Merge pull request swiftlang#19830 from gregomni/8813

[Sema] When resolving type declarations, if there is an error with a typealias,...

Author: gregomni

include/swift/AST/DiagnosticsSema.def

@@ -689,10 +689,11 @@ ERROR(use_nonmatching_operator,none,
       "%0 is not a %select{binary|prefix unary|postfix unary}1 operator",
       (DeclName, unsigned))
 ERROR(unsupported_recursion_in_associated_type_reference,none,
-      "unsupported recursion for reference to associated type %0 of type %1",
-      (DeclName, Type))
+      "unsupported recursion for reference to %select{associated type|type alias}0 %1 of type %2",
+      (bool, DeclName, Type))
 ERROR(broken_associated_type_witness,none,
-      "reference to invalid associated type %0 of type %1", (DeclName, Type))
+      "reference to invalid %select{associated type|type alias}0 %1 of type %2",
+      (bool, DeclName, Type))
 
 ERROR(unspaced_binary_operator_fixit,none,
       "missing whitespace between %0 and %1 operators",

lib/Sema/TypeCheckType.cpp

@@ -841,11 +841,15 @@ static void diagnoseUnboundGenericType(Type ty, SourceLoc loc) {
 static void maybeDiagnoseBadConformanceRef(DeclContext *dc,
                                            Type parentTy,
                                            SourceLoc loc,
-                                           AssociatedTypeDecl *assocType) {
+                                           TypeDecl *typeDecl) {
+  auto protocol = dyn_cast<ProtocolDecl>(typeDecl->getDeclContext());
+  if (!protocol)
+    return;
+
   // If we weren't given a conformance, go look it up.
   ProtocolConformance *conformance = nullptr;
   if (auto conformanceRef = TypeChecker::conformsToProtocol(
-          parentTy, assocType->getProtocol(), dc,
+          parentTy, protocol, dc,
           (ConformanceCheckFlags::InExpression |
            ConformanceCheckFlags::SuppressDependencyTracking |
            ConformanceCheckFlags::AllowUnavailableConditionalRequirements))) {
@@ -864,7 +868,7 @@ static void maybeDiagnoseBadConformanceRef(DeclContext *dc,
           ? diag::unsupported_recursion_in_associated_type_reference
           : diag::broken_associated_type_witness;
 
-  ctx.Diags.diagnose(loc, diagCode, assocType->getFullName(), parentTy);
+  ctx.Diags.diagnose(loc, diagCode, isa<TypeAliasDecl>(typeDecl), typeDecl->getFullName(), parentTy);
 }
 
 /// \brief Returns a valid type or ErrorType in case of an error.
@@ -910,10 +914,11 @@ static Type resolveTypeDecl(TypeDecl *typeDecl, SourceLoc loc,
     return ErrorType::get(ctx);
   }
 
-  if (type->hasError() && isa<AssociatedTypeDecl>(typeDecl)) {
+  if (type->hasError() && foundDC &&
+      (isa<AssociatedTypeDecl>(typeDecl) || isa<TypeAliasDecl>(typeDecl))) {
     maybeDiagnoseBadConformanceRef(fromDC,
                                    foundDC->getDeclaredInterfaceType(),
-                                   loc, cast<AssociatedTypeDecl>(typeDecl));
+                                   loc, typeDecl);
   }
 
   if (generic) {

test/decl/protocol/typealias_inference.swift

@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift
+
+// SR-8813
+// By itself in this file because this particular expected error is omitted if there have been any other diagnostics.
+protocol BaseProtocol {
+  associatedtype Value
+  typealias Closure = () -> Value
+
+  init(closure: Closure)
+}
+
+struct Base<Value>: BaseProtocol {
+  private let closure: Closure
+
+  init(closure: Closure) { //expected-error {{reference to invalid type alias 'Closure' of type 'Base<Value>'}}
+    self.closure = closure
+  }
+}

validation-test/compiler_crashers_2/0127-sr5546.swift renamed to validation-test/compiler_crashers_2_fixed/0127-sr5546.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -typecheck
+// RUN: not %target-swift-frontend %s -typecheck
 // REQUIRES: asserts
 
 public struct Foo<A, B, C> {}