Improve type checking

TODO: add better error messages

Author: willemneal

src/program.ts

@@ -2769,6 +2769,11 @@ export class FunctionPrototype extends DeclaredElement {
   lookup(name: string): Element | null {
     return this.parent.lookup(name);
   }
+
+  equals(func: FunctionPrototype): bool {
+    return this.functionTypeNode.equals(func.functionTypeNode) &&
+           TypeNode.arrayEquals(func.typeParameterNodes, this.typeParameterNodes);
+  }
 }
 
 /** A resolved function. */
@@ -3381,7 +3386,7 @@ export class Class extends TypedElement {
   /** Tests if a value of this class type is assignable to a target of the specified class type. */
   isAssignableTo(target: Class): bool {
     var current: Class | null = this;
-    if (target.kind == ElementKind.INTERFACE) {
+    if (target.kind == ElementKind.INTERFACE) { 
       return (<Interface>target).checkClass(this);
     }
     do if (current == target) return true;
@@ -3666,8 +3671,11 @@ export class Interface extends Class { // FIXME
   }
 
   checkClass(_class: Class): bool {
-    return this.methods.reduce<bool>((acc, ifunc) => 
-                  (this.getFunc(_class, ifunc) != null ) && acc, true);
+    return this.methods.reduce<bool>((acc, ifunc) => {
+      let func = this.getFunc(_class, ifunc);
+      if (func == null) return false;
+      return ifunc.equals(func) && acc;
+    }, true);
   }
 
   private getFunc(_class: Class, ifunc: FunctionPrototype): FunctionPrototype | null {

tests/compiler/interface.json renamed to tests/compiler/interface-fail.json

@@ -0,0 +1,96 @@
+(module
+ (type $FUNCSIG$vi (func (param i32)))
+ (type $FUNCSIG$v (func))
+ (type $FUNCSIG$i (func (result i32)))
+ (memory $0 0)
+ (global $~lib/rt/stub/startOffset (mut i32) (i32.const 0))
+ (global $~lib/rt/stub/offset (mut i32) (i32.const 0))
+ (global $interface-fail/aFoo (mut i32) (i32.const 0))
+ (export "memory" (memory $0))
+ (start $start)
+ (func $~lib/rt/stub/maybeGrowMemory (; 0 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  memory.size
+  local.tee $2
+  i32.const 16
+  i32.shl
+  local.tee $1
+  i32.gt_u
+  if
+   local.get $2
+   local.get $0
+   local.get $1
+   i32.sub
+   i32.const 65535
+   i32.add
+   i32.const -65536
+   i32.and
+   i32.const 16
+   i32.shr_u
+   local.tee $1
+   local.get $2
+   local.get $1
+   i32.gt_s
+   select
+   memory.grow
+   i32.const 0
+   i32.lt_s
+   if
+    local.get $1
+    memory.grow
+    i32.const 0
+    i32.lt_s
+    if
+     unreachable
+    end
+   end
+  end
+  local.get $0
+  global.set $~lib/rt/stub/offset
+ )
+ (func $~lib/rt/stub/__alloc (; 1 ;) (type $FUNCSIG$i) (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  global.get $~lib/rt/stub/offset
+  i32.const 16
+  i32.add
+  local.tee $1
+  i32.const 16
+  i32.add
+  call $~lib/rt/stub/maybeGrowMemory
+  local.get $1
+  i32.const 16
+  i32.sub
+  local.tee $0
+  i32.const 16
+  i32.store
+  local.get $0
+  i32.const -1
+  i32.store offset=4
+  local.get $0
+  i32.const 4
+  i32.store offset=8
+  local.get $0
+  i32.const 4
+  i32.store offset=12
+  local.get $1
+ )
+ (func $start (; 2 ;) (type $FUNCSIG$v)
+  (local $0 i32)
+  i32.const 16
+  global.set $~lib/rt/stub/startOffset
+  i32.const 16
+  global.set $~lib/rt/stub/offset
+  call $~lib/rt/stub/__alloc
+  local.tee $0
+  i32.const 41
+  i32.store
+  local.get $0
+  global.set $interface-fail/aFoo
+ )
+ (func $null (; 3 ;) (type $FUNCSIG$v)
+  nop
+ )
+)

tests/compiler/interface-fail.optimized.wat

@@ -0,0 +1,22 @@
+
+interface IFoo {
+  foo(i: i32): i32;
+}
+
+class BadFoo implements IFoo {
+  i: i32 = 41;
+
+  foo(i: i32): string {
+    return "hello";
+  }
+
+  faa(i: i32, i2: i32): i32 {
+    return i + i2;
+  }
+
+}
+
+
+const aFoo: IFoo =  new BadFoo();
+
+