Sema: Fix type member lookup if generic signature validation fails

When validateGenericFuncSignature() returns true, finalizeGenericParamList()
is never called. Name lookup, via PartialGenericTypeToArchetypeResolver would
return a dependent member type of the generic type parameter type, not an
archetype as expected in this case. This would later on lead to a crash in
ReplaceDependentTypes if the function body contained a reference to such a
member type.

Fix this by marking the GenericTypeParamDecls as invalid in this case, and
returning an ErrorType from PartialGenericTypeToArchetypeResolver if given
an invalid GenericTypeParamDecl.

While we're at it, there was an unused isInvalid local variable in
TypeCheckDecl::visitFuncDecl(). It was written to but never read. Replace
the writes with calls to setInvalid().

Fixes <rdar://problem/19620340>.

Swift SVN r30632

Author: slavapestov

lib/Sema/TypeCheckDecl.cpp

@@ -1003,6 +1003,32 @@ void TypeChecker::revertGenericParamList(GenericParamList *genericParams) {
   }
 }
 
+static void markInvalidGenericSignature(AbstractFunctionDecl *AFD,
+                                        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.
+  addContextParamsAndRequirements(builder, AFD->getDeclContext());
+  
+  // If there aren't any generic parameters at this level, we're done.
+  if (!genericParams)
+    return;
+  
+  // Visit each of the generic parameters.
+  for (auto param : *genericParams)
+    builder.addGenericParameter(param);
+  
+  // Wire up the archetypes.
+  for (auto GP : *genericParams)
+    GP->setArchetype(builder.getArchetype(GP));
+
+  genericParams->setAllArchetypes(
+      TC.Context.AllocateCopy(builder.getAllArchetypes()));
+}
+
+
 /// Finalize the given generic parameter list, assigning archetypes to
 /// the generic parameters.
 static void finalizeGenericParamList(ArchetypeBuilder &builder,
@@ -4104,11 +4130,9 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     else if (FD->getAttrs().hasAttribute<NonMutatingAttr>())
       FD->setMutating(false);
 
-    bool isInvalid = false;
-
     // Check whether the return type is dynamic 'Self'.
     if (checkDynamicSelfReturn(FD))
-      isInvalid = true;
+      FD->setInvalid();
 
     // Observing accessors (and their generated regular accessors) may have
     // the type of the var inferred.
@@ -4138,9 +4162,9 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     if (auto gp = FD->getGenericParams()) {
       gp->setOuterParameters(outerGenericParams);
 
-      if (TC.validateGenericFuncSignature(FD))
-        isInvalid = true;
-      else {
+      if (TC.validateGenericFuncSignature(FD)) {
+        markInvalidGenericSignature(FD, TC);
+      } else {
         // Create a fresh archetype builder.
         ArchetypeBuilder builder =
           TC.createArchetypeBuilder(FD->getModuleContext());
@@ -4156,15 +4180,17 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           builder.inferRequirements(FD->getBodyResultTypeLoc(), gp);
         }
 
-        // Revert all of the types within the signature of the function.
+        // Revert the types within the signature so it can be type-checked with
+        // archetypes below.
         TC.revertGenericFuncSignature(FD);
 
+        // Assign archetypes.
         finalizeGenericParamList(builder, FD->getGenericParams(), FD, TC);
       }
     } else if (outerGenericParams) {
-      if (TC.validateGenericFuncSignature(FD))
-        isInvalid = true;
-      else if (!FD->hasType()) {
+      if (TC.validateGenericFuncSignature(FD)) {
+        markInvalidGenericSignature(FD, TC);
+      } else if (!FD->hasType()) {
         // Revert all of the types within the signature of the function.
         TC.revertGenericFuncSignature(FD);
       } else {
@@ -5511,8 +5537,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       gp->setOuterParameters(outerGenericParams);
 
       if (TC.validateGenericFuncSignature(CD)) {
-        CD->overwriteType(ErrorType::get(TC.Context));
-        CD->setInvalid();
+        markInvalidGenericSignature(CD, TC);
       } else {
         ArchetypeBuilder builder =
           TC.createArchetypeBuilder(CD->getModuleContext());
@@ -5527,7 +5552,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         // Infer requirements from the parameters of the constructor.
         builder.inferRequirements(CD->getBodyParamPatterns()[1], gp);
 
-        // Revert the constructor signature so it can be type-checked with
+        // Revert the types within the signature so it can be type-checked with
         // archetypes below.
         TC.revertGenericFuncSignature(CD);
 
@@ -5536,7 +5561,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       }
     } else if (outerGenericParams) {
       if (TC.validateGenericFuncSignature(CD)) {
-        CD->overwriteType(ErrorType::get(TC.Context));
         CD->setInvalid();
       } else {
         // Revert all of the types within the signature of the constructor.
@@ -5975,16 +5999,18 @@ void TypeChecker::validateDecl(ValueDecl *D, bool resolveTypeParams) {
     if (proto->hasType())
       return;
     proto->computeType();
+    
+    auto gp = proto->getGenericParams();
 
     // Validate the generic type parameters.
     validateGenericTypeSignature(proto);
 
-    revertGenericParamList(proto->getGenericParams());
+    revertGenericParamList(gp);
 
     ArchetypeBuilder builder =
       createArchetypeBuilder(proto->getModuleContext());
-    checkGenericParamList(builder, proto->getGenericParams(), *this);
-    finalizeGenericParamList(builder, proto->getGenericParams(), proto, *this);
+    checkGenericParamList(builder, gp, *this);
+    finalizeGenericParamList(builder, gp, proto, *this);
 
     checkInheritanceClause(D);
     validateAttributes(*this, D);

lib/Sema/TypeCheckGeneric.cpp

@@ -90,6 +90,7 @@ Type PartialGenericTypeToArchetypeResolver::resolveGenericTypeParamType(
   if (!gpDecl)
     return Type(gp);
 
+
   auto archetype = gpDecl->getArchetype();
   if (!archetype)
     return Type(gp);

test/Generics/associated_type_typo.swift

@@ -39,3 +39,17 @@ func typoAssoc4<T : P2 where T.Assocp2.assoc : P3>(_: T) { }
 // CHECK-NEXT:   T[.P2].AssocP2[.P1].Assoc : P3 [explicit
 // CHECK-NEXT:   T[.P2].AssocP2.assoc == T[.P2].AssocP2[.P1].Assoc [protocol
 // CHECK-NEXT: Generic signature
+
+
+// <rdar://problem/19620340>
+
+func typoFunc1<T : P1>(x: TypoType) { // expected-error{{use of undeclared type 'TypoType'}}
+  let _: T.Assoc -> () = { let _ = $0 }
+}
+
+func typoFunc2<T : P1>(x: TypoType, y: T) { // expected-error{{use of undeclared type 'TypoType'}}
+  let _: T.Assoc -> () = { let _ = $0 }
+}
+
+func typoFunc3<T : P1>(x: TypoType, y: T.Assoc -> ()) { // expected-error{{use of undeclared type 'TypoType'}}
+}

validation-test/compiler_crashers/0357-swift-type-transform.swift renamed to validation-test/compiler_crashers_fixed/0357-swift-type-transform.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/0416-swift-typechecker-conformstoprotocol.swift renamed to validation-test/compiler_crashers_fixed/0416-swift-typechecker-conformstoprotocol.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/0535-swift-type-transform.swift renamed to validation-test/compiler_crashers_fixed/0535-swift-type-transform.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/0756-llvm-ondiskchainedhashtable-swift-modulefile-decltableinfo-find.swift renamed to validation-test/compiler_crashers_fixed/0756-llvm-ondiskchainedhashtable-swift-modulefile-decltableinfo-find.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/0781-swift-constraints-constraintsystem-diagnosefailurefromconstraints.swift renamed to validation-test/compiler_crashers_fixed/0781-swift-constraints-constraintsystem-diagnosefailurefromconstraints.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/1366-swift-constraints-constraintsystem-simplifyconstraint.swift renamed to validation-test/compiler_crashers_fixed/1366-swift-constraints-constraintsystem-simplifyconstraint.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/2108-swift-type-transform.swift renamed to validation-test/compiler_crashers_fixed/2108-swift-type-transform.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)