Error when one associated type is constrained to another.

lib/Sema/ITCDecl.cpp

@@ -108,14 +108,24 @@ void IterativeTypeChecker::processResolveInheritedClauseEntry(
 
   // Validate the type of this inherited clause entry.
   // FIXME: Recursion into existing type checker.
-  GenericTypeToArchetypeResolver resolver(dc);
-  if (TC.validateType(*inherited, dc, options, &resolver,
+  Optional<ProtocolRequirementTypeResolver> protoResolver;
+  Optional<GenericTypeToArchetypeResolver> archetypeResolver;
+  GenericTypeResolver *resolver;
+  if (auto *proto = dyn_cast<ProtocolDecl>(dc)) {
+    protoResolver.emplace(proto);
+    resolver = protoResolver.getPointer();
+  } else {
+    archetypeResolver.emplace(dc);
+    resolver = archetypeResolver.getPointer();
+  }
+
+  if (TC.validateType(*inherited, dc, options, resolver,
                       &unsatisfiedDependency)) {
     inherited->setInvalidType(getASTContext());
   }
 
   auto type = inherited->getType();
-  if (!type.isNull())
+  if (!type.isNull() && !isa<ProtocolDecl>(dc))
     inherited->setType(dc->mapTypeOutOfContext(type));
 }
 

test/Sema/circular_decl_checking.swift

@@ -43,9 +43,10 @@ func TopLevelGenericFunc2<T : TopLevelGenericFunc2>(x: T) -> T { return x} // ex
 var TopLevelVar: TopLevelVar? { return nil } // expected-error 2 {{use of undeclared type 'TopLevelVar'}}
 
 
-protocol AProtocol {
-  // FIXME: Should produce an error here, but it's currently causing problems.
-  associatedtype e : e
+// FIXME: The first error is redundant, isn't correct in what it states, and
+// also should be emitted on the inheritance clause.
+protocol AProtocol { // expected-error {{first type 'Self.e' in conformance requirement does not refer to a generic parameter or associated type}}
+  associatedtype e : e // expected-error {{inheritance from non-protocol, non-class type 'Self.e'}}
 }
 
 

test/decl/nested/protocol.swift

@@ -72,5 +72,6 @@ class OuterClass {
 
 class OtherGenericClass<T> {
   protocol InnerProtocol : OtherGenericClass { }
-  // expected-error@-1{{protocol 'InnerProtocol' cannot be nested inside another declaration}}
+  // expected-error@-1{{non-class type 'InnerProtocol' cannot inherit from class 'OtherGenericClass<T>'}}
+  // expected-error@-2{{protocol 'InnerProtocol' cannot be nested inside another declaration}}
 }

test/decl/protocol/req/unsatisfiable.swift

@@ -30,3 +30,21 @@ protocol P3 {
   func f<T: P3>(_: T) where T.A == Self.A, T.A: C // expected-error{{instance method requirement 'f' cannot add constraint 'Self.A: C' on 'Self'}}
   func g<T: P3>(_: T) where T.A: C, T.A == Self.A  // expected-error{{instance method requirement 'g' cannot add constraint 'Self.A: C' on 'Self'}}
 }
+
+protocol Base {
+  associatedtype Assoc
+}
+
+// FIXME: The first error is redundant, isn't correct in what it states, and
+// also should be emitted on the inheritance clause.
+// FIXME: This used to /not/ error in Swift 3. It didn't impose any statically-
+// enforced requirements, but the compiler crashed if you used anything but the
+// same type.
+protocol Sub1: Base { // expected-error {{first type 'Self.Assoc' in conformance requirement does not refer to a generic parameter or associated type}}
+  associatedtype SubAssoc: Assoc // expected-error {{inheritance from non-protocol, non-class type 'Self.Assoc'}}
+}
+// FIXME: This error is incorrect in what it states and should be emitted on
+// the where-clause.
+protocol Sub2: Base { // expected-error {{first type 'Self.Assoc' in conformance requirement does not refer to a generic parameter or associated type}}
+  associatedtype SubAssoc where SubAssoc: Assoc
+}

validation-test/compiler_crashers/28693-swift-genericenvironment-queryinterfacetypesubstitutions-operator-swift-substitu.swift → validation-test/compiler_crashers_fixed/28693-swift-genericenvironment-queryinterfacetypesubstitutions-operator-swift-substitu.swift

@@ -5,5 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol b:Self