[Sema] Avoid misleading diagnostics for incomplete enum computed properties

Author: LucianoPAlmeida

lib/Sema/TypeCheckStorage.cpp

@@ -3326,6 +3326,7 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
   bool hasModify = storage->getParsedAccessor(AccessorKind::Modify);
   bool hasMutableAddress = storage->getParsedAccessor(AccessorKind::MutableAddress);
 
+  auto *DC = storage->getDeclContext();
   // 'get', 'read', and a non-mutable addressor are all exclusive.
   ReadImplKind readImpl;
   if (storage->getParsedAccessor(AccessorKind::Get)) {
@@ -3354,10 +3355,10 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
       readImpl = ReadImplKind::Stored;
     }
 
-  // Extensions can't have stored properties. If there are braces, assume
-  // this is an incomplete computed property. This avoids an "extensions
-  // must not contain stored properties" error later on.
-  } else if (isa<ExtensionDecl>(storage->getDeclContext()) &&
+  // Extensions and enums can't have stored properties. If there are braces,
+  // assume this is an incomplete computed property. This avoids an
+  // "extensions|enums must not contain stored properties" error later on.
+  } else if ((isa<ExtensionDecl>(DC) || isa<EnumDecl>(DC)) &&
              storage->getBracesRange().isValid()) {
     readImpl = ReadImplKind::Get;
 

test/decl/var/properties.swift

@@ -1340,3 +1340,8 @@ class LazyPropInClass {
   lazy var foo: Int = { return 0 } // expected-error {{function produces expected type 'Int'; did you mean to call it with '()'?}}
   // expected-note@-1 {{Remove '=' to make 'foo' a computed property}}{{21-23=}}{{3-8=}}
 }
+
+// SR-15657
+enum SR15657 {
+  var foo: Int {} // expected-error{{computed property must have accessors specified}}
+}