AST: Implement extractNearestSourceLoc() for ProtocolConformance

Author: slavapestov

include/swift/AST/ProtocolConformance.h

@@ -1022,6 +1022,7 @@ inline bool ProtocolConformance::hasWitness(ValueDecl *requirement) const {
   return getRootConformance()->hasWitness(requirement);
 }
 
+SourceLoc extractNearestSourceLoc(const ProtocolConformance *conf);
 void simple_display(llvm::raw_ostream &out, const ProtocolConformance *conf);
 
 } // end namespace swift

lib/AST/ProtocolConformance.cpp

@@ -1531,6 +1531,10 @@ void swift::simple_display(llvm::raw_ostream &out,
   conf->printName(out);
 }
 
+SourceLoc swift::extractNearestSourceLoc(const ProtocolConformance *conformance) {
+  return extractNearestSourceLoc(conformance->getDeclContext());
+}
+
 void swift::simple_display(llvm::raw_ostream &out, ProtocolConformanceRef conformanceRef) {
   if (conformanceRef.isAbstract()) {
     simple_display(out, conformanceRef.getAbstract());
@@ -1543,7 +1547,7 @@ SourceLoc swift::extractNearestSourceLoc(const ProtocolConformanceRef conformanc
   if (conformanceRef.isAbstract()) {
     return extractNearestSourceLoc(conformanceRef.getAbstract());
   } else if (conformanceRef.isConcrete()) {
-    return extractNearestSourceLoc(conformanceRef.getConcrete()->getProtocol());
+    return extractNearestSourceLoc(conformanceRef.getConcrete());
   }
   return SourceLoc();
 }

test/decl/circularity.swift

@@ -61,7 +61,6 @@ extension SIMD3 where SIMD3.Scalar == Float {
 protocol P {
     associatedtype A
     // expected-note@-1 {{protocol requires nested type 'A'; do you want to add it?}}
-    // expected-note@-2 {{through reference here}}
     func run(a: A)
 }
 
@@ -70,6 +69,7 @@ class C1 {
 }
 
 class C2: C1, P {
+    // expected-note@-1 {{through reference here}}
     override func run(a: A) {}
     // expected-error@-1 {{circular reference}}
     // expected-note@-2 {{while resolving type 'A'}}
@@ -90,15 +90,15 @@ class C3: G1<A>, P {
 
 // Another case that triggers circular override checking.
 protocol P1 {
-  associatedtype X = Int // expected-note {{through reference here}}
+  associatedtype X = Int
   init(x: X)
 }
 
 class C4 {
   required init(x: Int) {}
 }
 
-class D4 : C4, P1 { // expected-note 2 {{through reference here}}
+class D4 : C4, P1 { // expected-note 3 {{through reference here}}
   required init(x: X) { // expected-error {{circular reference}}
     // expected-note@-1 {{while resolving type 'X'}}
     // expected-note@-2 2{{through reference here}}