++i) {
+      let parameterNode = parameterNodes[i];
+      switch (parameterNode.parameterKind) {
+        case ParameterKind.Default:
+          break;
+        case ParameterKind.Rest:
+          if (reportMode == ReportMode.Report) {
+            this.error(DiagnosticCode.Not_implemented_0, parameterNode.range, "first class with rest parameter");
+          }
+          return null;
+      }
+      let parameterTypeNode = parameterNode.type;
+      if (isTypeOmitted(parameterTypeNode)) {
+        if (reportMode == ReportMode.Report) {
+          this.error(DiagnosticCode.Type_expected, parameterTypeNode.range);
+        }
+        return null;
+      }
+      let parameterType = this.resolveType(parameterTypeNode, ctxElement, ctxTypes, ReportMode.Report);
+      if (!parameterType) return null;
+      parameterTypes[i] = parameterType;
+    }
+    let returnTypeNode = node.returnType;
+    let returnType: Type | null;
+    if (isTypeOmitted(returnTypeNode)) {
+      if (reportMode == ReportMode.Report) {
+        this.error(DiagnosticCode.Type_expected, returnTypeNode.range);
+      }
+      returnType = Type.void;
+    } else {
+      returnType = this.resolveType(returnTypeNode, ctxElement, ctxTypes, ReportMode.Report);
+      if (!returnType) return null;
+    }
+    let thisType = this.program.firstClassFunctionInstance.type;
+    let signature = Signature.create(this.program, parameterTypes, returnType, thisType, numParameters, SignatureFlags.Env);
     return node.isNullable ? signature.type.asNullable() : signature.type;
   }
 
@@ -589,6 +653,28 @@ export class Resolver extends DiagnosticEmitter {
     return typeArgument.nonNullableType;
   }
 
+  private resolveBuiltinFirstClassFunctionType(
+    /** The type to resolve. */
+    node: NamedTypeNode,
+    /** Contextual element. */
+    ctxElement: Element,
+    /** Contextual types, i.e. `T`. */
+    ctxTypes: Map<string,Type> | null = null,
+    /** How to proceed with eventual diagnostics. */
+    reportMode: ReportMode = ReportMode.Report
+  ): Type | null {
+    const typeArgumentNode = this.ensureOneTypeArgument(node, reportMode);
+    if (!typeArgumentNode) return null;
+    if (typeArgumentNode.kind != NodeKind.FunctionType) {
+      return null; // FIXME
+    }
+    let typeArgument = this.resolveFirstClassFunctionType(<FunctionTypeNode>typeArgumentNode, ctxElement, ctxTypes, reportMode);
+    if (!typeArgument) return null;
+    let signature = typeArgument.getSignature();
+    if (!signature) return null;
+    return typeArgument;
+  }
+
   /** Resolves a type name to the program element it refers to. */
   resolveTypeName(
     /** The type name to resolve. */
@@ -2761,7 +2847,7 @@ export class Resolver extends DiagnosticEmitter {
           type,
           signatureReference.thisType,
           signatureReference.requiredParameters,
-          signatureReference.hasRest,
+          signatureReference.flags,
         );
       }
     }
@@ -3044,6 +3130,91 @@ export class Resolver extends DiagnosticEmitter {
     );
   }
 
+  /** Resolves a function prototype using the specified concrete type arguments. */
+  resolveFirstClassFunction(
+    /** The prototype of the function. */
+    prototype: FunctionPrototype,
+    /** Contextual types, i.e. `T`. */
+    ctxTypes: Map<string,Type> = new Map(),
+    /** How to proceed with eventual diagnostics. */
+    reportMode: ReportMode = ReportMode.Report
+  ): Function | null {
+    let signatureNode = prototype.functionTypeNode;
+    let parent = prototype.parent;
+    let name = prototype.name;
+
+    let classInstance = this.program.firstClassFunctionInstance;
+
+    let explicitThisType = signatureNode.explicitThisType;
+    if (explicitThisType) {
+      if (reportMode == ReportMode.Report) {
+        this.error(DiagnosticCode.Not_implemented_0, explicitThisType.range, "first class with this");
+      }
+      return null;
+    }
+    let envType = classInstance.type;
+
+    // resolve parameter types
+    let signatureParameters = signatureNode.parameters;
+    let numSignatureParameters = signatureParameters.length;
+    let parameterTypes = new Array<Type>(numSignatureParameters);
+    for (let i = 0; i < numSignatureParameters; ++i) {
+      let parameterDeclaration = signatureParameters[i];
+      if (parameterDeclaration.parameterKind == ParameterKind.Default) {
+        if (reportMode == ReportMode.Report) {
+          this.error(DiagnosticCode.Not_implemented_0, parameterDeclaration.range, "first class with default parameter");
+        }
+      }
+      let typeNode = parameterDeclaration.type;
+      if (isTypeOmitted(typeNode)) {
+        if (reportMode == ReportMode.Report) {
+          this.error(DiagnosticCode.Type_expected, typeNode.range);
+        }
+        return null;
+      }
+      let parameterType = this.resolveType(
+        typeNode,
+        parent, // relative to function
+        ctxTypes,
+        reportMode
+      );
+      if (!parameterType) return null;
+      if (parameterType == Type.void) {
+        if (reportMode == ReportMode.Report) {
+          this.error(DiagnosticCode.Type_expected, typeNode.range);
+        }
+        return null;
+      }
+      parameterTypes[i] = parameterType;
+    }
+
+    // resolve return type
+    let typeNode = signatureNode.returnType;
+    if (isTypeOmitted(typeNode)) {
+      if (reportMode == ReportMode.Report) {
+        this.error(DiagnosticCode.Type_expected, typeNode.range);
+      }
+      return null;
+    }
+    let returnType = this.resolveType(
+      typeNode,
+      parent, // relative to function
+      ctxTypes,
+      reportMode
+    );
+    if (!returnType) return null;
+
+    let signature = Signature.create(this.program, parameterTypes, returnType, envType, numSignatureParameters, SignatureFlags.Env);
+    let instance = new Function(
+      name,
+      prototype,
+      null,
+      signature,
+      ctxTypes
+    );
+    return instance;
+  }
+
   /** Resolves reachable overrides of the given instance method. */
   resolveOverrides(instance: Function): Function[] | null {
     let overridePrototypes = instance.prototype.unboundOverrides;
diff --git a/src/types.ts b/src/types.ts
index f137ddb5ba..a0f1e7e98d 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -926,6 +926,14 @@ export function typesToString(types: Type[]): string {
   return sb.join(",");
 }
 
+export enum SignatureFlags {
+  None = 0,
+  /** rest parameters */
+  Rest = 1 << 0,
+  /** first-class function, this argument */
+  Env = 1 << 1,
+}
+
 /** Represents a fully resolved function signature. */
 export class Signature {
   /** Construct a new signature. */
@@ -940,8 +948,8 @@ export class Signature {
     thisType: Type | null = null,
     /** Number of required parameters excluding `this`. Other parameters are considered optional. */
     requiredParameters: i32 = parameterTypes ? parameterTypes.length : 0,
-    /** Whether the last parameter is a rest parameter. */
-    hasRest: bool = false,
+    /** signature flags */
+    flags: SignatureFlags = SignatureFlags.None,
   ): Signature {
     // get the usize type, and the type of the signature
     let usizeType = program.options.usizeType;
@@ -956,7 +964,7 @@ export class Signature {
     let nextId = program.nextSignatureId;
     
     // construct the signature and calculate it's unique key
-    let signature = new Signature(program, parameterTypes, returnType, thisType, requiredParameters, hasRest, nextId, type);
+    let signature = new Signature(program, parameterTypes, returnType, thisType, requiredParameters, flags, nextId, type);
     let uniqueKey = signature.toString();
 
     // check if it exists, and return it
@@ -986,12 +994,24 @@ export class Signature {
     /** Number of required parameters excluding `this`. Other parameters are considered optional. */
     public readonly requiredParameters: i32,
     /** Whether the last parameter is a rest parameter. */
-    public readonly hasRest: bool,
+    public readonly flags: SignatureFlags,
     /** Unique id representing this signature. */
     public readonly id: u32,
     /** Respective function type. */
     public readonly type: Type,
-  ) {}
+  ) {
+    if (this.hasEnv) assert(thisType != null);
+    assert(!(this.hasEnv && this.hasRest), "not implement first class function with rest parameters");
+  }
+
+  get hasRest(): bool {
+    return (this.flags & SignatureFlags.Rest) == SignatureFlags.Rest;
+  }
+
+  /** signature is first-class function */
+  get hasEnv(): bool {
+    return (this.flags & SignatureFlags.Env) == SignatureFlags.Env;
+  }
 
   get paramRefs(): TypeRef {
     let thisType = this.thisType;
@@ -1028,7 +1048,7 @@ export class Signature {
     }
 
     // check rest parameter
-    if (this.hasRest != other.hasRest) return false;
+    if (this.flags != other.flags) return false;
 
     // check return type
     if (!this.returnType.equals(other.returnType)) return false;
@@ -1049,16 +1069,19 @@ export class Signature {
 
   /** Tests if a value of this function type is assignable to a target of the specified function type. */
   isAssignableTo(target: Signature, checkCompatibleOverride: bool = false): bool {
-    let thisThisType = this.thisType;
-    let targetThisType = target.thisType;
-
-    if (thisThisType && targetThisType) {
-      const compatibleThisType = checkCompatibleOverride 
-        ? thisThisType.canExtendOrImplement(targetThisType)
-        : targetThisType.isAssignableTo(thisThisType);
-      if (!compatibleThisType) return false; 
-    } else if (thisThisType || targetThisType) {
-      return false;
+    if (!target.hasEnv) {
+      // first class function don't need to check this type
+      let thisThisType = this.thisType;
+      let targetThisType = target.thisType;
+  
+      if (thisThisType && targetThisType) {
+        const compatibleThisType = checkCompatibleOverride 
+          ? thisThisType.canExtendOrImplement(targetThisType)
+          : targetThisType.isAssignableTo(thisThisType);
+        if (!compatibleThisType) return false; 
+      } else if (thisThisType || targetThisType) {
+        return false;
+      }
     }
 
     // check rest parameter
@@ -1155,7 +1178,8 @@ export class Signature {
     let index = 0;
     let thisType = this.thisType;
     if (thisType) {
-      sb.push(validWat ? "this:" : "this: ");
+      sb.push(this.hasEnv ? "env" : "this");
+      sb.push(validWat ? ":" : ": ");
       sb.push(thisType.toString(validWat));
       index = 1;
     }
@@ -1177,7 +1201,7 @@ export class Signature {
   }
 
   /** Creates a clone of this signature that is safe to modify. */
-  clone(requiredParameters: i32 = this.requiredParameters, hasRest: bool = this.hasRest): Signature {
+  clone(requiredParameters: i32 = this.requiredParameters): Signature {
     let parameterTypes = this.parameterTypes;
     let numParameterTypes = parameterTypes.length;
     let cloneParameterTypes = new Array<Type>(numParameterTypes);
@@ -1190,7 +1214,7 @@ export class Signature {
       this.returnType,
       this.thisType,
       requiredParameters,
-      hasRest
+      this.flags
     );
   }
 }
diff --git a/std/assembly/builtins.ts b/std/assembly/builtins.ts
index 0f910a39e4..b0636f1695 100644
--- a/std/assembly/builtins.ts
+++ b/std/assembly/builtins.ts
@@ -202,6 +202,10 @@ export declare function assert<T>(isTrueish: T, message?: string): T;
 @unsafe @builtin
 export declare function unchecked<T>(expr: T): T;
 
+// @ts-ignore: decorator
+@unsafe @builtin
+export declare function experimental_first_class_function<T>(expr: T): T;
+
 // @ts-ignore: decorator
 @unsafe @builtin
 export declare function call_indirect<T>(index: u32, ...args: auto[]): T;
diff --git a/std/assembly/function.ts b/std/assembly/function.ts
index dd32696330..cf6d810016 100644
--- a/std/assembly/function.ts
+++ b/std/assembly/function.ts
@@ -4,6 +4,11 @@ type auto = i32;
   private _index: u32;
   private _env: usize;
 
+  constructor(index: u32, env: usize) {
+    this._index = index;
+    this._env = env;
+  }
+
   // @ts-ignore: this on getter
   get index(this: T): u32 {
     return load<u32>(changetype<usize>(this), offsetof<Function<T>>("_index"));
@@ -36,3 +41,18 @@ type auto = i32;
     __visit(this._env, cookie);
   }
 }
+
+export class FirstClassFunctionBase { // FIXME: should be Function later
+  private _index: u32;
+  private _env: usize;
+
+  constructor(index: u32, env: usize) {
+    this._index = index;
+    this._env = env;
+  }
+
+  @unsafe private __visit(cookie: u32): void {
+    // Env is either `null` (nop) or compiler-generated
+    __visit(this._env, cookie);
+  }
+}
diff --git a/std/assembly/index.d.ts b/std/assembly/index.d.ts
index 4dbee416a8..e596d2e83e 100644
--- a/std/assembly/index.d.ts
+++ b/std/assembly/index.d.ts
@@ -281,6 +281,11 @@ declare function decodeURI(str: string): string;
 /** Decodes a Uniform Resource Identifier (URI) component previously created by encodeURIComponent. */
 declare function decodeURIComponent(str: string): string;
 
+/** Experimental closure support, mark function expression as closure function */
+declare function experimental_first_class_function<T extends Function>(fn: T): experimental_first_class_function<T>;
+/** Experimental closure support, mark function type as closure function */
+declare type experimental_first_class_function<T extends Function> = T;
+
 /** Atomic operations. */
 declare namespace atomic {
   /** Atomically loads an integer value from memory and returns it. */
@@ -2308,6 +2313,11 @@ interface Function {
   toString(): string;
 }
 
+interface FirstClassFunctionBase {
+  readonly _index: u32;
+  _env: usize;
+}
+
 /**
  * Extracts the type of the 'this' parameter of a function type, or 'unknown' if the function type has no 'this' parameter.
  */
diff --git a/tests/compiler/builtins.debug.wat b/tests/compiler/builtins.debug.wat
index c5c210aea4..c430f6e6ad 100644
--- a/tests/compiler/builtins.debug.wat
+++ b/tests/compiler/builtins.debug.wat
@@ -3263,11 +3263,11 @@
   local.set $48
   i32.const 0
   local.set $49
-  i32.const 51
-  local.set $50
   i32.const 52
+  local.set $50
+  i32.const 53
   local.set $51
-  i32.const 52
+  i32.const 53
   local.set $52
   i32.const 256
   local.set $53
@@ -3312,7 +3312,7 @@
    unreachable
   end
   local.get $50
-  i32.const 51
+  i32.const 52
   i32.eq
   i32.eqz
   if
diff --git a/tests/compiler/builtins.release.wat b/tests/compiler/builtins.release.wat
index 28d046b18c..df9d7c1e6f 100644
--- a/tests/compiler/builtins.release.wat
+++ b/tests/compiler/builtins.release.wat
@@ -781,9 +781,9 @@
   i32.const 5
   f64.const 0
   f64.const 0
-  f64.const 51
-  f64.const 52
   f64.const 52
+  f64.const 53
+  f64.const 53
   call $~lib/builtins/trace
   global.get $~lib/memory/__stack_pointer
   local.tee $0
diff --git a/tests/compiler/first-class-function.debug.wat b/tests/compiler/first-class-function.debug.wat
new file mode 100644
index 0000000000..8c02d6d34e
--- /dev/null
+++ b/tests/compiler/first-class-function.debug.wat
@@ -0,0 +1,2761 @@
+(module
+ (type $0 (func (param i32 i32)))
+ (type $1 (func (param i32) (result i32)))
+ (type $2 (func (param i32)))
+ (type $3 (func))
+ (type $4 (func (result i32)))
+ (type $5 (func (param i32 i32) (result i32)))
+ (type $6 (func (param i32 i32 i32)))
+ (type $7 (func (param i32 i32 i32 i32)))
+ (type $8 (func (param i32 i32 i64) (result i32)))
+ (type $9 (func (param i32 i32 i32) (result i32)))
+ (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
+ (global $~lib/rt/itcms/total (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/threshold (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/state (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/visitCount (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/pinSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/iter (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/toSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/white (mut i32) (i32.const 0))
+ (global $~lib/shared/runtime/Runtime.Stub i32 (i32.const 0))
+ (global $~lib/shared/runtime/Runtime.Minimal i32 (i32.const 1))
+ (global $~lib/shared/runtime/Runtime.Incremental i32 (i32.const 2))
+ (global $~lib/rt/itcms/fromSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/tlsf/ROOT (mut i32) (i32.const 0))
+ (global $~lib/native/ASC_LOW_MEMORY_LIMIT i32 (i32.const 0))
+ (global $~argumentsLength (mut i32) (i32.const 0))
+ (global $first-class-function/foo (mut i32) (i32.const 512))
+ (global $first-class-function/fn1 (mut i32) (i32.const 0))
+ (global $first-class-function/fn2 (mut i32) (i32.const 0))
+ (global $~lib/rt/__rtti_base i32 (i32.const 528))
+ (global $~lib/memory/__data_end i32 (i32.const 560))
+ (global $~lib/memory/__stack_pointer (mut i32) (i32.const 33328))
+ (global $~lib/memory/__heap_base i32 (i32.const 33328))
+ (memory $0 1)
+ (data $0 (i32.const 12) "L\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00.\00\00\00f\00i\00r\00s\00t\00-\00c\00l\00a\00s\00s\00-\00f\00u\00n\00c\00t\00i\00o\00n\00.\00t\00s\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $1 (i32.const 92) "<\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00(\00\00\00A\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e\00\00\00\00\00")
+ (data $2 (i32.const 156) "<\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00 \00\00\00~\00l\00i\00b\00/\00r\00t\00/\00i\00t\00c\00m\00s\00.\00t\00s\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $3 (i32.const 224) "\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $4 (i32.const 256) "\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $5 (i32.const 284) "<\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e\00\00\00\00\00\00\00\00\00")
+ (data $6 (i32.const 348) ",\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00\14\00\00\00~\00l\00i\00b\00/\00r\00t\00.\00t\00s\00\00\00\00\00\00\00\00\00")
+ (data $7 (i32.const 400) "\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $8 (i32.const 428) "<\00\00\00\00\00\00\00\00\00\00\00\02\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00t\00l\00s\00f\00.\00t\00s\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (data $9 (i32.const 492) "\1c\00\00\00\00\00\00\00\00\00\00\00\06\00\00\00\08\00\00\00\03\00\00\00\00\00\00\00\00\00\00\00")
+ (data $10 (i32.const 528) "\07\00\00\00 \00\00\00 \00\00\00 \00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+ (table $0 4 4 funcref)
+ (elem $0 (i32.const 1) $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|0 $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|1 $start:first-class-function~anonymous|0)
+ (export "memory" (memory $0))
+ (start $~start)
+ (func $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|0 (param $this i32) (param $v i32)
+  local.get $v
+  i32.const 1234
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 3
+   i32.const 5
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $~lib/function/FirstClassFunctionBase#set:_index (param $this i32) (param $_index i32)
+  local.get $this
+  local.get $_index
+  i32.store
+ )
+ (func $~lib/function/FirstClassFunctionBase#set:_env (param $this i32) (param $_env i32)
+  local.get $this
+  local.get $_env
+  i32.store offset=4
+ )
+ (func $~lib/rt/itcms/Object#set:nextWithColor (param $this i32) (param $nextWithColor i32)
+  local.get $this
+  local.get $nextWithColor
+  i32.store offset=4
+ )
+ (func $~lib/rt/itcms/Object#set:prev (param $this i32) (param $prev i32)
+  local.get $this
+  local.get $prev
+  i32.store offset=8
+ )
+ (func $~lib/rt/itcms/initLazy (param $space i32) (result i32)
+  local.get $space
+  local.get $space
+  call $~lib/rt/itcms/Object#set:nextWithColor
+  local.get $space
+  local.get $space
+  call $~lib/rt/itcms/Object#set:prev
+  local.get $space
+  return
+ )
+ (func $~lib/rt/itcms/Object#get:nextWithColor (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=4
+ )
+ (func $~lib/rt/itcms/Object#get:next (param $this i32) (result i32)
+  local.get $this
+  call $~lib/rt/itcms/Object#get:nextWithColor
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  return
+ )
+ (func $~lib/rt/itcms/Object#get:color (param $this i32) (result i32)
+  local.get $this
+  call $~lib/rt/itcms/Object#get:nextWithColor
+  i32.const 3
+  i32.and
+  return
+ )
+ (func $~lib/rt/itcms/visitRoots (param $cookie i32)
+  (local $pn i32)
+  (local $iter i32)
+  local.get $cookie
+  call $~lib/rt/__visit_globals
+  global.get $~lib/rt/itcms/pinSpace
+  local.set $pn
+  local.get $pn
+  call $~lib/rt/itcms/Object#get:next
+  local.set $iter
+  loop $while-continue|0
+   local.get $iter
+   local.get $pn
+   i32.ne
+   if
+    i32.const 1
+    drop
+    local.get $iter
+    call $~lib/rt/itcms/Object#get:color
+    i32.const 3
+    i32.eq
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 176
+     i32.const 160
+     i32.const 16
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $iter
+    i32.const 20
+    i32.add
+    local.get $cookie
+    call $~lib/rt/__visit_members
+    local.get $iter
+    call $~lib/rt/itcms/Object#get:next
+    local.set $iter
+    br $while-continue|0
+   end
+  end
+ )
+ (func $~lib/rt/itcms/Object#set:color (param $this i32) (param $color i32)
+  local.get $this
+  local.get $this
+  call $~lib/rt/itcms/Object#get:nextWithColor
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.get $color
+  i32.or
+  call $~lib/rt/itcms/Object#set:nextWithColor
+ )
+ (func $~lib/rt/itcms/Object#get:prev (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=8
+ )
+ (func $~lib/rt/itcms/Object#set:next (param $this i32) (param $obj i32)
+  local.get $this
+  local.get $obj
+  local.get $this
+  call $~lib/rt/itcms/Object#get:nextWithColor
+  i32.const 3
+  i32.and
+  i32.or
+  call $~lib/rt/itcms/Object#set:nextWithColor
+ )
+ (func $~lib/rt/itcms/Object#unlink (param $this i32)
+  (local $next i32)
+  (local $prev i32)
+  local.get $this
+  call $~lib/rt/itcms/Object#get:next
+  local.set $next
+  local.get $next
+  i32.const 0
+  i32.eq
+  if
+   i32.const 1
+   drop
+   local.get $this
+   call $~lib/rt/itcms/Object#get:prev
+   i32.const 0
+   i32.eq
+   if (result i32)
+    local.get $this
+    global.get $~lib/memory/__heap_base
+    i32.lt_u
+   else
+    i32.const 0
+   end
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 176
+    i32.const 128
+    i32.const 18
+    call $~lib/builtins/abort
+    unreachable
+   end
+   return
+  end
+  local.get $this
+  call $~lib/rt/itcms/Object#get:prev
+  local.set $prev
+  i32.const 1
+  drop
+  local.get $prev
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 176
+   i32.const 132
+   i32.const 16
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $next
+  local.get $prev
+  call $~lib/rt/itcms/Object#set:prev
+  local.get $prev
+  local.get $next
+  call $~lib/rt/itcms/Object#set:next
+ )
+ (func $~lib/rt/itcms/Object#get:rtId (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=12
+ )
+ (func $~lib/shared/typeinfo/Typeinfo#get:flags (param $this i32) (result i32)
+  local.get $this
+  i32.load
+ )
+ (func $~lib/rt/__typeinfo (param $id i32) (result i32)
+  (local $ptr i32)
+  global.get $~lib/rt/__rtti_base
+  local.set $ptr
+  local.get $id
+  local.get $ptr
+  i32.load
+  i32.gt_u
+  if
+   i32.const 304
+   i32.const 368
+   i32.const 21
+   i32.const 28
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $ptr
+  i32.const 4
+  i32.add
+  local.get $id
+  i32.const 4
+  i32.mul
+  i32.add
+  call $~lib/shared/typeinfo/Typeinfo#get:flags
+  return
+ )
+ (func $~lib/rt/itcms/Object#get:isPointerfree (param $this i32) (result i32)
+  (local $rtId i32)
+  local.get $this
+  call $~lib/rt/itcms/Object#get:rtId
+  local.set $rtId
+  local.get $rtId
+  i32.const 2
+  i32.le_u
+  if (result i32)
+   i32.const 1
+  else
+   local.get $rtId
+   call $~lib/rt/__typeinfo
+   i32.const 32
+   i32.and
+   i32.const 0
+   i32.ne
+  end
+  return
+ )
+ (func $~lib/rt/itcms/Object#linkTo (param $this i32) (param $list i32) (param $withColor i32)
+  (local $prev i32)
+  local.get $list
+  call $~lib/rt/itcms/Object#get:prev
+  local.set $prev
+  local.get $this
+  local.get $list
+  local.get $withColor
+  i32.or
+  call $~lib/rt/itcms/Object#set:nextWithColor
+  local.get $this
+  local.get $prev
+  call $~lib/rt/itcms/Object#set:prev
+  local.get $prev
+  local.get $this
+  call $~lib/rt/itcms/Object#set:next
+  local.get $list
+  local.get $this
+  call $~lib/rt/itcms/Object#set:prev
+ )
+ (func $~lib/rt/itcms/Object#makeGray (param $this i32)
+  (local $1 i32)
+  local.get $this
+  global.get $~lib/rt/itcms/iter
+  i32.eq
+  if
+   local.get $this
+   call $~lib/rt/itcms/Object#get:prev
+   local.tee $1
+   i32.eqz
+   if (result i32)
+    i32.const 0
+    i32.const 176
+    i32.const 148
+    i32.const 30
+    call $~lib/builtins/abort
+    unreachable
+   else
+    local.get $1
+   end
+   global.set $~lib/rt/itcms/iter
+  end
+  local.get $this
+  call $~lib/rt/itcms/Object#unlink
+  local.get $this
+  global.get $~lib/rt/itcms/toSpace
+  local.get $this
+  call $~lib/rt/itcms/Object#get:isPointerfree
+  if (result i32)
+   global.get $~lib/rt/itcms/white
+   i32.eqz
+  else
+   i32.const 2
+  end
+  call $~lib/rt/itcms/Object#linkTo
+ )
+ (func $~lib/rt/itcms/__visit (param $ptr i32) (param $cookie i32)
+  (local $obj i32)
+  local.get $ptr
+  i32.eqz
+  if
+   return
+  end
+  local.get $ptr
+  i32.const 20
+  i32.sub
+  local.set $obj
+  i32.const 0
+  drop
+  local.get $obj
+  call $~lib/rt/itcms/Object#get:color
+  global.get $~lib/rt/itcms/white
+  i32.eq
+  if
+   local.get $obj
+   call $~lib/rt/itcms/Object#makeGray
+   global.get $~lib/rt/itcms/visitCount
+   i32.const 1
+   i32.add
+   global.set $~lib/rt/itcms/visitCount
+  end
+ )
+ (func $~lib/rt/itcms/visitStack (param $cookie i32)
+  (local $ptr i32)
+  global.get $~lib/memory/__stack_pointer
+  local.set $ptr
+  loop $while-continue|0
+   local.get $ptr
+   global.get $~lib/memory/__heap_base
+   i32.lt_u
+   if
+    local.get $ptr
+    i32.load
+    local.get $cookie
+    call $~lib/rt/itcms/__visit
+    local.get $ptr
+    i32.const 4
+    i32.add
+    local.set $ptr
+    br $while-continue|0
+   end
+  end
+ )
+ (func $~lib/rt/common/BLOCK#get:mmInfo (param $this i32) (result i32)
+  local.get $this
+  i32.load
+ )
+ (func $~lib/rt/itcms/Object#get:size (param $this i32) (result i32)
+  i32.const 4
+  local.get $this
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.add
+  return
+ )
+ (func $~lib/rt/tlsf/Root#set:flMap (param $this i32) (param $flMap i32)
+  local.get $this
+  local.get $flMap
+  i32.store
+ )
+ (func $~lib/rt/common/BLOCK#set:mmInfo (param $this i32) (param $mmInfo i32)
+  local.get $this
+  local.get $mmInfo
+  i32.store
+ )
+ (func $~lib/rt/tlsf/Block#set:prev (param $this i32) (param $prev i32)
+  local.get $this
+  local.get $prev
+  i32.store offset=4
+ )
+ (func $~lib/rt/tlsf/Block#set:next (param $this i32) (param $next i32)
+  local.get $this
+  local.get $next
+  i32.store offset=8
+ )
+ (func $~lib/rt/tlsf/Block#get:prev (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=4
+ )
+ (func $~lib/rt/tlsf/Block#get:next (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=8
+ )
+ (func $~lib/rt/tlsf/Root#get:flMap (param $this i32) (result i32)
+  local.get $this
+  i32.load
+ )
+ (func $~lib/rt/tlsf/removeBlock (param $root i32) (param $block i32)
+  (local $blockInfo i32)
+  (local $size i32)
+  (local $fl i32)
+  (local $sl i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $boundedSize i32)
+  (local $prev i32)
+  (local $next i32)
+  (local $root|11 i32)
+  (local $fl|12 i32)
+  (local $sl|13 i32)
+  (local $root|14 i32)
+  (local $fl|15 i32)
+  (local $sl|16 i32)
+  (local $head i32)
+  (local $root|18 i32)
+  (local $fl|19 i32)
+  (local $slMap i32)
+  (local $root|21 i32)
+  (local $fl|22 i32)
+  (local $slMap|23 i32)
+  local.get $block
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  local.set $blockInfo
+  i32.const 1
+  drop
+  local.get $blockInfo
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 268
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $blockInfo
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $size
+  i32.const 1
+  drop
+  local.get $size
+  i32.const 12
+  i32.ge_u
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 270
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $size
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $fl
+   local.get $size
+   i32.const 4
+   i32.shr_u
+   local.set $sl
+  else
+   local.get $size
+   local.tee $6
+   i32.const 1073741820
+   local.tee $7
+   local.get $6
+   local.get $7
+   i32.lt_u
+   select
+   local.set $boundedSize
+   i32.const 31
+   local.get $boundedSize
+   i32.clz
+   i32.sub
+   local.set $fl
+   local.get $boundedSize
+   local.get $fl
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $sl
+   local.get $fl
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $fl
+  end
+  i32.const 1
+  drop
+  local.get $fl
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $sl
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 284
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $block
+  call $~lib/rt/tlsf/Block#get:prev
+  local.set $prev
+  local.get $block
+  call $~lib/rt/tlsf/Block#get:next
+  local.set $next
+  local.get $prev
+  if
+   local.get $prev
+   local.get $next
+   call $~lib/rt/tlsf/Block#set:next
+  end
+  local.get $next
+  if
+   local.get $next
+   local.get $prev
+   call $~lib/rt/tlsf/Block#set:prev
+  end
+  local.get $block
+  block $~lib/rt/tlsf/GETHEAD|inlined.0 (result i32)
+   local.get $root
+   local.set $root|11
+   local.get $fl
+   local.set $fl|12
+   local.get $sl
+   local.set $sl|13
+   local.get $root|11
+   local.get $fl|12
+   i32.const 4
+   i32.shl
+   local.get $sl|13
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=96
+   br $~lib/rt/tlsf/GETHEAD|inlined.0
+  end
+  i32.eq
+  if
+   local.get $root
+   local.set $root|14
+   local.get $fl
+   local.set $fl|15
+   local.get $sl
+   local.set $sl|16
+   local.get $next
+   local.set $head
+   local.get $root|14
+   local.get $fl|15
+   i32.const 4
+   i32.shl
+   local.get $sl|16
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   local.get $head
+   i32.store offset=96
+   local.get $next
+   i32.eqz
+   if
+    block $~lib/rt/tlsf/GETSL|inlined.0 (result i32)
+     local.get $root
+     local.set $root|18
+     local.get $fl
+     local.set $fl|19
+     local.get $root|18
+     local.get $fl|19
+     i32.const 2
+     i32.shl
+     i32.add
+     i32.load offset=4
+     br $~lib/rt/tlsf/GETSL|inlined.0
+    end
+    local.set $slMap
+    local.get $root
+    local.set $root|21
+    local.get $fl
+    local.set $fl|22
+    local.get $slMap
+    i32.const 1
+    local.get $sl
+    i32.shl
+    i32.const -1
+    i32.xor
+    i32.and
+    local.tee $slMap
+    local.set $slMap|23
+    local.get $root|21
+    local.get $fl|22
+    i32.const 2
+    i32.shl
+    i32.add
+    local.get $slMap|23
+    i32.store offset=4
+    local.get $slMap
+    i32.eqz
+    if
+     local.get $root
+     local.get $root
+     call $~lib/rt/tlsf/Root#get:flMap
+     i32.const 1
+     local.get $fl
+     i32.shl
+     i32.const -1
+     i32.xor
+     i32.and
+     call $~lib/rt/tlsf/Root#set:flMap
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/insertBlock (param $root i32) (param $block i32)
+  (local $blockInfo i32)
+  (local $block|3 i32)
+  (local $right i32)
+  (local $rightInfo i32)
+  (local $block|6 i32)
+  (local $block|7 i32)
+  (local $left i32)
+  (local $leftInfo i32)
+  (local $size i32)
+  (local $fl i32)
+  (local $sl i32)
+  (local $13 i32)
+  (local $14 i32)
+  (local $boundedSize i32)
+  (local $root|16 i32)
+  (local $fl|17 i32)
+  (local $sl|18 i32)
+  (local $head i32)
+  (local $root|20 i32)
+  (local $fl|21 i32)
+  (local $sl|22 i32)
+  (local $head|23 i32)
+  (local $root|24 i32)
+  (local $fl|25 i32)
+  (local $root|26 i32)
+  (local $fl|27 i32)
+  (local $slMap i32)
+  i32.const 1
+  drop
+  local.get $block
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 201
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $block
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  local.set $blockInfo
+  i32.const 1
+  drop
+  local.get $blockInfo
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 203
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  block $~lib/rt/tlsf/GETRIGHT|inlined.0 (result i32)
+   local.get $block
+   local.set $block|3
+   local.get $block|3
+   i32.const 4
+   i32.add
+   local.get $block|3
+   call $~lib/rt/common/BLOCK#get:mmInfo
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   br $~lib/rt/tlsf/GETRIGHT|inlined.0
+  end
+  local.set $right
+  local.get $right
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  local.set $rightInfo
+  local.get $rightInfo
+  i32.const 1
+  i32.and
+  if
+   local.get $root
+   local.get $right
+   call $~lib/rt/tlsf/removeBlock
+   local.get $block
+   local.get $blockInfo
+   i32.const 4
+   i32.add
+   local.get $rightInfo
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   local.tee $blockInfo
+   call $~lib/rt/common/BLOCK#set:mmInfo
+   block $~lib/rt/tlsf/GETRIGHT|inlined.1 (result i32)
+    local.get $block
+    local.set $block|6
+    local.get $block|6
+    i32.const 4
+    i32.add
+    local.get $block|6
+    call $~lib/rt/common/BLOCK#get:mmInfo
+    i32.const 3
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.add
+    br $~lib/rt/tlsf/GETRIGHT|inlined.1
+   end
+   local.set $right
+   local.get $right
+   call $~lib/rt/common/BLOCK#get:mmInfo
+   local.set $rightInfo
+  end
+  local.get $blockInfo
+  i32.const 2
+  i32.and
+  if
+   block $~lib/rt/tlsf/GETFREELEFT|inlined.0 (result i32)
+    local.get $block
+    local.set $block|7
+    local.get $block|7
+    i32.const 4
+    i32.sub
+    i32.load
+    br $~lib/rt/tlsf/GETFREELEFT|inlined.0
+   end
+   local.set $left
+   local.get $left
+   call $~lib/rt/common/BLOCK#get:mmInfo
+   local.set $leftInfo
+   i32.const 1
+   drop
+   local.get $leftInfo
+   i32.const 1
+   i32.and
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 448
+    i32.const 221
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $root
+   local.get $left
+   call $~lib/rt/tlsf/removeBlock
+   local.get $left
+   local.set $block
+   local.get $block
+   local.get $leftInfo
+   i32.const 4
+   i32.add
+   local.get $blockInfo
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   local.tee $blockInfo
+   call $~lib/rt/common/BLOCK#set:mmInfo
+  end
+  local.get $right
+  local.get $rightInfo
+  i32.const 2
+  i32.or
+  call $~lib/rt/common/BLOCK#set:mmInfo
+  local.get $blockInfo
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $size
+  i32.const 1
+  drop
+  local.get $size
+  i32.const 12
+  i32.ge_u
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 233
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  drop
+  local.get $block
+  i32.const 4
+  i32.add
+  local.get $size
+  i32.add
+  local.get $right
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 234
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $right
+  i32.const 4
+  i32.sub
+  local.get $block
+  i32.store
+  local.get $size
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $fl
+   local.get $size
+   i32.const 4
+   i32.shr_u
+   local.set $sl
+  else
+   local.get $size
+   local.tee $13
+   i32.const 1073741820
+   local.tee $14
+   local.get $13
+   local.get $14
+   i32.lt_u
+   select
+   local.set $boundedSize
+   i32.const 31
+   local.get $boundedSize
+   i32.clz
+   i32.sub
+   local.set $fl
+   local.get $boundedSize
+   local.get $fl
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $sl
+   local.get $fl
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $fl
+  end
+  i32.const 1
+  drop
+  local.get $fl
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $sl
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 251
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  block $~lib/rt/tlsf/GETHEAD|inlined.1 (result i32)
+   local.get $root
+   local.set $root|16
+   local.get $fl
+   local.set $fl|17
+   local.get $sl
+   local.set $sl|18
+   local.get $root|16
+   local.get $fl|17
+   i32.const 4
+   i32.shl
+   local.get $sl|18
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=96
+   br $~lib/rt/tlsf/GETHEAD|inlined.1
+  end
+  local.set $head
+  local.get $block
+  i32.const 0
+  call $~lib/rt/tlsf/Block#set:prev
+  local.get $block
+  local.get $head
+  call $~lib/rt/tlsf/Block#set:next
+  local.get $head
+  if
+   local.get $head
+   local.get $block
+   call $~lib/rt/tlsf/Block#set:prev
+  end
+  local.get $root
+  local.set $root|20
+  local.get $fl
+  local.set $fl|21
+  local.get $sl
+  local.set $sl|22
+  local.get $block
+  local.set $head|23
+  local.get $root|20
+  local.get $fl|21
+  i32.const 4
+  i32.shl
+  local.get $sl|22
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $head|23
+  i32.store offset=96
+  local.get $root
+  local.get $root
+  call $~lib/rt/tlsf/Root#get:flMap
+  i32.const 1
+  local.get $fl
+  i32.shl
+  i32.or
+  call $~lib/rt/tlsf/Root#set:flMap
+  local.get $root
+  local.set $root|26
+  local.get $fl
+  local.set $fl|27
+  block $~lib/rt/tlsf/GETSL|inlined.1 (result i32)
+   local.get $root
+   local.set $root|24
+   local.get $fl
+   local.set $fl|25
+   local.get $root|24
+   local.get $fl|25
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=4
+   br $~lib/rt/tlsf/GETSL|inlined.1
+  end
+  i32.const 1
+  local.get $sl
+  i32.shl
+  i32.or
+  local.set $slMap
+  local.get $root|26
+  local.get $fl|27
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $slMap
+  i32.store offset=4
+ )
+ (func $~lib/rt/tlsf/addMemory (param $root i32) (param $start i32) (param $endU64 i64) (result i32)
+  (local $end i32)
+  (local $root|4 i32)
+  (local $tail i32)
+  (local $tailInfo i32)
+  (local $size i32)
+  (local $leftSize i32)
+  (local $left i32)
+  (local $root|10 i32)
+  (local $tail|11 i32)
+  local.get $endU64
+  i32.wrap_i64
+  local.set $end
+  i32.const 1
+  drop
+  local.get $start
+  i64.extend_i32_u
+  local.get $endU64
+  i64.le_u
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 382
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $start
+  i32.const 4
+  i32.add
+  i32.const 15
+  i32.add
+  i32.const 15
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.const 4
+  i32.sub
+  local.set $start
+  local.get $end
+  i32.const 15
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $end
+  block $~lib/rt/tlsf/GETTAIL|inlined.0 (result i32)
+   local.get $root
+   local.set $root|4
+   local.get $root|4
+   i32.load offset=1568
+   br $~lib/rt/tlsf/GETTAIL|inlined.0
+  end
+  local.set $tail
+  i32.const 0
+  local.set $tailInfo
+  local.get $tail
+  if
+   i32.const 1
+   drop
+   local.get $start
+   local.get $tail
+   i32.const 4
+   i32.add
+   i32.ge_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 448
+    i32.const 389
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $start
+   i32.const 16
+   i32.sub
+   local.get $tail
+   i32.eq
+   if
+    local.get $start
+    i32.const 16
+    i32.sub
+    local.set $start
+    local.get $tail
+    call $~lib/rt/common/BLOCK#get:mmInfo
+    local.set $tailInfo
+   else
+   end
+  else
+   i32.const 1
+   drop
+   local.get $start
+   local.get $root
+   i32.const 1572
+   i32.add
+   i32.ge_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 448
+    i32.const 402
+    i32.const 5
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  local.get $end
+  local.get $start
+  i32.sub
+  local.set $size
+  local.get $size
+  i32.const 4
+  i32.const 12
+  i32.add
+  i32.const 4
+  i32.add
+  i32.lt_u
+  if
+   i32.const 0
+   return
+  end
+  local.get $size
+  i32.const 2
+  i32.const 4
+  i32.mul
+  i32.sub
+  local.set $leftSize
+  local.get $start
+  local.set $left
+  local.get $left
+  local.get $leftSize
+  i32.const 1
+  i32.or
+  local.get $tailInfo
+  i32.const 2
+  i32.and
+  i32.or
+  call $~lib/rt/common/BLOCK#set:mmInfo
+  local.get $left
+  i32.const 0
+  call $~lib/rt/tlsf/Block#set:prev
+  local.get $left
+  i32.const 0
+  call $~lib/rt/tlsf/Block#set:next
+  local.get $start
+  i32.const 4
+  i32.add
+  local.get $leftSize
+  i32.add
+  local.set $tail
+  local.get $tail
+  i32.const 0
+  i32.const 2
+  i32.or
+  call $~lib/rt/common/BLOCK#set:mmInfo
+  local.get $root
+  local.set $root|10
+  local.get $tail
+  local.set $tail|11
+  local.get $root|10
+  local.get $tail|11
+  i32.store offset=1568
+  local.get $root
+  local.get $left
+  call $~lib/rt/tlsf/insertBlock
+  i32.const 1
+  return
+ )
+ (func $~lib/rt/tlsf/initialize
+  (local $rootOffset i32)
+  (local $pagesBefore i32)
+  (local $pagesNeeded i32)
+  (local $root i32)
+  (local $root|4 i32)
+  (local $tail i32)
+  (local $fl i32)
+  (local $root|7 i32)
+  (local $fl|8 i32)
+  (local $slMap i32)
+  (local $sl i32)
+  (local $root|11 i32)
+  (local $fl|12 i32)
+  (local $sl|13 i32)
+  (local $head i32)
+  (local $memStart i32)
+  i32.const 0
+  drop
+  global.get $~lib/memory/__heap_base
+  i32.const 15
+  i32.add
+  i32.const 15
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $rootOffset
+  memory.size
+  local.set $pagesBefore
+  local.get $rootOffset
+  i32.const 1572
+  i32.add
+  i32.const 65535
+  i32.add
+  i32.const 65535
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.const 16
+  i32.shr_u
+  local.set $pagesNeeded
+  local.get $pagesNeeded
+  local.get $pagesBefore
+  i32.gt_s
+  if (result i32)
+   local.get $pagesNeeded
+   local.get $pagesBefore
+   i32.sub
+   memory.grow
+   i32.const 0
+   i32.lt_s
+  else
+   i32.const 0
+  end
+  if
+   unreachable
+  end
+  local.get $rootOffset
+  local.set $root
+  local.get $root
+  i32.const 0
+  call $~lib/rt/tlsf/Root#set:flMap
+  local.get $root
+  local.set $root|4
+  i32.const 0
+  local.set $tail
+  local.get $root|4
+  local.get $tail
+  i32.store offset=1568
+  i32.const 0
+  local.set $fl
+  loop $for-loop|0
+   local.get $fl
+   i32.const 23
+   i32.lt_u
+   if
+    local.get $root
+    local.set $root|7
+    local.get $fl
+    local.set $fl|8
+    i32.const 0
+    local.set $slMap
+    local.get $root|7
+    local.get $fl|8
+    i32.const 2
+    i32.shl
+    i32.add
+    local.get $slMap
+    i32.store offset=4
+    i32.const 0
+    local.set $sl
+    loop $for-loop|1
+     local.get $sl
+     i32.const 16
+     i32.lt_u
+     if
+      local.get $root
+      local.set $root|11
+      local.get $fl
+      local.set $fl|12
+      local.get $sl
+      local.set $sl|13
+      i32.const 0
+      local.set $head
+      local.get $root|11
+      local.get $fl|12
+      i32.const 4
+      i32.shl
+      local.get $sl|13
+      i32.add
+      i32.const 2
+      i32.shl
+      i32.add
+      local.get $head
+      i32.store offset=96
+      local.get $sl
+      i32.const 1
+      i32.add
+      local.set $sl
+      br $for-loop|1
+     end
+    end
+    local.get $fl
+    i32.const 1
+    i32.add
+    local.set $fl
+    br $for-loop|0
+   end
+  end
+  local.get $rootOffset
+  i32.const 1572
+  i32.add
+  local.set $memStart
+  i32.const 0
+  drop
+  local.get $root
+  local.get $memStart
+  memory.size
+  i64.extend_i32_s
+  i64.const 16
+  i64.shl
+  call $~lib/rt/tlsf/addMemory
+  drop
+  local.get $root
+  global.set $~lib/rt/tlsf/ROOT
+ )
+ (func $~lib/rt/tlsf/checkUsedBlock (param $ptr i32) (result i32)
+  (local $block i32)
+  local.get $ptr
+  i32.const 4
+  i32.sub
+  local.set $block
+  local.get $ptr
+  i32.const 0
+  i32.ne
+  if (result i32)
+   local.get $ptr
+   i32.const 15
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  if (result i32)
+   local.get $block
+   call $~lib/rt/common/BLOCK#get:mmInfo
+   i32.const 1
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 562
+   i32.const 3
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $block
+  return
+ )
+ (func $~lib/rt/tlsf/freeBlock (param $root i32) (param $block i32)
+  i32.const 0
+  drop
+  local.get $block
+  local.get $block
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  i32.const 1
+  i32.or
+  call $~lib/rt/common/BLOCK#set:mmInfo
+  local.get $root
+  local.get $block
+  call $~lib/rt/tlsf/insertBlock
+ )
+ (func $~lib/rt/tlsf/__free (param $ptr i32)
+  local.get $ptr
+  global.get $~lib/memory/__heap_base
+  i32.lt_u
+  if
+   return
+  end
+  global.get $~lib/rt/tlsf/ROOT
+  i32.eqz
+  if
+   call $~lib/rt/tlsf/initialize
+  end
+  global.get $~lib/rt/tlsf/ROOT
+  local.get $ptr
+  call $~lib/rt/tlsf/checkUsedBlock
+  call $~lib/rt/tlsf/freeBlock
+ )
+ (func $~lib/rt/itcms/free (param $obj i32)
+  local.get $obj
+  global.get $~lib/memory/__heap_base
+  i32.lt_u
+  if
+   local.get $obj
+   i32.const 0
+   call $~lib/rt/itcms/Object#set:nextWithColor
+   local.get $obj
+   i32.const 0
+   call $~lib/rt/itcms/Object#set:prev
+  else
+   global.get $~lib/rt/itcms/total
+   local.get $obj
+   call $~lib/rt/itcms/Object#get:size
+   i32.sub
+   global.set $~lib/rt/itcms/total
+   i32.const 0
+   drop
+   local.get $obj
+   i32.const 4
+   i32.add
+   call $~lib/rt/tlsf/__free
+  end
+ )
+ (func $~lib/rt/itcms/step (result i32)
+  (local $obj i32)
+  (local $1 i32)
+  (local $black i32)
+  (local $from i32)
+  block $break|0
+   block $case2|0
+    block $case1|0
+     block $case0|0
+      global.get $~lib/rt/itcms/state
+      local.set $1
+      local.get $1
+      i32.const 0
+      i32.eq
+      br_if $case0|0
+      local.get $1
+      i32.const 1
+      i32.eq
+      br_if $case1|0
+      local.get $1
+      i32.const 2
+      i32.eq
+      br_if $case2|0
+      br $break|0
+     end
+     i32.const 1
+     global.set $~lib/rt/itcms/state
+     i32.const 0
+     global.set $~lib/rt/itcms/visitCount
+     i32.const 0
+     call $~lib/rt/itcms/visitRoots
+     global.get $~lib/rt/itcms/toSpace
+     global.set $~lib/rt/itcms/iter
+     global.get $~lib/rt/itcms/visitCount
+     i32.const 1
+     i32.mul
+     return
+    end
+    global.get $~lib/rt/itcms/white
+    i32.eqz
+    local.set $black
+    global.get $~lib/rt/itcms/iter
+    call $~lib/rt/itcms/Object#get:next
+    local.set $obj
+    loop $while-continue|1
+     local.get $obj
+     global.get $~lib/rt/itcms/toSpace
+     i32.ne
+     if
+      local.get $obj
+      global.set $~lib/rt/itcms/iter
+      local.get $obj
+      call $~lib/rt/itcms/Object#get:color
+      local.get $black
+      i32.ne
+      if
+       local.get $obj
+       local.get $black
+       call $~lib/rt/itcms/Object#set:color
+       i32.const 0
+       global.set $~lib/rt/itcms/visitCount
+       local.get $obj
+       i32.const 20
+       i32.add
+       i32.const 0
+       call $~lib/rt/__visit_members
+       global.get $~lib/rt/itcms/visitCount
+       i32.const 1
+       i32.mul
+       return
+      end
+      local.get $obj
+      call $~lib/rt/itcms/Object#get:next
+      local.set $obj
+      br $while-continue|1
+     end
+    end
+    i32.const 0
+    global.set $~lib/rt/itcms/visitCount
+    i32.const 0
+    call $~lib/rt/itcms/visitRoots
+    global.get $~lib/rt/itcms/iter
+    call $~lib/rt/itcms/Object#get:next
+    local.set $obj
+    local.get $obj
+    global.get $~lib/rt/itcms/toSpace
+    i32.eq
+    if
+     i32.const 0
+     call $~lib/rt/itcms/visitStack
+     global.get $~lib/rt/itcms/iter
+     call $~lib/rt/itcms/Object#get:next
+     local.set $obj
+     loop $while-continue|2
+      local.get $obj
+      global.get $~lib/rt/itcms/toSpace
+      i32.ne
+      if
+       local.get $obj
+       call $~lib/rt/itcms/Object#get:color
+       local.get $black
+       i32.ne
+       if
+        local.get $obj
+        local.get $black
+        call $~lib/rt/itcms/Object#set:color
+        local.get $obj
+        i32.const 20
+        i32.add
+        i32.const 0
+        call $~lib/rt/__visit_members
+       end
+       local.get $obj
+       call $~lib/rt/itcms/Object#get:next
+       local.set $obj
+       br $while-continue|2
+      end
+     end
+     global.get $~lib/rt/itcms/fromSpace
+     local.set $from
+     global.get $~lib/rt/itcms/toSpace
+     global.set $~lib/rt/itcms/fromSpace
+     local.get $from
+     global.set $~lib/rt/itcms/toSpace
+     local.get $black
+     global.set $~lib/rt/itcms/white
+     local.get $from
+     call $~lib/rt/itcms/Object#get:next
+     global.set $~lib/rt/itcms/iter
+     i32.const 2
+     global.set $~lib/rt/itcms/state
+    end
+    global.get $~lib/rt/itcms/visitCount
+    i32.const 1
+    i32.mul
+    return
+   end
+   global.get $~lib/rt/itcms/iter
+   local.set $obj
+   local.get $obj
+   global.get $~lib/rt/itcms/toSpace
+   i32.ne
+   if
+    local.get $obj
+    call $~lib/rt/itcms/Object#get:next
+    global.set $~lib/rt/itcms/iter
+    i32.const 1
+    drop
+    local.get $obj
+    call $~lib/rt/itcms/Object#get:color
+    global.get $~lib/rt/itcms/white
+    i32.eqz
+    i32.eq
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 176
+     i32.const 229
+     i32.const 20
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $obj
+    call $~lib/rt/itcms/free
+    i32.const 10
+    return
+   end
+   global.get $~lib/rt/itcms/toSpace
+   global.get $~lib/rt/itcms/toSpace
+   call $~lib/rt/itcms/Object#set:nextWithColor
+   global.get $~lib/rt/itcms/toSpace
+   global.get $~lib/rt/itcms/toSpace
+   call $~lib/rt/itcms/Object#set:prev
+   i32.const 0
+   global.set $~lib/rt/itcms/state
+   br $break|0
+  end
+  i32.const 0
+  return
+ )
+ (func $~lib/rt/itcms/interrupt
+  (local $budget i32)
+  i32.const 0
+  drop
+  i32.const 0
+  drop
+  i32.const 1024
+  i32.const 200
+  i32.mul
+  i32.const 100
+  i32.div_u
+  local.set $budget
+  loop $do-loop|0
+   local.get $budget
+   call $~lib/rt/itcms/step
+   i32.sub
+   local.set $budget
+   global.get $~lib/rt/itcms/state
+   i32.const 0
+   i32.eq
+   if
+    i32.const 0
+    drop
+    global.get $~lib/rt/itcms/total
+    i64.extend_i32_u
+    i32.const 200
+    i64.extend_i32_u
+    i64.mul
+    i64.const 100
+    i64.div_u
+    i32.wrap_i64
+    i32.const 1024
+    i32.add
+    global.set $~lib/rt/itcms/threshold
+    i32.const 0
+    drop
+    return
+   end
+   local.get $budget
+   i32.const 0
+   i32.gt_s
+   br_if $do-loop|0
+  end
+  i32.const 0
+  drop
+  global.get $~lib/rt/itcms/total
+  i32.const 1024
+  global.get $~lib/rt/itcms/total
+  global.get $~lib/rt/itcms/threshold
+  i32.sub
+  i32.const 1024
+  i32.lt_u
+  i32.mul
+  i32.add
+  global.set $~lib/rt/itcms/threshold
+  i32.const 0
+  drop
+ )
+ (func $~lib/rt/tlsf/computeSize (param $size i32) (result i32)
+  local.get $size
+  i32.const 12
+  i32.le_u
+  if (result i32)
+   i32.const 12
+  else
+   local.get $size
+   i32.const 4
+   i32.add
+   i32.const 15
+   i32.add
+   i32.const 15
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 4
+   i32.sub
+  end
+  return
+ )
+ (func $~lib/rt/tlsf/prepareSize (param $size i32) (result i32)
+  local.get $size
+  i32.const 1073741820
+  i32.gt_u
+  if
+   i32.const 112
+   i32.const 448
+   i32.const 461
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $size
+  call $~lib/rt/tlsf/computeSize
+  return
+ )
+ (func $~lib/rt/tlsf/roundSize (param $size i32) (result i32)
+  local.get $size
+  i32.const 536870910
+  i32.lt_u
+  if (result i32)
+   local.get $size
+   i32.const 1
+   i32.const 27
+   local.get $size
+   i32.clz
+   i32.sub
+   i32.shl
+   i32.add
+   i32.const 1
+   i32.sub
+  else
+   local.get $size
+  end
+  return
+ )
+ (func $~lib/rt/tlsf/searchBlock (param $root i32) (param $size i32) (result i32)
+  (local $fl i32)
+  (local $sl i32)
+  (local $requestSize i32)
+  (local $root|5 i32)
+  (local $fl|6 i32)
+  (local $slMap i32)
+  (local $head i32)
+  (local $flMap i32)
+  (local $root|10 i32)
+  (local $fl|11 i32)
+  (local $root|12 i32)
+  (local $fl|13 i32)
+  (local $sl|14 i32)
+  (local $root|15 i32)
+  (local $fl|16 i32)
+  (local $sl|17 i32)
+  local.get $size
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $fl
+   local.get $size
+   i32.const 4
+   i32.shr_u
+   local.set $sl
+  else
+   local.get $size
+   call $~lib/rt/tlsf/roundSize
+   local.set $requestSize
+   i32.const 4
+   i32.const 8
+   i32.mul
+   i32.const 1
+   i32.sub
+   local.get $requestSize
+   i32.clz
+   i32.sub
+   local.set $fl
+   local.get $requestSize
+   local.get $fl
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $sl
+   local.get $fl
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $fl
+  end
+  i32.const 1
+  drop
+  local.get $fl
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $sl
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 334
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  block $~lib/rt/tlsf/GETSL|inlined.2 (result i32)
+   local.get $root
+   local.set $root|5
+   local.get $fl
+   local.set $fl|6
+   local.get $root|5
+   local.get $fl|6
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=4
+   br $~lib/rt/tlsf/GETSL|inlined.2
+  end
+  i32.const 0
+  i32.const -1
+  i32.xor
+  local.get $sl
+  i32.shl
+  i32.and
+  local.set $slMap
+  i32.const 0
+  local.set $head
+  local.get $slMap
+  i32.eqz
+  if
+   local.get $root
+   call $~lib/rt/tlsf/Root#get:flMap
+   i32.const 0
+   i32.const -1
+   i32.xor
+   local.get $fl
+   i32.const 1
+   i32.add
+   i32.shl
+   i32.and
+   local.set $flMap
+   local.get $flMap
+   i32.eqz
+   if
+    i32.const 0
+    local.set $head
+   else
+    local.get $flMap
+    i32.ctz
+    local.set $fl
+    block $~lib/rt/tlsf/GETSL|inlined.3 (result i32)
+     local.get $root
+     local.set $root|10
+     local.get $fl
+     local.set $fl|11
+     local.get $root|10
+     local.get $fl|11
+     i32.const 2
+     i32.shl
+     i32.add
+     i32.load offset=4
+     br $~lib/rt/tlsf/GETSL|inlined.3
+    end
+    local.set $slMap
+    i32.const 1
+    drop
+    local.get $slMap
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 448
+     i32.const 347
+     i32.const 18
+     call $~lib/builtins/abort
+     unreachable
+    end
+    block $~lib/rt/tlsf/GETHEAD|inlined.2 (result i32)
+     local.get $root
+     local.set $root|12
+     local.get $fl
+     local.set $fl|13
+     local.get $slMap
+     i32.ctz
+     local.set $sl|14
+     local.get $root|12
+     local.get $fl|13
+     i32.const 4
+     i32.shl
+     local.get $sl|14
+     i32.add
+     i32.const 2
+     i32.shl
+     i32.add
+     i32.load offset=96
+     br $~lib/rt/tlsf/GETHEAD|inlined.2
+    end
+    local.set $head
+   end
+  else
+   block $~lib/rt/tlsf/GETHEAD|inlined.3 (result i32)
+    local.get $root
+    local.set $root|15
+    local.get $fl
+    local.set $fl|16
+    local.get $slMap
+    i32.ctz
+    local.set $sl|17
+    local.get $root|15
+    local.get $fl|16
+    i32.const 4
+    i32.shl
+    local.get $sl|17
+    i32.add
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=96
+    br $~lib/rt/tlsf/GETHEAD|inlined.3
+   end
+   local.set $head
+  end
+  local.get $head
+  return
+ )
+ (func $~lib/rt/tlsf/growMemory (param $root i32) (param $size i32)
+  (local $pagesBefore i32)
+  (local $root|3 i32)
+  (local $pagesNeeded i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $pagesWanted i32)
+  (local $pagesAfter i32)
+  i32.const 0
+  drop
+  local.get $size
+  i32.const 256
+  i32.ge_u
+  if
+   local.get $size
+   call $~lib/rt/tlsf/roundSize
+   local.set $size
+  end
+  memory.size
+  local.set $pagesBefore
+  local.get $size
+  i32.const 4
+  local.get $pagesBefore
+  i32.const 16
+  i32.shl
+  i32.const 4
+  i32.sub
+  block $~lib/rt/tlsf/GETTAIL|inlined.1 (result i32)
+   local.get $root
+   local.set $root|3
+   local.get $root|3
+   i32.load offset=1568
+   br $~lib/rt/tlsf/GETTAIL|inlined.1
+  end
+  i32.ne
+  i32.shl
+  i32.add
+  local.set $size
+  local.get $size
+  i32.const 65535
+  i32.add
+  i32.const 65535
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.const 16
+  i32.shr_u
+  local.set $pagesNeeded
+  local.get $pagesBefore
+  local.tee $5
+  local.get $pagesNeeded
+  local.tee $6
+  local.get $5
+  local.get $6
+  i32.gt_s
+  select
+  local.set $pagesWanted
+  local.get $pagesWanted
+  memory.grow
+  i32.const 0
+  i32.lt_s
+  if
+   local.get $pagesNeeded
+   memory.grow
+   i32.const 0
+   i32.lt_s
+   if
+    unreachable
+   end
+  end
+  memory.size
+  local.set $pagesAfter
+  local.get $root
+  local.get $pagesBefore
+  i32.const 16
+  i32.shl
+  local.get $pagesAfter
+  i64.extend_i32_s
+  i64.const 16
+  i64.shl
+  call $~lib/rt/tlsf/addMemory
+  drop
+ )
+ (func $~lib/rt/tlsf/prepareBlock (param $root i32) (param $block i32) (param $size i32)
+  (local $blockInfo i32)
+  (local $remaining i32)
+  (local $spare i32)
+  (local $block|6 i32)
+  (local $block|7 i32)
+  local.get $block
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  local.set $blockInfo
+  i32.const 1
+  drop
+  local.get $size
+  i32.const 4
+  i32.add
+  i32.const 15
+  i32.and
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 361
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $blockInfo
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.get $size
+  i32.sub
+  local.set $remaining
+  local.get $remaining
+  i32.const 4
+  i32.const 12
+  i32.add
+  i32.ge_u
+  if
+   local.get $block
+   local.get $size
+   local.get $blockInfo
+   i32.const 2
+   i32.and
+   i32.or
+   call $~lib/rt/common/BLOCK#set:mmInfo
+   local.get $block
+   i32.const 4
+   i32.add
+   local.get $size
+   i32.add
+   local.set $spare
+   local.get $spare
+   local.get $remaining
+   i32.const 4
+   i32.sub
+   i32.const 1
+   i32.or
+   call $~lib/rt/common/BLOCK#set:mmInfo
+   local.get $root
+   local.get $spare
+   call $~lib/rt/tlsf/insertBlock
+  else
+   local.get $block
+   local.get $blockInfo
+   i32.const 1
+   i32.const -1
+   i32.xor
+   i32.and
+   call $~lib/rt/common/BLOCK#set:mmInfo
+   block $~lib/rt/tlsf/GETRIGHT|inlined.3 (result i32)
+    local.get $block
+    local.set $block|7
+    local.get $block|7
+    i32.const 4
+    i32.add
+    local.get $block|7
+    call $~lib/rt/common/BLOCK#get:mmInfo
+    i32.const 3
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.add
+    br $~lib/rt/tlsf/GETRIGHT|inlined.3
+   end
+   block $~lib/rt/tlsf/GETRIGHT|inlined.2 (result i32)
+    local.get $block
+    local.set $block|6
+    local.get $block|6
+    i32.const 4
+    i32.add
+    local.get $block|6
+    call $~lib/rt/common/BLOCK#get:mmInfo
+    i32.const 3
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.add
+    br $~lib/rt/tlsf/GETRIGHT|inlined.2
+   end
+   call $~lib/rt/common/BLOCK#get:mmInfo
+   i32.const 2
+   i32.const -1
+   i32.xor
+   i32.and
+   call $~lib/rt/common/BLOCK#set:mmInfo
+  end
+ )
+ (func $~lib/rt/tlsf/allocateBlock (param $root i32) (param $size i32) (result i32)
+  (local $payloadSize i32)
+  (local $block i32)
+  local.get $size
+  call $~lib/rt/tlsf/prepareSize
+  local.set $payloadSize
+  local.get $root
+  local.get $payloadSize
+  call $~lib/rt/tlsf/searchBlock
+  local.set $block
+  local.get $block
+  i32.eqz
+  if
+   local.get $root
+   local.get $payloadSize
+   call $~lib/rt/tlsf/growMemory
+   local.get $root
+   local.get $payloadSize
+   call $~lib/rt/tlsf/searchBlock
+   local.set $block
+   i32.const 1
+   drop
+   local.get $block
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 448
+    i32.const 499
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  i32.const 1
+  drop
+  local.get $block
+  call $~lib/rt/common/BLOCK#get:mmInfo
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.get $payloadSize
+  i32.ge_u
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 448
+   i32.const 501
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $root
+  local.get $block
+  call $~lib/rt/tlsf/removeBlock
+  local.get $root
+  local.get $block
+  local.get $payloadSize
+  call $~lib/rt/tlsf/prepareBlock
+  i32.const 0
+  drop
+  local.get $block
+  return
+ )
+ (func $~lib/rt/tlsf/__alloc (param $size i32) (result i32)
+  global.get $~lib/rt/tlsf/ROOT
+  i32.eqz
+  if
+   call $~lib/rt/tlsf/initialize
+  end
+  global.get $~lib/rt/tlsf/ROOT
+  local.get $size
+  call $~lib/rt/tlsf/allocateBlock
+  i32.const 4
+  i32.add
+  return
+ )
+ (func $~lib/rt/itcms/Object#set:rtId (param $this i32) (param $rtId i32)
+  local.get $this
+  local.get $rtId
+  i32.store offset=12
+ )
+ (func $~lib/rt/itcms/Object#set:rtSize (param $this i32) (param $rtSize i32)
+  local.get $this
+  local.get $rtSize
+  i32.store offset=16
+ )
+ (func $~lib/rt/itcms/__new (param $size i32) (param $id i32) (result i32)
+  (local $obj i32)
+  (local $ptr i32)
+  local.get $size
+  i32.const 1073741804
+  i32.ge_u
+  if
+   i32.const 112
+   i32.const 176
+   i32.const 261
+   i32.const 31
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/rt/itcms/total
+  global.get $~lib/rt/itcms/threshold
+  i32.ge_u
+  if
+   call $~lib/rt/itcms/interrupt
+  end
+  i32.const 16
+  local.get $size
+  i32.add
+  call $~lib/rt/tlsf/__alloc
+  i32.const 4
+  i32.sub
+  local.set $obj
+  local.get $obj
+  local.get $id
+  call $~lib/rt/itcms/Object#set:rtId
+  local.get $obj
+  local.get $size
+  call $~lib/rt/itcms/Object#set:rtSize
+  local.get $obj
+  global.get $~lib/rt/itcms/fromSpace
+  global.get $~lib/rt/itcms/white
+  call $~lib/rt/itcms/Object#linkTo
+  global.get $~lib/rt/itcms/total
+  local.get $obj
+  call $~lib/rt/itcms/Object#get:size
+  i32.add
+  global.set $~lib/rt/itcms/total
+  local.get $obj
+  i32.const 20
+  i32.add
+  local.set $ptr
+  local.get $ptr
+  i32.const 0
+  local.get $size
+  memory.fill
+  local.get $ptr
+  return
+ )
+ (func $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|1 (param $this i32) (param $v i32)
+ )
+ (func $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:index (param $this i32) (result i32)
+  local.get $this
+  i32.load
+  return
+ )
+ (func $~lib/rt/itcms/__collect
+  i32.const 0
+  drop
+  global.get $~lib/rt/itcms/state
+  i32.const 0
+  i32.gt_s
+  if
+   loop $while-continue|0
+    global.get $~lib/rt/itcms/state
+    i32.const 0
+    i32.ne
+    if
+     call $~lib/rt/itcms/step
+     drop
+     br $while-continue|0
+    end
+   end
+  end
+  call $~lib/rt/itcms/step
+  drop
+  loop $while-continue|1
+   global.get $~lib/rt/itcms/state
+   i32.const 0
+   i32.ne
+   if
+    call $~lib/rt/itcms/step
+    drop
+    br $while-continue|1
+   end
+  end
+  global.get $~lib/rt/itcms/total
+  i64.extend_i32_u
+  i32.const 200
+  i64.extend_i32_u
+  i64.mul
+  i64.const 100
+  i64.div_u
+  i32.wrap_i64
+  i32.const 1024
+  i32.add
+  global.set $~lib/rt/itcms/threshold
+  i32.const 0
+  drop
+  i32.const 0
+  drop
+ )
+ (func $~lib/rt/__visit_globals (param $0 i32)
+  (local $1 i32)
+  global.get $first-class-function/fn1
+  local.tee $1
+  if
+   local.get $1
+   local.get $0
+   call $~lib/rt/itcms/__visit
+  end
+  global.get $first-class-function/fn2
+  local.tee $1
+  if
+   local.get $1
+   local.get $0
+   call $~lib/rt/itcms/__visit
+  end
+  i32.const 304
+  local.get $0
+  call $~lib/rt/itcms/__visit
+  i32.const 112
+  local.get $0
+  call $~lib/rt/itcms/__visit
+ )
+ (func $~lib/arraybuffer/ArrayBufferView~visit (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  local.get $0
+  local.get $1
+  call $~lib/object/Object~visit
+  local.get $0
+  i32.load
+  local.tee $2
+  if
+   local.get $2
+   local.get $1
+   call $~lib/rt/itcms/__visit
+  end
+ )
+ (func $~lib/object/Object~visit (param $0 i32) (param $1 i32)
+ )
+ (func $~lib/function/FirstClassFunctionBase#get:_env (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=4
+ )
+ (func $~lib/function/FirstClassFunctionBase~visit (param $0 i32) (param $1 i32)
+  local.get $0
+  local.get $1
+  call $~lib/object/Object~visit
+  local.get $0
+  local.get $1
+  call $~lib/function/FirstClassFunctionBase#__visit
+ )
+ (func $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:_env (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=4
+ )
+ (func $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>~visit (param $0 i32) (param $1 i32)
+  local.get $0
+  local.get $1
+  call $~lib/object/Object~visit
+  local.get $0
+  local.get $1
+  call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#__visit
+ )
+ (func $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:_env (param $this i32) (result i32)
+  local.get $this
+  i32.load offset=4
+ )
+ (func $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>~visit (param $0 i32) (param $1 i32)
+  local.get $0
+  local.get $1
+  call $~lib/object/Object~visit
+  local.get $0
+  local.get $1
+  call $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#__visit
+ )
+ (func $~lib/rt/__visit_members (param $0 i32) (param $1 i32)
+  block $invalid
+   block $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>
+    block $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>
+     block $~lib/function/FirstClassFunctionBase
+      block $~lib/arraybuffer/ArrayBufferView
+       block $~lib/string/String
+        block $~lib/arraybuffer/ArrayBuffer
+         block $~lib/object/Object
+          local.get $0
+          i32.const 8
+          i32.sub
+          i32.load
+          br_table $~lib/object/Object $~lib/arraybuffer/ArrayBuffer $~lib/string/String $~lib/arraybuffer/ArrayBufferView $~lib/function/FirstClassFunctionBase $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void> $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void> $invalid
+         end
+         return
+        end
+        return
+       end
+       return
+      end
+      local.get $0
+      local.get $1
+      call $~lib/arraybuffer/ArrayBufferView~visit
+      return
+     end
+     local.get $0
+     local.get $1
+     call $~lib/function/FirstClassFunctionBase~visit
+     return
+    end
+    local.get $0
+    local.get $1
+    call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>~visit
+    return
+   end
+   local.get $0
+   local.get $1
+   call $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>~visit
+   return
+  end
+  unreachable
+ )
+ (func $~start
+  call $start:first-class-function
+ )
+ (func $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  global.get $~lib/memory/__data_end
+  i32.lt_s
+  if
+   i32.const 33360
+   i32.const 33408
+   i32.const 1
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $~lib/function/FirstClassFunctionBase#constructor (param $this i32) (param $index i32) (param $env i32) (result i32)
+  (local $3 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i64.const 0
+  i64.store
+  local.get $this
+  i32.eqz
+  if
+   global.get $~lib/memory/__stack_pointer
+   i32.const 8
+   i32.const 4
+   call $~lib/rt/itcms/__new
+   local.tee $this
+   i32.store
+  end
+  local.get $this
+  local.set $3
+  global.get $~lib/memory/__stack_pointer
+  local.get $3
+  i32.store offset=4
+  local.get $3
+  i32.const 0
+  call $~lib/function/FirstClassFunctionBase#set:_index
+  local.get $this
+  local.set $3
+  global.get $~lib/memory/__stack_pointer
+  local.get $3
+  i32.store offset=4
+  local.get $3
+  i32.const 0
+  call $~lib/function/FirstClassFunctionBase#set:_env
+  local.get $this
+  local.set $3
+  global.get $~lib/memory/__stack_pointer
+  local.get $3
+  i32.store offset=4
+  local.get $3
+  local.get $index
+  call $~lib/function/FirstClassFunctionBase#set:_index
+  local.get $this
+  local.set $3
+  global.get $~lib/memory/__stack_pointer
+  local.get $3
+  i32.store offset=4
+  local.get $3
+  local.get $env
+  call $~lib/function/FirstClassFunctionBase#set:_env
+  local.get $this
+  local.set $3
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+  local.get $3
+ )
+ (func $start:first-class-function~anonymous|0 (result i32)
+  (local $fn i32)
+  (local $1 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i64.const 0
+  i64.store
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.const 1
+  i32.const 0
+  call $~lib/function/FirstClassFunctionBase#constructor
+  local.tee $fn
+  i32.store
+  i32.const 0
+  i32.const 2
+  i32.const 0
+  call $~lib/function/FirstClassFunctionBase#constructor
+  drop
+  local.get $fn
+  local.set $1
+  global.get $~lib/memory/__stack_pointer
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:index
+  i32.const 0
+  i32.ne
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 7
+   i32.const 3
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $fn
+  local.set $1
+  global.get $~lib/memory/__stack_pointer
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  i32.const 1234
+  i32.const 1
+  global.set $~argumentsLength
+  local.get $fn
+  i32.load
+  call_indirect (type $0)
+  local.get $fn
+  local.set $1
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+  local.get $1
+  return
+ )
+ (func $start:first-class-function
+  (local $0 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.store
+  memory.size
+  i32.const 16
+  i32.shl
+  global.get $~lib/memory/__heap_base
+  i32.sub
+  i32.const 1
+  i32.shr_u
+  global.set $~lib/rt/itcms/threshold
+  i32.const 224
+  call $~lib/rt/itcms/initLazy
+  global.set $~lib/rt/itcms/pinSpace
+  i32.const 256
+  call $~lib/rt/itcms/initLazy
+  global.set $~lib/rt/itcms/toSpace
+  i32.const 400
+  call $~lib/rt/itcms/initLazy
+  global.set $~lib/rt/itcms/fromSpace
+  i32.const 0
+  global.set $~argumentsLength
+  global.get $first-class-function/foo
+  i32.load
+  call_indirect (type $4)
+  global.set $first-class-function/fn1
+  call $~lib/rt/itcms/__collect
+  global.get $first-class-function/fn1
+  local.set $0
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store
+  local.get $0
+  i32.const 1234
+  i32.const 1
+  global.set $~argumentsLength
+  global.get $first-class-function/fn1
+  i32.load
+  call_indirect (type $0)
+  global.get $first-class-function/fn1
+  local.set $0
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store
+  local.get $0
+  i32.const 1234
+  i32.const 1
+  global.set $~argumentsLength
+  global.get $first-class-function/fn1
+  i32.load
+  call_indirect (type $0)
+  i32.const 0
+  global.set $~argumentsLength
+  global.get $first-class-function/foo
+  i32.load
+  call_indirect (type $4)
+  global.set $first-class-function/fn2
+  global.get $first-class-function/fn1
+  global.get $first-class-function/fn2
+  i32.ne
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 19
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $first-class-function/fn1
+  local.set $0
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store
+  local.get $0
+  call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:index
+  global.get $first-class-function/fn2
+  local.set $0
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store
+  local.get $0
+  call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:index
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 20
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+ (func $~lib/function/FirstClassFunctionBase#__visit (param $this i32) (param $cookie i32)
+  (local $2 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.store
+  local.get $this
+  local.set $2
+  global.get $~lib/memory/__stack_pointer
+  local.get $2
+  i32.store
+  local.get $2
+  call $~lib/function/FirstClassFunctionBase#get:_env
+  local.get $cookie
+  call $~lib/rt/itcms/__visit
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+ (func $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#__visit (param $this i32) (param $cookie i32)
+  (local $2 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.store
+  local.get $this
+  local.set $2
+  global.get $~lib/memory/__stack_pointer
+  local.get $2
+  i32.store
+  local.get $2
+  call $~lib/function/Function<%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:_env
+  local.get $cookie
+  call $~lib/rt/itcms/__visit
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+ (func $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#__visit (param $this i32) (param $cookie i32)
+  (local $2 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  call $~stack_check
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.store
+  local.get $this
+  local.set $2
+  global.get $~lib/memory/__stack_pointer
+  local.get $2
+  i32.store
+  local.get $2
+  call $~lib/function/Function<%28%29=>%28env:~lib/function/FirstClassFunctionBase%2Ci32%29=>void>#get:_env
+  local.get $cookie
+  call $~lib/rt/itcms/__visit
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+)
diff --git a/tests/compiler/first-class-function.json b/tests/compiler/first-class-function.json
new file mode 100644
index 0000000000..1bdd02b1be
--- /dev/null
+++ b/tests/compiler/first-class-function.json
@@ -0,0 +1,4 @@
+{
+  "asc_flags": [
+  ]
+}
diff --git a/tests/compiler/first-class-function.release.wat b/tests/compiler/first-class-function.release.wat
new file mode 100644
index 0000000000..13039f8148
--- /dev/null
+++ b/tests/compiler/first-class-function.release.wat
@@ -0,0 +1,1720 @@
+(module
+ (type $0 (func (param i32 i32)))
+ (type $1 (func (result i32)))
+ (type $2 (func))
+ (type $3 (func (param i32)))
+ (type $4 (func (param i32) (result i32)))
+ (type $5 (func (param i32 i32 i32 i32)))
+ (type $6 (func (param i32 i32 i64)))
+ (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
+ (global $~lib/rt/itcms/total (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/threshold (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/state (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/visitCount (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/pinSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/iter (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/toSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/white (mut i32) (i32.const 0))
+ (global $~lib/rt/itcms/fromSpace (mut i32) (i32.const 0))
+ (global $~lib/rt/tlsf/ROOT (mut i32) (i32.const 0))
+ (global $first-class-function/fn1 (mut i32) (i32.const 0))
+ (global $first-class-function/fn2 (mut i32) (i32.const 0))
+ (global $~lib/memory/__stack_pointer (mut i32) (i32.const 34352))
+ (memory $0 1)
+ (data $0 (i32.const 1036) "L")
+ (data $0.1 (i32.const 1048) "\02\00\00\00.\00\00\00f\00i\00r\00s\00t\00-\00c\00l\00a\00s\00s\00-\00f\00u\00n\00c\00t\00i\00o\00n\00.\00t\00s")
+ (data $1 (i32.const 1116) "<")
+ (data $1.1 (i32.const 1128) "\02\00\00\00(\00\00\00A\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e")
+ (data $2 (i32.const 1180) "<")
+ (data $2.1 (i32.const 1192) "\02\00\00\00 \00\00\00~\00l\00i\00b\00/\00r\00t\00/\00i\00t\00c\00m\00s\00.\00t\00s")
+ (data $5 (i32.const 1308) "<")
+ (data $5.1 (i32.const 1320) "\02\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e")
+ (data $6 (i32.const 1372) ",")
+ (data $6.1 (i32.const 1384) "\02\00\00\00\14\00\00\00~\00l\00i\00b\00/\00r\00t\00.\00t\00s")
+ (data $8 (i32.const 1452) "<")
+ (data $8.1 (i32.const 1464) "\02\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00t\00l\00s\00f\00.\00t\00s")
+ (data $9 (i32.const 1516) "\1c")
+ (data $9.1 (i32.const 1528) "\06\00\00\00\08\00\00\00\03")
+ (data $10 (i32.const 1552) "\07\00\00\00 \00\00\00 \00\00\00 ")
+ (table $0 4 4 funcref)
+ (elem $0 (i32.const 1) $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|0 $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|0 $start:first-class-function~anonymous|0)
+ (export "memory" (memory $0))
+ (start $~start)
+ (func $start:first-class-function~anonymous|0~start:first-class-function~anonymous|0|anonymous|0 (param $0 i32) (param $1 i32)
+ )
+ (func $~lib/rt/itcms/visitRoots
+  (local $0 i32)
+  (local $1 i32)
+  global.get $first-class-function/fn1
+  local.tee $0
+  if
+   local.get $0
+   call $~lib/rt/itcms/__visit
+  end
+  global.get $first-class-function/fn2
+  local.tee $0
+  if
+   local.get $0
+   call $~lib/rt/itcms/__visit
+  end
+  i32.const 1328
+  call $~lib/rt/itcms/__visit
+  i32.const 1136
+  call $~lib/rt/itcms/__visit
+  global.get $~lib/rt/itcms/pinSpace
+  local.tee $1
+  i32.load offset=4
+  i32.const -4
+  i32.and
+  local.set $0
+  loop $while-continue|0
+   local.get $0
+   local.get $1
+   i32.ne
+   if
+    local.get $0
+    i32.load offset=4
+    i32.const 3
+    i32.and
+    i32.const 3
+    i32.ne
+    if
+     i32.const 0
+     i32.const 1200
+     i32.const 160
+     i32.const 16
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    i32.const 20
+    i32.add
+    call $~lib/rt/__visit_members
+    local.get $0
+    i32.load offset=4
+    i32.const -4
+    i32.and
+    local.set $0
+    br $while-continue|0
+   end
+  end
+ )
+ (func $~lib/rt/itcms/__visit (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  local.get $0
+  i32.eqz
+  if
+   return
+  end
+  global.get $~lib/rt/itcms/white
+  local.get $0
+  i32.const 20
+  i32.sub
+  local.tee $1
+  i32.load offset=4
+  i32.const 3
+  i32.and
+  i32.eq
+  if
+   local.get $1
+   global.get $~lib/rt/itcms/iter
+   i32.eq
+   if
+    local.get $1
+    i32.load offset=8
+    local.tee $0
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 1200
+     i32.const 148
+     i32.const 30
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    global.set $~lib/rt/itcms/iter
+   end
+   block $__inlined_func$~lib/rt/itcms/Object#unlink$122
+    local.get $1
+    i32.load offset=4
+    i32.const -4
+    i32.and
+    local.tee $0
+    i32.eqz
+    if
+     local.get $1
+     i32.load offset=8
+     i32.eqz
+     local.get $1
+     i32.const 34352
+     i32.lt_u
+     i32.and
+     i32.eqz
+     if
+      i32.const 0
+      i32.const 1200
+      i32.const 128
+      i32.const 18
+      call $~lib/builtins/abort
+      unreachable
+     end
+     br $__inlined_func$~lib/rt/itcms/Object#unlink$122
+    end
+    local.get $1
+    i32.load offset=8
+    local.tee $2
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 1200
+     i32.const 132
+     i32.const 16
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    local.get $2
+    i32.store offset=8
+    local.get $2
+    local.get $0
+    local.get $2
+    i32.load offset=4
+    i32.const 3
+    i32.and
+    i32.or
+    i32.store offset=4
+   end
+   global.get $~lib/rt/itcms/toSpace
+   local.set $2
+   local.get $1
+   i32.load offset=12
+   local.tee $0
+   i32.const 2
+   i32.le_u
+   if (result i32)
+    i32.const 1
+   else
+    local.get $0
+    i32.const 1552
+    i32.load
+    i32.gt_u
+    if
+     i32.const 1328
+     i32.const 1392
+     i32.const 21
+     i32.const 28
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    i32.const 2
+    i32.shl
+    i32.const 1556
+    i32.add
+    i32.load
+    i32.const 32
+    i32.and
+   end
+   local.set $3
+   local.get $2
+   i32.load offset=8
+   local.set $0
+   local.get $1
+   global.get $~lib/rt/itcms/white
+   i32.eqz
+   i32.const 2
+   local.get $3
+   select
+   local.get $2
+   i32.or
+   i32.store offset=4
+   local.get $1
+   local.get $0
+   i32.store offset=8
+   local.get $0
+   local.get $1
+   local.get $0
+   i32.load offset=4
+   i32.const 3
+   i32.and
+   i32.or
+   i32.store offset=4
+   local.get $2
+   local.get $1
+   i32.store offset=8
+   global.get $~lib/rt/itcms/visitCount
+   i32.const 1
+   i32.add
+   global.set $~lib/rt/itcms/visitCount
+  end
+ )
+ (func $~lib/rt/tlsf/removeBlock (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  local.get $1
+  i32.load
+  local.tee $3
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 268
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const -4
+  i32.and
+  local.tee $3
+  i32.const 12
+  i32.lt_u
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 270
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const 256
+  i32.lt_u
+  if (result i32)
+   local.get $3
+   i32.const 4
+   i32.shr_u
+  else
+   i32.const 31
+   i32.const 1073741820
+   local.get $3
+   local.get $3
+   i32.const 1073741820
+   i32.ge_u
+   select
+   local.tee $3
+   i32.clz
+   i32.sub
+   local.tee $4
+   i32.const 7
+   i32.sub
+   local.set $2
+   local.get $3
+   local.get $4
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 16
+   i32.xor
+  end
+  local.tee $3
+  i32.const 16
+  i32.lt_u
+  local.get $2
+  i32.const 23
+  i32.lt_u
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 284
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load offset=8
+  local.set $5
+  local.get $1
+  i32.load offset=4
+  local.tee $4
+  if
+   local.get $4
+   local.get $5
+   i32.store offset=8
+  end
+  local.get $5
+  if
+   local.get $5
+   local.get $4
+   i32.store offset=4
+  end
+  local.get $1
+  local.get $0
+  local.get $2
+  i32.const 4
+  i32.shl
+  local.get $3
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  local.tee $1
+  i32.load offset=96
+  i32.eq
+  if
+   local.get $1
+   local.get $5
+   i32.store offset=96
+   local.get $5
+   i32.eqz
+   if
+    local.get $0
+    local.get $2
+    i32.const 2
+    i32.shl
+    i32.add
+    local.tee $1
+    i32.load offset=4
+    i32.const -2
+    local.get $3
+    i32.rotl
+    i32.and
+    local.set $3
+    local.get $1
+    local.get $3
+    i32.store offset=4
+    local.get $3
+    i32.eqz
+    if
+     local.get $0
+     local.get $0
+     i32.load
+     i32.const -2
+     local.get $2
+     i32.rotl
+     i32.and
+     i32.store
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/insertBlock (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  local.get $1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 201
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load
+  local.tee $3
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 203
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 4
+  i32.add
+  local.get $1
+  i32.load
+  i32.const -4
+  i32.and
+  i32.add
+  local.tee $4
+  i32.load
+  local.tee $2
+  i32.const 1
+  i32.and
+  if
+   local.get $0
+   local.get $4
+   call $~lib/rt/tlsf/removeBlock
+   local.get $1
+   local.get $3
+   i32.const 4
+   i32.add
+   local.get $2
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $3
+   i32.store
+   local.get $1
+   i32.const 4
+   i32.add
+   local.get $1
+   i32.load
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $4
+   i32.load
+   local.set $2
+  end
+  local.get $3
+  i32.const 2
+  i32.and
+  if
+   local.get $1
+   i32.const 4
+   i32.sub
+   i32.load
+   local.tee $1
+   i32.load
+   local.tee $6
+   i32.const 1
+   i32.and
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 1472
+    i32.const 221
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $0
+   local.get $1
+   call $~lib/rt/tlsf/removeBlock
+   local.get $1
+   local.get $6
+   i32.const 4
+   i32.add
+   local.get $3
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $3
+   i32.store
+  end
+  local.get $4
+  local.get $2
+  i32.const 2
+  i32.or
+  i32.store
+  local.get $3
+  i32.const -4
+  i32.and
+  local.tee $2
+  i32.const 12
+  i32.lt_u
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 233
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $4
+  local.get $1
+  i32.const 4
+  i32.add
+  local.get $2
+  i32.add
+  i32.ne
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 234
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $4
+  i32.const 4
+  i32.sub
+  local.get $1
+  i32.store
+  local.get $2
+  i32.const 256
+  i32.lt_u
+  if (result i32)
+   local.get $2
+   i32.const 4
+   i32.shr_u
+  else
+   i32.const 31
+   i32.const 1073741820
+   local.get $2
+   local.get $2
+   i32.const 1073741820
+   i32.ge_u
+   select
+   local.tee $2
+   i32.clz
+   i32.sub
+   local.tee $3
+   i32.const 7
+   i32.sub
+   local.set $5
+   local.get $2
+   local.get $3
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 16
+   i32.xor
+  end
+  local.tee $2
+  i32.const 16
+  i32.lt_u
+  local.get $5
+  i32.const 23
+  i32.lt_u
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 251
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $5
+  i32.const 4
+  i32.shl
+  local.get $2
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=96
+  local.set $3
+  local.get $1
+  i32.const 0
+  i32.store offset=4
+  local.get $1
+  local.get $3
+  i32.store offset=8
+  local.get $3
+  if
+   local.get $3
+   local.get $1
+   i32.store offset=4
+  end
+  local.get $0
+  local.get $5
+  i32.const 4
+  i32.shl
+  local.get $2
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $1
+  i32.store offset=96
+  local.get $0
+  local.get $0
+  i32.load
+  i32.const 1
+  local.get $5
+  i32.shl
+  i32.or
+  i32.store
+  local.get $0
+  local.get $5
+  i32.const 2
+  i32.shl
+  i32.add
+  local.tee $0
+  local.get $0
+  i32.load offset=4
+  i32.const 1
+  local.get $2
+  i32.shl
+  i32.or
+  i32.store offset=4
+ )
+ (func $~lib/rt/tlsf/addMemory (param $0 i32) (param $1 i32) (param $2 i64)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  local.get $2
+  local.get $1
+  i64.extend_i32_u
+  i64.lt_u
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 382
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 19
+  i32.add
+  i32.const -16
+  i32.and
+  i32.const 4
+  i32.sub
+  local.set $1
+  local.get $0
+  i32.load offset=1568
+  local.tee $3
+  if
+   local.get $3
+   i32.const 4
+   i32.add
+   local.get $1
+   i32.gt_u
+   if
+    i32.const 0
+    i32.const 1472
+    i32.const 389
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $3
+   local.get $1
+   i32.const 16
+   i32.sub
+   local.tee $5
+   i32.eq
+   if
+    local.get $3
+    i32.load
+    local.set $4
+    local.get $5
+    local.set $1
+   end
+  else
+   local.get $0
+   i32.const 1572
+   i32.add
+   local.get $1
+   i32.gt_u
+   if
+    i32.const 0
+    i32.const 1472
+    i32.const 402
+    i32.const 5
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  local.get $2
+  i32.wrap_i64
+  i32.const -16
+  i32.and
+  local.get $1
+  i32.sub
+  local.tee $3
+  i32.const 20
+  i32.lt_u
+  if
+   return
+  end
+  local.get $1
+  local.get $4
+  i32.const 2
+  i32.and
+  local.get $3
+  i32.const 8
+  i32.sub
+  local.tee $3
+  i32.const 1
+  i32.or
+  i32.or
+  i32.store
+  local.get $1
+  i32.const 0
+  i32.store offset=4
+  local.get $1
+  i32.const 0
+  i32.store offset=8
+  local.get $1
+  i32.const 4
+  i32.add
+  local.get $3
+  i32.add
+  local.tee $3
+  i32.const 2
+  i32.store
+  local.get $0
+  local.get $3
+  i32.store offset=1568
+  local.get $0
+  local.get $1
+  call $~lib/rt/tlsf/insertBlock
+ )
+ (func $~lib/rt/tlsf/initialize
+  (local $0 i32)
+  (local $1 i32)
+  memory.size
+  local.tee $1
+  i32.const 0
+  i32.le_s
+  if (result i32)
+   i32.const 1
+   local.get $1
+   i32.sub
+   memory.grow
+   i32.const 0
+   i32.lt_s
+  else
+   i32.const 0
+  end
+  if
+   unreachable
+  end
+  i32.const 34352
+  i32.const 0
+  i32.store
+  i32.const 35920
+  i32.const 0
+  i32.store
+  loop $for-loop|0
+   local.get $0
+   i32.const 23
+   i32.lt_u
+   if
+    local.get $0
+    i32.const 2
+    i32.shl
+    i32.const 34352
+    i32.add
+    i32.const 0
+    i32.store offset=4
+    i32.const 0
+    local.set $1
+    loop $for-loop|1
+     local.get $1
+     i32.const 16
+     i32.lt_u
+     if
+      local.get $0
+      i32.const 4
+      i32.shl
+      local.get $1
+      i32.add
+      i32.const 2
+      i32.shl
+      i32.const 34352
+      i32.add
+      i32.const 0
+      i32.store offset=96
+      local.get $1
+      i32.const 1
+      i32.add
+      local.set $1
+      br $for-loop|1
+     end
+    end
+    local.get $0
+    i32.const 1
+    i32.add
+    local.set $0
+    br $for-loop|0
+   end
+  end
+  i32.const 34352
+  i32.const 35924
+  memory.size
+  i64.extend_i32_s
+  i64.const 16
+  i64.shl
+  call $~lib/rt/tlsf/addMemory
+  i32.const 34352
+  global.set $~lib/rt/tlsf/ROOT
+ )
+ (func $~lib/rt/itcms/step (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  block $break|0
+   block $case2|0
+    block $case1|0
+     block $case0|0
+      global.get $~lib/rt/itcms/state
+      br_table $case0|0 $case1|0 $case2|0 $break|0
+     end
+     i32.const 1
+     global.set $~lib/rt/itcms/state
+     i32.const 0
+     global.set $~lib/rt/itcms/visitCount
+     call $~lib/rt/itcms/visitRoots
+     global.get $~lib/rt/itcms/toSpace
+     global.set $~lib/rt/itcms/iter
+     global.get $~lib/rt/itcms/visitCount
+     return
+    end
+    global.get $~lib/rt/itcms/white
+    i32.eqz
+    local.set $1
+    global.get $~lib/rt/itcms/iter
+    i32.load offset=4
+    i32.const -4
+    i32.and
+    local.set $0
+    loop $while-continue|1
+     local.get $0
+     global.get $~lib/rt/itcms/toSpace
+     i32.ne
+     if
+      local.get $0
+      global.set $~lib/rt/itcms/iter
+      local.get $1
+      local.get $0
+      i32.load offset=4
+      local.tee $2
+      i32.const 3
+      i32.and
+      i32.ne
+      if
+       local.get $0
+       local.get $2
+       i32.const -4
+       i32.and
+       local.get $1
+       i32.or
+       i32.store offset=4
+       i32.const 0
+       global.set $~lib/rt/itcms/visitCount
+       local.get $0
+       i32.const 20
+       i32.add
+       call $~lib/rt/__visit_members
+       global.get $~lib/rt/itcms/visitCount
+       return
+      end
+      local.get $0
+      i32.load offset=4
+      i32.const -4
+      i32.and
+      local.set $0
+      br $while-continue|1
+     end
+    end
+    i32.const 0
+    global.set $~lib/rt/itcms/visitCount
+    call $~lib/rt/itcms/visitRoots
+    global.get $~lib/rt/itcms/toSpace
+    global.get $~lib/rt/itcms/iter
+    i32.load offset=4
+    i32.const -4
+    i32.and
+    i32.eq
+    if
+     global.get $~lib/memory/__stack_pointer
+     local.set $0
+     loop $while-continue|0
+      local.get $0
+      i32.const 34352
+      i32.lt_u
+      if
+       local.get $0
+       i32.load
+       call $~lib/rt/itcms/__visit
+       local.get $0
+       i32.const 4
+       i32.add
+       local.set $0
+       br $while-continue|0
+      end
+     end
+     global.get $~lib/rt/itcms/iter
+     i32.load offset=4
+     i32.const -4
+     i32.and
+     local.set $0
+     loop $while-continue|2
+      local.get $0
+      global.get $~lib/rt/itcms/toSpace
+      i32.ne
+      if
+       local.get $1
+       local.get $0
+       i32.load offset=4
+       local.tee $2
+       i32.const 3
+       i32.and
+       i32.ne
+       if
+        local.get $0
+        local.get $2
+        i32.const -4
+        i32.and
+        local.get $1
+        i32.or
+        i32.store offset=4
+        local.get $0
+        i32.const 20
+        i32.add
+        call $~lib/rt/__visit_members
+       end
+       local.get $0
+       i32.load offset=4
+       i32.const -4
+       i32.and
+       local.set $0
+       br $while-continue|2
+      end
+     end
+     global.get $~lib/rt/itcms/fromSpace
+     local.set $0
+     global.get $~lib/rt/itcms/toSpace
+     global.set $~lib/rt/itcms/fromSpace
+     local.get $0
+     global.set $~lib/rt/itcms/toSpace
+     local.get $1
+     global.set $~lib/rt/itcms/white
+     local.get $0
+     i32.load offset=4
+     i32.const -4
+     i32.and
+     global.set $~lib/rt/itcms/iter
+     i32.const 2
+     global.set $~lib/rt/itcms/state
+    end
+    global.get $~lib/rt/itcms/visitCount
+    return
+   end
+   global.get $~lib/rt/itcms/iter
+   local.tee $0
+   global.get $~lib/rt/itcms/toSpace
+   i32.ne
+   if
+    local.get $0
+    i32.load offset=4
+    local.tee $1
+    i32.const -4
+    i32.and
+    global.set $~lib/rt/itcms/iter
+    global.get $~lib/rt/itcms/white
+    i32.eqz
+    local.get $1
+    i32.const 3
+    i32.and
+    i32.ne
+    if
+     i32.const 0
+     i32.const 1200
+     i32.const 229
+     i32.const 20
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    i32.const 34352
+    i32.lt_u
+    if
+     local.get $0
+     i32.const 0
+     i32.store offset=4
+     local.get $0
+     i32.const 0
+     i32.store offset=8
+    else
+     global.get $~lib/rt/itcms/total
+     local.get $0
+     i32.load
+     i32.const -4
+     i32.and
+     i32.const 4
+     i32.add
+     i32.sub
+     global.set $~lib/rt/itcms/total
+     local.get $0
+     i32.const 4
+     i32.add
+     local.tee $0
+     i32.const 34352
+     i32.ge_u
+     if
+      global.get $~lib/rt/tlsf/ROOT
+      i32.eqz
+      if
+       call $~lib/rt/tlsf/initialize
+      end
+      global.get $~lib/rt/tlsf/ROOT
+      local.set $1
+      local.get $0
+      i32.const 4
+      i32.sub
+      local.set $2
+      local.get $0
+      i32.const 15
+      i32.and
+      i32.const 1
+      local.get $0
+      select
+      if (result i32)
+       i32.const 1
+      else
+       local.get $2
+       i32.load
+       i32.const 1
+       i32.and
+      end
+      if
+       i32.const 0
+       i32.const 1472
+       i32.const 562
+       i32.const 3
+       call $~lib/builtins/abort
+       unreachable
+      end
+      local.get $2
+      local.get $2
+      i32.load
+      i32.const 1
+      i32.or
+      i32.store
+      local.get $1
+      local.get $2
+      call $~lib/rt/tlsf/insertBlock
+     end
+    end
+    i32.const 10
+    return
+   end
+   global.get $~lib/rt/itcms/toSpace
+   local.tee $0
+   local.get $0
+   i32.store offset=4
+   local.get $0
+   local.get $0
+   i32.store offset=8
+   i32.const 0
+   global.set $~lib/rt/itcms/state
+  end
+  i32.const 0
+ )
+ (func $~lib/rt/tlsf/searchBlock (param $0 i32) (result i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  i32.load offset=4
+  i32.const -2
+  i32.and
+  local.tee $1
+  if (result i32)
+   local.get $0
+   local.get $1
+   i32.ctz
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=96
+  else
+   local.get $0
+   i32.load
+   i32.const -2
+   i32.and
+   local.tee $1
+   if (result i32)
+    local.get $0
+    local.get $1
+    i32.ctz
+    local.tee $2
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=4
+    local.tee $1
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 1472
+     i32.const 347
+     i32.const 18
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    local.get $1
+    i32.ctz
+    local.get $2
+    i32.const 4
+    i32.shl
+    i32.add
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=96
+   else
+    i32.const 0
+   end
+  end
+ )
+ (func $~lib/rt/itcms/__new (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  global.get $~lib/rt/itcms/total
+  global.get $~lib/rt/itcms/threshold
+  i32.ge_u
+  if
+   block $__inlined_func$~lib/rt/itcms/interrupt$69
+    i32.const 2048
+    local.set $0
+    loop $do-loop|0
+     local.get $0
+     call $~lib/rt/itcms/step
+     i32.sub
+     local.set $0
+     global.get $~lib/rt/itcms/state
+     i32.eqz
+     if
+      global.get $~lib/rt/itcms/total
+      i64.extend_i32_u
+      i64.const 200
+      i64.mul
+      i64.const 100
+      i64.div_u
+      i32.wrap_i64
+      i32.const 1024
+      i32.add
+      global.set $~lib/rt/itcms/threshold
+      br $__inlined_func$~lib/rt/itcms/interrupt$69
+     end
+     local.get $0
+     i32.const 0
+     i32.gt_s
+     br_if $do-loop|0
+    end
+    global.get $~lib/rt/itcms/total
+    local.tee $0
+    local.get $0
+    global.get $~lib/rt/itcms/threshold
+    i32.sub
+    i32.const 1024
+    i32.lt_u
+    i32.const 10
+    i32.shl
+    i32.add
+    global.set $~lib/rt/itcms/threshold
+   end
+  end
+  global.get $~lib/rt/tlsf/ROOT
+  i32.eqz
+  if
+   call $~lib/rt/tlsf/initialize
+  end
+  global.get $~lib/rt/tlsf/ROOT
+  local.tee $1
+  call $~lib/rt/tlsf/searchBlock
+  local.tee $0
+  i32.eqz
+  if
+   memory.size
+   local.tee $0
+   i32.const 4
+   local.get $1
+   i32.load offset=1568
+   local.get $0
+   i32.const 16
+   i32.shl
+   i32.const 4
+   i32.sub
+   i32.ne
+   i32.shl
+   i32.const 65563
+   i32.add
+   i32.const -65536
+   i32.and
+   i32.const 16
+   i32.shr_u
+   local.tee $2
+   local.get $0
+   local.get $2
+   i32.gt_s
+   select
+   memory.grow
+   i32.const 0
+   i32.lt_s
+   if
+    local.get $2
+    memory.grow
+    i32.const 0
+    i32.lt_s
+    if
+     unreachable
+    end
+   end
+   local.get $1
+   local.get $0
+   i32.const 16
+   i32.shl
+   memory.size
+   i64.extend_i32_s
+   i64.const 16
+   i64.shl
+   call $~lib/rt/tlsf/addMemory
+   local.get $1
+   call $~lib/rt/tlsf/searchBlock
+   local.tee $0
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 1472
+    i32.const 499
+    i32.const 16
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  local.get $0
+  i32.load
+  i32.const -4
+  i32.and
+  i32.const 28
+  i32.lt_u
+  if
+   i32.const 0
+   i32.const 1472
+   i32.const 501
+   i32.const 14
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  local.get $0
+  call $~lib/rt/tlsf/removeBlock
+  local.get $0
+  i32.load
+  local.tee $2
+  i32.const -4
+  i32.and
+  i32.const 28
+  i32.sub
+  local.tee $3
+  i32.const 16
+  i32.ge_u
+  if
+   local.get $0
+   local.get $2
+   i32.const 2
+   i32.and
+   i32.const 28
+   i32.or
+   i32.store
+   local.get $0
+   i32.const 32
+   i32.add
+   local.tee $2
+   local.get $3
+   i32.const 4
+   i32.sub
+   i32.const 1
+   i32.or
+   i32.store
+   local.get $1
+   local.get $2
+   call $~lib/rt/tlsf/insertBlock
+  else
+   local.get $0
+   local.get $2
+   i32.const -2
+   i32.and
+   i32.store
+   local.get $0
+   i32.const 4
+   i32.add
+   local.get $0
+   i32.load
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $1
+   local.get $1
+   i32.load
+   i32.const -3
+   i32.and
+   i32.store
+  end
+  local.get $0
+  i32.const 4
+  i32.store offset=12
+  local.get $0
+  i32.const 8
+  i32.store offset=16
+  global.get $~lib/rt/itcms/fromSpace
+  local.tee $1
+  i32.load offset=8
+  local.set $2
+  local.get $0
+  local.get $1
+  global.get $~lib/rt/itcms/white
+  i32.or
+  i32.store offset=4
+  local.get $0
+  local.get $2
+  i32.store offset=8
+  local.get $2
+  local.get $0
+  local.get $2
+  i32.load offset=4
+  i32.const 3
+  i32.and
+  i32.or
+  i32.store offset=4
+  local.get $1
+  local.get $0
+  i32.store offset=8
+  global.get $~lib/rt/itcms/total
+  local.get $0
+  i32.load
+  i32.const -4
+  i32.and
+  i32.const 4
+  i32.add
+  i32.add
+  global.set $~lib/rt/itcms/total
+  local.get $0
+  i32.const 20
+  i32.add
+  local.tee $0
+  i64.const 0
+  i64.store align=1
+  local.get $0
+ )
+ (func $~lib/rt/__visit_members (param $0 i32)
+  (local $1 i32)
+  block $folding-inner0
+   block $invalid
+    block $~lib/arraybuffer/ArrayBufferView
+     block $~lib/string/String
+      block $~lib/arraybuffer/ArrayBuffer
+       block $~lib/object/Object
+        local.get $0
+        i32.const 8
+        i32.sub
+        i32.load
+        br_table $~lib/object/Object $~lib/arraybuffer/ArrayBuffer $~lib/string/String $~lib/arraybuffer/ArrayBufferView $folding-inner0 $folding-inner0 $folding-inner0 $invalid
+       end
+       return
+      end
+      return
+     end
+     return
+    end
+    local.get $0
+    i32.load
+    local.tee $0
+    if
+     local.get $0
+     call $~lib/rt/itcms/__visit
+    end
+    return
+   end
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  global.get $~lib/memory/__stack_pointer
+  i32.const 1584
+  i32.lt_s
+  if
+   i32.const 34384
+   i32.const 34432
+   i32.const 1
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  local.tee $1
+  i32.const 0
+  i32.store
+  local.get $1
+  local.get $0
+  i32.store
+  local.get $0
+  i32.load offset=4
+  call $~lib/rt/itcms/__visit
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+ (func $~start
+  (local $0 i32)
+  (local $1 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  global.get $~lib/memory/__stack_pointer
+  i32.const 1584
+  i32.lt_s
+  if
+   i32.const 34384
+   i32.const 34432
+   i32.const 1
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  i32.const 0
+  i32.store
+  memory.size
+  i32.const 16
+  i32.shl
+  i32.const 34352
+  i32.sub
+  i32.const 1
+  i32.shr_u
+  global.set $~lib/rt/itcms/threshold
+  i32.const 1252
+  i32.const 1248
+  i32.store
+  i32.const 1256
+  i32.const 1248
+  i32.store
+  i32.const 1248
+  global.set $~lib/rt/itcms/pinSpace
+  i32.const 1284
+  i32.const 1280
+  i32.store
+  i32.const 1288
+  i32.const 1280
+  i32.store
+  i32.const 1280
+  global.set $~lib/rt/itcms/toSpace
+  i32.const 1428
+  i32.const 1424
+  i32.store
+  i32.const 1432
+  i32.const 1424
+  i32.store
+  i32.const 1424
+  global.set $~lib/rt/itcms/fromSpace
+  i32.const 1536
+  i32.load
+  call_indirect (type $1)
+  global.set $first-class-function/fn1
+  global.get $~lib/rt/itcms/state
+  i32.const 0
+  i32.gt_s
+  if
+   loop $while-continue|0
+    global.get $~lib/rt/itcms/state
+    if
+     call $~lib/rt/itcms/step
+     drop
+     br $while-continue|0
+    end
+   end
+  end
+  call $~lib/rt/itcms/step
+  drop
+  loop $while-continue|1
+   global.get $~lib/rt/itcms/state
+   if
+    call $~lib/rt/itcms/step
+    drop
+    br $while-continue|1
+   end
+  end
+  global.get $~lib/rt/itcms/total
+  i64.extend_i32_u
+  i64.const 200
+  i64.mul
+  i64.const 100
+  i64.div_u
+  i32.wrap_i64
+  i32.const 1024
+  i32.add
+  global.set $~lib/rt/itcms/threshold
+  global.get $~lib/memory/__stack_pointer
+  global.get $first-class-function/fn1
+  local.tee $0
+  i32.store
+  local.get $0
+  i32.const 1234
+  local.get $0
+  i32.load
+  call_indirect (type $0)
+  global.get $~lib/memory/__stack_pointer
+  global.get $first-class-function/fn1
+  local.tee $0
+  i32.store
+  local.get $0
+  i32.const 1234
+  global.get $first-class-function/fn1
+  i32.load
+  call_indirect (type $0)
+  i32.const 1536
+  i32.load
+  call_indirect (type $1)
+  global.set $first-class-function/fn2
+  global.get $first-class-function/fn1
+  global.get $first-class-function/fn2
+  i32.eq
+  if
+   i32.const 0
+   i32.const 1056
+   i32.const 19
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  local.tee $0
+  global.get $first-class-function/fn1
+  local.tee $1
+  i32.store
+  local.get $1
+  i32.load
+  local.set $1
+  local.get $0
+  global.get $first-class-function/fn2
+  local.tee $0
+  i32.store
+  local.get $1
+  local.get $0
+  i32.load
+  i32.ne
+  if
+   i32.const 0
+   i32.const 1056
+   i32.const 20
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  i32.const 4
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+ )
+ (func $~lib/function/FirstClassFunctionBase#constructor (param $0 i32) (result i32)
+  (local $1 i32)
+  (local $2 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  global.get $~lib/memory/__stack_pointer
+  i32.const 1584
+  i32.lt_s
+  if
+   i32.const 34384
+   i32.const 34432
+   i32.const 1
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  local.tee $1
+  i64.const 0
+  i64.store
+  local.get $1
+  call $~lib/rt/itcms/__new
+  local.tee $1
+  i32.store
+  global.get $~lib/memory/__stack_pointer
+  local.tee $2
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  i32.const 0
+  i32.store
+  local.get $2
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  i32.const 0
+  i32.store offset=4
+  local.get $2
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  local.get $0
+  i32.store
+  local.get $2
+  local.get $1
+  i32.store offset=4
+  local.get $1
+  i32.const 0
+  i32.store offset=4
+  local.get $2
+  i32.const 8
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+  local.get $1
+ )
+ (func $start:first-class-function~anonymous|0 (result i32)
+  (local $0 i32)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.sub
+  global.set $~lib/memory/__stack_pointer
+  global.get $~lib/memory/__stack_pointer
+  i32.const 1584
+  i32.lt_s
+  if
+   i32.const 34384
+   i32.const 34432
+   i32.const 1
+   i32.const 1
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  local.tee $0
+  i64.const 0
+  i64.store
+  local.get $0
+  i32.const 1
+  call $~lib/function/FirstClassFunctionBase#constructor
+  local.tee $0
+  i32.store
+  i32.const 2
+  call $~lib/function/FirstClassFunctionBase#constructor
+  drop
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store offset=4
+  local.get $0
+  i32.load
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 1056
+   i32.const 7
+   i32.const 3
+   call $~lib/builtins/abort
+   unreachable
+  end
+  global.get $~lib/memory/__stack_pointer
+  local.get $0
+  i32.store offset=4
+  local.get $0
+  i32.const 1234
+  local.get $0
+  i32.load
+  call_indirect (type $0)
+  global.get $~lib/memory/__stack_pointer
+  i32.const 8
+  i32.add
+  global.set $~lib/memory/__stack_pointer
+  local.get $0
+ )
+)
diff --git a/tests/compiler/first-class-function.ts b/tests/compiler/first-class-function.ts
new file mode 100644
index 0000000000..a883053ec8
--- /dev/null
+++ b/tests/compiler/first-class-function.ts
@@ -0,0 +1,20 @@
+let foo = (): experimental_first_class_function<(v: i32) => void> => {
+  let fn = experimental_first_class_function((v: i32): void => {
+    assert(v == 1234);
+  });
+  experimental_first_class_function((v: i32): void => {}); // TODO: suspend binaryen optimized bug?
+
+  assert(fn.index != 0);
+  fn(1234);
+  return fn;
+};
+
+let fn1 = foo();
+__collect();
+fn1(1234);
+fn1(1234);
+
+let fn2 = foo();
+
+assert(fn1 != fn2);
+assert(fn1.index == fn2.index);