[Diagnostics] Display correct debug note for compound references typo suggestions

include/swift/AST/DiagnosticsSema.def

@@ -596,7 +596,7 @@ ERROR(use_undeclared_type,none,
 ERROR(use_undeclared_type_did_you_mean,none,
  "use of undeclared type %0; did you mean to use '%1'?", (Identifier, StringRef))
 NOTE(note_typo_candidate,none,
- "did you mean '%0'?", (StringRef))
+ "did you mean %0?", (DeclName))
 NOTE(note_typo_candidate_implicit_member,none,
  "did you mean the implicitly-synthesized %1 '%0'?", (StringRef, StringRef))
 NOTE(note_remapped_type,none,

lib/Sema/TypeCheckConstraints.cpp

@@ -452,7 +452,7 @@ resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE, DeclContext *DC) {
 
  // Note all the correction candidates.
  for (auto &result : Lookup) {
- noteTypoCorrection(Name, nameLoc, result);
+ noteTypoCorrection(Name, nameLoc, result, UDRE->getFunctionRefKind());
  }
 
  // TODO: consider recovering from here. We may want some way to suppress

lib/Sema/TypeCheckNameLookup.cpp

@@ -555,13 +555,21 @@ void TypeChecker::performTypoCorrection(DeclContext *DC, DeclRefKind refKind,
 }
 
 static InFlightDiagnostic
-diagnoseTypoCorrection(TypeChecker &tc, DeclNameLoc loc, ValueDecl *decl) {
+diagnoseTypoCorrection(TypeChecker &tc,
+ DeclNameLoc loc, 
+ ValueDecl *decl, 
+ FunctionRefKind refKind) {
+
+ auto name = refKind == FunctionRefKind::Compound ? decl->getFullName() :
+ decl->getName();
+
  if (auto var = dyn_cast<VarDecl>(decl)) {
  // Suggest 'self' at the use point instead of pointing at the start
  // of the function.
+
  if (var->isSelfParameter())
  return tc.diagnose(loc.getBaseNameLoc(), diag::note_typo_candidate,
- decl->getName().str());
+ name);
  }
 
  if (!decl->getLoc().isValid() && decl->getDeclContext()->isTypeContext()) {
@@ -579,13 +587,15 @@ diagnoseTypoCorrection(TypeChecker &tc, DeclNameLoc loc, ValueDecl *decl) {
  }
  }
 
- return tc.diagnose(decl, diag::note_typo_candidate, decl->getName().str());
+ return tc.diagnose(decl, diag::note_typo_candidate, name);
 }
 
-void TypeChecker::noteTypoCorrection(DeclName writtenName, DeclNameLoc loc,
- const LookupResult::Result &suggestion) {
+void TypeChecker::noteTypoCorrection(DeclName writtenName,
+ DeclNameLoc loc,
+ const LookupResult::Result &suggestion,
+ FunctionRefKind refKind) {
  auto decl = suggestion.Decl;
- auto &&diagnostic = diagnoseTypoCorrection(*this, loc, decl);
+ auto &&diagnostic = diagnoseTypoCorrection(*this, loc, decl, refKind);
 
  DeclName declName = decl->getFullName();
 

lib/Sema/TypeChecker.h

@@ -2083,7 +2083,8 @@ class TypeChecker final : public LazyResolver {
  unsigned maxResults = 4);
 
  void noteTypoCorrection(DeclName name, DeclNameLoc nameLoc,
- const LookupResult::Result &suggestion);
+ const LookupResult::Result &suggestion,
+ FunctionRefKind refKind = FunctionRefKind::Unapplied);
 
  /// Check if the given decl has a @_semantics attribute that gives it
  /// special case type-checking behavior.

test/Sema/compound_references.swift

@@ -0,0 +1,4 @@
+// RUN: %target-typecheck-verify-swift
+
+func foo(x: Int) {} // expected-note * {{did you mean 'foo(x:)'?}}
+let f = foo(_:) // expected-error {{use of unresolved identifier 'foo'}}