Merge pull request swiftlang#14423 from xedin/rdar-36989792-5.0

[5.0] [DeclChecker] Don't try to derive conformances for invalid enums

Author: xedin

lib/Sema/TypeCheckDecl.cpp

@@ -4518,20 +4518,24 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       {
         // Check for duplicate enum members.
         llvm::DenseMap<Identifier, EnumElementDecl *> Elements;
+        bool hasErrors = false;
         for (auto *EED : ED->getAllElements()) {
           auto Res = Elements.insert({ EED->getName(), EED });
           if (!Res.second) {
-            EED->setInterfaceType(ErrorType::get(TC.Context));
             EED->setInvalid();
-            if (auto *RawValueExpr = EED->getRawValueExpr())
-              RawValueExpr->setType(ErrorType::get(TC.Context));
 
             auto PreviousEED = Res.first->second;
             TC.diagnose(EED->getLoc(), diag::duplicate_enum_element);
             TC.diagnose(PreviousEED->getLoc(),
                         diag::previous_decldef, true, EED->getName());
+            hasErrors = true;
           }
         }
+
+        // If one of the cases is invalid, let's mark
+        // whole enum as invalid as well.
+        if (hasErrors)
+          ED->setInvalid();
       }
     }
 

lib/Sema/TypeCheckProtocol.cpp

@@ -4655,6 +4655,8 @@ ValueDecl *TypeChecker::deriveProtocolRequirement(DeclContext *DC,
     return nullptr;
 
   auto Decl = DC->getInnermostDeclarationDeclContext();
+  if (Decl->isInvalid())
+    return nullptr;
 
   switch (*knownKind) {
   case KnownProtocolKind::RawRepresentable:

validation-test/compiler_crashers_2_fixed/0141-rdar36989792.swift

@@ -0,0 +1,6 @@
+// RUN: not %target-swift-frontend %s -typecheck
+
+enum E : Equatable {
+    case c(Int)
+    case c(String)
+}