AST: Stricter DeclContext::getParentForLookup()

Author: slavapestov

lib/AST/DeclContext.cpp

@@ -445,6 +445,12 @@ DeclContext *DeclContext::getParentForLookup() const {
     // outer types.
     return getModuleScopeContext();
   }
+  if (isa<NominalTypeDecl>(this)) {
+    // If we are inside a nominal type that is inside a protocol,
+    // skip the protocol.
+    if (isa<ProtocolDecl>(getParent()))
+      return getModuleScopeContext();
+  }
   return getParent();
 }
 

test/decl/nested/protocol.swift

@@ -40,9 +40,11 @@ protocol Racoon {
   associatedtype Stripes
   class Claw<T> { // expected-error{{type 'Claw' cannot be nested in protocol 'Racoon'}}
     func mangle(_ s: Stripes) {}
+    // expected-error@-1 {{use of undeclared type 'Stripes'}}
   }
   struct Fang<T> { // expected-error{{type 'Fang' cannot be nested in protocol 'Racoon'}}
     func gnaw(_ s: Stripes) {}
+    // expected-error@-1 {{use of undeclared type 'Stripes'}}
   }
   enum Fur { // expected-error{{type 'Fur' cannot be nested in protocol 'Racoon'}}
     case Stripes

validation-test/compiler_crashers/28753-conforms-equivclass-conformsto-end.swift renamed to validation-test/compiler_crashers_fixed/28753-conforms-equivclass-conformsto-end.swift

@@ -6,5 +6,5 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol A:A{{}class a{let ca{a{

validation-test/compiler_crashers/28765-inprotocol-isrequirementsignaturecomputed-missing-signature.swift renamed to validation-test/compiler_crashers_fixed/28765-inprotocol-isrequirementsignaturecomputed-missing-signature.swift

@@ -6,5 +6,5 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol P{{}class a:A{}protocol A:P.a{typealias a{}func a:a

validation-test/compiler_crashers/28773-unreachable-executed-at-swift-lib-sema-cssimplify-cpp-4808.swift renamed to validation-test/compiler_crashers_fixed/28773-unreachable-executed-at-swift-lib-sema-cssimplify-cpp-4808.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
 @objc protocol P{{}typealias a{}class a{let c=a{