Small cleanup to aid debugging and some regression tests

lib/AST/Decl.cpp

@@ -1256,9 +1256,11 @@ AccessLevel ExtensionDecl::getMaxAccessLevel() const {
 
 Type ExtensionDecl::getExtendedType() const {
   ASTContext &ctx = getASTContext();
-  return evaluateOrDefault(ctx.evaluator,
-    ExtendedTypeRequest{const_cast<ExtensionDecl *>(this)},
-    ErrorType::get(ctx));
+  if (auto type = evaluateOrDefault(ctx.evaluator,
+          ExtendedTypeRequest{const_cast<ExtensionDecl *>(this)},
+          Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 /// Clone the given generic parameters in the given list. We don't need any
@@ -2881,19 +2883,21 @@ bool ValueDecl::isRecursiveValidation() const {
 }
 
 Type ValueDecl::getInterfaceType() const {
+  auto &ctx = getASTContext();
+
   // Our clients that don't register the lazy resolver are relying on the
   // fact that they can't pull an interface type out to avoid doing work.
   // This is a necessary evil until we can wean them off.
-  if (!getASTContext().getLazyResolver()) {
+  if (!ctx.getLazyResolver()) {
     return TypeAndAccess.getPointer();
   }
 
-  if (auto Ty =
-          evaluateOrDefault(getASTContext().evaluator,
+  if (auto type =
+          evaluateOrDefault(ctx.evaluator,
                             InterfaceTypeRequest{const_cast<ValueDecl *>(this)},
-                            ErrorType::get(getASTContext())))
-    return Ty;
-  return ErrorType::get(getASTContext());
+                            Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 void ValueDecl::setInterfaceType(Type type) {
@@ -3695,9 +3699,11 @@ SourceRange TypeAliasDecl::getSourceRange() const {
 
 Type TypeAliasDecl::getUnderlyingType() const {
   auto &ctx = getASTContext();
-  return evaluateOrDefault(ctx.evaluator,
+  if (auto type = evaluateOrDefault(ctx.evaluator,
            UnderlyingTypeRequest{const_cast<TypeAliasDecl *>(this)},
-           ErrorType::get(ctx));
+           Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 void TypeAliasDecl::setUnderlyingType(Type underlying) {
@@ -3728,10 +3734,12 @@ UnboundGenericType *TypeAliasDecl::getUnboundGenericType() const {
 
 Type TypeAliasDecl::getStructuralType() const {
   auto &ctx = getASTContext();
-  return evaluateOrDefault(
+  if (auto type = evaluateOrDefault(
       ctx.evaluator,
       StructuralTypeRequest{const_cast<TypeAliasDecl *>(this)},
-      ErrorType::get(ctx));
+      Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 Type AbstractTypeParamDecl::getSuperclass() const {
@@ -6313,9 +6321,11 @@ void SubscriptDecl::setIndices(ParameterList *p) {
 Type SubscriptDecl::getElementInterfaceType() const {
   auto &ctx = getASTContext();
   auto mutableThis = const_cast<SubscriptDecl *>(this);
-  return evaluateOrDefault(ctx.evaluator,
+  if (auto type = evaluateOrDefault(ctx.evaluator,
                            ResultTypeRequest{mutableThis},
-                           ErrorType::get(ctx));
+                           Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 ObjCSubscriptKind SubscriptDecl::getObjCSubscriptKind() const {
@@ -6943,9 +6953,11 @@ StaticSpellingKind FuncDecl::getCorrectStaticSpelling() const {
 Type FuncDecl::getResultInterfaceType() const {
   auto &ctx = getASTContext();
   auto mutableThis = const_cast<FuncDecl *>(this);
-  return evaluateOrDefault(ctx.evaluator,
+  if (auto type = evaluateOrDefault(ctx.evaluator,
                            ResultTypeRequest{mutableThis},
-                           ErrorType::get(ctx));
+                           Type()))
+    return type;
+  return ErrorType::get(ctx);
 }
 
 bool FuncDecl::isUnaryOperator() const {

test/Parse/confusables.swift

@@ -19,7 +19,5 @@ if (true ꝸꝸꝸ false) {} // expected-note {{identifier 'ꝸꝸꝸ' contains
 // expected-error @+2 {{expected ',' separator}}
 // expected-error @+1 {{type '(Int, Int)' cannot conform to 'BinaryInteger'; only struct/enum/class types can conform to protocols}}
 if (5 ‒ 5) == 0 {} // expected-note {{unicode character '‒' looks similar to '-'; did you mean to use '-'?}} {{7-10=-}}
-// expected-note @-1 {{required by referencing operator function '==' on 'BinaryInteger' where}}
+// expected-note @-1 {{required by referencing operator function '==' on 'BinaryInteger' where 'Self' = '(Int, Int)'}}
 
-// FIXME: rdar://56002633
-// Above note should read "required by referencing operator function '==' on 'BinaryInteger' where 'Self' = '(Int, Int)'"

validation-test/compiler_crashers_2_fixed/rdar56700017.swift

@@ -0,0 +1,17 @@
+// RUN: %target-swift-frontend -typecheck %s
+
+extension Sequence {
+    func sorted<T: Comparable, K: KeyPath<Element, T>>(by keyPath: K) -> Array<Element> {
+        self.sorted { $0[keyPath:keyPath] < $1[keyPath:keyPath] }
+    }
+}
+
+struct Foo {
+    let a: Int
+}
+
+func main() {
+    print([Foo(a: 2), Foo(a:1), Foo(a:4), Foo(a:3)].sorted(by: \Foo.a))
+}
+
+main()

validation-test/compiler_crashers_2_fixed/sr8968.swift

@@ -0,0 +1,46 @@
+// RUN: %target-swift-frontend -typecheck %s
+
+class OFMAttachment : NativeInserting {
+    typealias SnapshotType = Message.Attachment
+}
+
+protocol Snapshotting {
+    associatedtype NativeType: NativeInserting where NativeType.SnapshotType == Self
+    associatedtype RecordType: SnapshotRecord where RecordType.SnapshotType == Self
+    associatedtype ChangeType: SnapshotChange where ChangeType.SnapshotType == Self
+
+    static var baseMessageName: String { get }
+}
+
+protocol NativeInserting {
+    associatedtype SnapshotType : Snapshotting where SnapshotType.NativeType == Self
+}
+
+protocol SnapshotRecord {
+    associatedtype SnapshotType : Snapshotting where SnapshotType.RecordType == Self
+
+}
+
+protocol SnapshotChange {
+    associatedtype SnapshotType : Snapshotting where SnapshotType.ChangeType == Self
+}
+
+struct Message {
+    enum Attachment : Snapshotting {
+
+        static var baseMessageName: String = "attachment"
+
+        typealias NativeType = OFMAttachment
+        typealias RecordType = Record
+        typealias ChangeType = Change
+        struct Record : SnapshotRecord {
+            typealias SnapshotType = Message.Attachment
+        }
+
+        struct Change : SnapshotChange {
+            typealias SnapshotType = Message.Attachment
+        }
+
+    }
+}
+