[Macros] Return a ConcreteDeclRef from ResolveMacroRequest.

include/swift/AST/TypeCheckRequests.h

@@ -3181,16 +3181,16 @@ void simple_display(llvm::raw_ostream &out,
 /// Resolve a given custom attribute to an attached macro declaration.
 class ResolveMacroRequest
     : public SimpleRequest<ResolveMacroRequest,
-                           MacroDecl *(UnresolvedMacroReference,
-                                       DeclContext *),
+                           ConcreteDeclRef(UnresolvedMacroReference,
+                                           DeclContext *),
                            RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
 
 private:
   friend SimpleRequest;
 
-  MacroDecl *
+  ConcreteDeclRef
   evaluate(Evaluator &evaluator, UnresolvedMacroReference macroRef,
            DeclContext *dc) const;
 

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -341,7 +341,7 @@ SWIFT_REQUEST(TypeChecker, ResolveImplicitMemberRequest,
               evaluator::SideEffect(NominalTypeDecl *, ImplicitMemberAction),
               Uncached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ResolveMacroRequest,
-              MacroDecl *(CustomAttr *, DeclContext *),
+              ConcreteDeclRef(UnresolvedMacroReference, DeclContext *),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ResolveTypeEraserTypeRequest,
               Type(ProtocolDecl *, TypeEraserAttr *),

lib/AST/Decl.cpp

@@ -418,10 +418,12 @@ void Decl::forEachAttachedMacro(MacroRole role,
 }
 
 MacroDecl *Decl::getResolvedMacro(CustomAttr *customAttr) const {
-  return evaluateOrDefault(
+  auto declRef = evaluateOrDefault(
       getASTContext().evaluator,
       ResolveMacroRequest{customAttr, getDeclContext()},
-      nullptr);
+      ConcreteDeclRef());
+
+  return dyn_cast_or_null<MacroDecl>(declRef.getDecl());
 }
 
 unsigned Decl::getAttachedMacroDiscriminator(

lib/AST/NameLookup.cpp

@@ -1522,9 +1522,10 @@ populateLookupTableEntryFromMacroExpansions(ASTContext &ctx,
     auto *med = dyn_cast<MacroExpansionDecl>(member);
     if (!med)
       continue;
-    auto macro = evaluateOrDefault(
+    auto declRef = evaluateOrDefault(
         ctx.evaluator, ResolveMacroRequest{med, dc},
         nullptr);
+    auto *macro = dyn_cast_or_null<MacroDecl>(declRef.getDecl());
     if (!macro)
       continue;
     auto *attr = macro->getMacroRoleAttr(MacroRole::Declaration);

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -3779,22 +3779,9 @@ ExpandMacroExpansionDeclRequest::evaluate(Evaluator &evaluator,
     return {};
   }
   // Resolve macro candidates.
-  MacroDecl *macro;
-  if (auto *args = MED->getArgs()) {
-    macro = evaluateOrDefault(
-        ctx.evaluator, ResolveMacroRequest{MED, dc},
-        nullptr);
-  }
-  else {
-    if (foundMacros.size() > 1) {
-      MED->diagnose(diag::ambiguous_decl_ref, MED->getMacroName())
-          .highlight(MED->getMacroNameLoc().getSourceRange());
-      for (auto *candidate : foundMacros)
-        candidate->diagnose(diag::found_candidate);
-      return {};
-    }
-    macro = foundMacros.front();
-  }
+  auto macro = evaluateOrDefault(
+      ctx.evaluator, ResolveMacroRequest{MED, dc},
+      ConcreteDeclRef());
   if (!macro)
     return {};
   MED->setMacroRef(macro);

lib/Sema/TypeCheckMacros.cpp

@@ -1200,7 +1200,7 @@ swift::expandPeers(CustomAttr *attr, MacroDecl *macro, Decl *decl) {
   return macroSourceFile->getBufferID();
 }
 
-MacroDecl *
+ConcreteDeclRef
 ResolveMacroRequest::evaluate(Evaluator &evaluator,
                               UnresolvedMacroReference macroRef,
                               DeclContext *dc) const {
@@ -1209,7 +1209,7 @@ ResolveMacroRequest::evaluate(Evaluator &evaluator,
   auto foundMacros = TypeChecker::lookupMacros(
       dc, macroRef.getMacroName(), SourceLoc(), roles);
   if (foundMacros.empty())
-    return nullptr;
+    return ConcreteDeclRef();
 
   // If we already have a MacroExpansionExpr, use that. Otherwise,
   // create one.
@@ -1228,13 +1228,9 @@ ResolveMacroRequest::evaluate(Evaluator &evaluator,
   Expr *result = macroExpansion;
   TypeChecker::typeCheckExpression(result, dc);
 
-  auto macroDeclRef = macroExpansion->getMacroRef();
-  if (auto *macroDecl = dyn_cast_or_null<MacroDecl>(macroDeclRef.getDecl()))
-    return macroDecl;
-
   // If we couldn't resolve a macro decl, the attribute is invalid.
-  if (auto *attr = macroRef.getAttr())
-    attr->setInvalid();
+  if (!macroExpansion->getMacroRef() && macroRef.getAttr())
+    macroRef.getAttr()->setInvalid();
 
-  return nullptr;
+  return macroExpansion->getMacroRef();
 }