Sema: Nuke NominalTypeDecl::markInvalidGenericSignature()

This would just set the NominalTypeDecl's declared type to
ErrorType, which caused problems elsewhere.

Instead, generalize the logic used for AbstractFunctionDecl.
This correctly wires up the GenericTypeParamDecl's archetypes even
if the signature didn't validate, fixing crashes if the generic
parameters of the type are referenced.

Author: slavapestov

include/swift/AST/Decl.h

@@ -2871,9 +2871,6 @@ class NominalTypeDecl : public TypeDecl, public DeclContext,
     return GenericSig;
   }
 
-  /// Mark generic type signature as invalid.
-  void markInvalidGenericSignature();
-
   /// getDeclaredType - Retrieve the type declared by this entity.
   Type getDeclaredType() const { return DeclaredTy; }
 

lib/AST/Decl.cpp

@@ -1922,13 +1922,6 @@ void NominalTypeDecl::setGenericSignature(GenericSignature *sig) {
   GenericSig = sig;
 }
 
-void NominalTypeDecl::markInvalidGenericSignature() {
-  ASTContext &ctx = getASTContext();
-  overwriteType(ErrorType::get(ctx));
-  if (!getDeclaredType())
-    setDeclaredType(ErrorType::get(ctx));
-}
-
 void NominalTypeDecl::computeType() {
   assert(!hasType() && "Nominal type declaration already has a type");
 

lib/Sema/TypeCheckDecl.cpp

@@ -795,22 +795,24 @@ void TypeChecker::revertGenericParamList(GenericParamList *genericParams) {
   }
 }
 
-static void markInvalidGenericSignature(AbstractFunctionDecl *AFD,
+static void markInvalidGenericSignature(ValueDecl *VD,
                                         TypeChecker &TC) {
-  ArchetypeBuilder builder = TC.createArchetypeBuilder(AFD->getParentModule());
-  auto genericParams = AFD->getGenericParams();
-  
-  // If there is a parent context, add the generic parameters and requirements
-  // from that context.
-  auto dc = AFD->getDeclContext();
-
-  if (dc->isTypeContext())
-    if (auto sig = dc->getGenericSignatureOfContext())
-      builder.addGenericSignature(sig, true);
+  GenericParamList *genericParams;
+  if (auto *AFD = dyn_cast<AbstractFunctionDecl>(VD))
+    genericParams = AFD->getGenericParams();
+  else
+    genericParams = cast<NominalTypeDecl>(VD)->getGenericParams();
 
   // If there aren't any generic parameters at this level, we're done.
-  if (!genericParams)
+  if (genericParams == nullptr)
     return;
+
+  DeclContext *DC = VD->getDeclContext();
+  ArchetypeBuilder builder = TC.createArchetypeBuilder(DC->getParentModule());
+
+  if (DC->isTypeContext())
+    if (auto sig = DC->getGenericSignatureOfContext())
+      builder.addGenericSignature(sig, true);
 
   // Visit each of the generic parameters.
   for (auto param : *genericParams)
@@ -5824,7 +5826,7 @@ void TypeChecker::validateDecl(ValueDecl *D, bool resolveTypeParams) {
 
       // Validate the generic type parameters.
       if (validateGenericTypeSignature(nominal)) {
-        nominal->markInvalidGenericSignature();
+        markInvalidGenericSignature(nominal, *this);
         return;
       }
 

test/Generics/associated_type_typo.swift

@@ -49,11 +49,11 @@ func typoAssoc4<T : P2 where T.Assocp2.assoc : P3>(_: T) { }
 // <rdar://problem/19620340>
 
 func typoFunc1<T : P1>(x: TypoType) { // expected-error{{use of undeclared type 'TypoType'}}
-  let _: T.Assoc -> () = { let _ = $0 }
+  let _: T.Assoc -> () = { let _ = $0 } // expected-error{{'Assoc' is not a member type of 'T'}}
 }
 
 func typoFunc2<T : P1>(x: TypoType, y: T) { // expected-error{{use of undeclared type 'TypoType'}}
-  let _: T.Assoc -> () = { let _ = $0 }
+  let _: T.Assoc -> () = { let _ = $0 } // expected-error{{'Assoc' is not a member type of 'T'}}
 }
 
 func typoFunc3<T : P1>(x: TypoType, y: T.Assoc -> ()) { // expected-error{{use of undeclared type 'TypoType'}}

test/Sema/accessibility.swift

@@ -309,6 +309,7 @@ struct DefaultGeneric<T> {}
 struct DefaultGenericPrivate<T: PrivateProto> {} // expected-error {{generic struct must be declared private because its generic parameter uses a private type}}
 struct DefaultGenericPrivate2<T: PrivateClass> {} // expected-error {{generic struct must be declared private because its generic parameter uses a private type}}
 struct DefaultGenericPrivateReq<T where T == PrivateClass> {} // expected-error {{same-type requirement makes generic parameter 'T' non-generic}}
+// expected-error@-1 {{generic struct must be declared private because its generic requirement uses a private type}}
 struct DefaultGenericPrivateReq2<T where T: PrivateProto> {} // expected-error {{generic struct must be declared private because its generic requirement uses a private type}}
 
 public struct PublicGenericInternal<T: InternalProto> {} // expected-error {{generic struct cannot be declared public because its generic parameter uses an internal type}}

test/decl/protocol/req/recursion.swift

@@ -14,7 +14,7 @@ public struct S<A: P where A.T == S<A>> {}
 
 // rdar://problem/19840527
 class X<T where T == X> { // expected-error{{same-type requirement makes generic parameter 'T' non-generic}}
-    var type: T { return self.dynamicType } // expected-error{{use of undeclared type 'T'}}
+    var type: T { return self.dynamicType } // expected-error{{cannot convert return expression of type 'X<T>.Type' to return type 'T'}}
 }
 
 protocol Y {

validation-test/compiler_crashers/06252-swift-typechecker-conformstoprotocol.swift renamed to validation-test/compiler_crashers_fixed/06252-swift-typechecker-conformstoprotocol.swift

@@ -1,7 +1,7 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)
 // Test case found by fuzzing
 
-enum S{init(){enum S<T where S:T>:T
+enum S{init(){enum S<T where S:T>:T

validation-test/compiler_crashers/08893-std-function-func-swift-archetypebuilder-maptypeintocontext.swift renamed to validation-test/compiler_crashers_fixed/08893-std-function-func-swift-archetypebuilder-maptypeintocontext.swift

@@ -1,7 +1,7 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)
 // Test case found by fuzzing
 
-enum S<T where S:a>:T.j
+enum S<T where S:a>:T.j

validation-test/compiler_crashers/23060-swift-typechecker-validatedecl.swift renamed to validation-test/compiler_crashers_fixed/23060-swift-typechecker-validatedecl.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)

validation-test/compiler_crashers/24645-swift-diagnosticengine-flushactivediagnostic.swift renamed to validation-test/compiler_crashers_fixed/24645-swift-diagnosticengine-flushactivediagnostic.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)