Handle module selectors in macro lookups

include/swift/AST/DiagnosticsSema.def

@@ -8010,7 +8010,7 @@ ERROR(expected_macro_expansion_expr,PointsToFirstBadToken,
 ERROR(expected_macro_expansion_decls,PointsToFirstBadToken,
       "expected macro expansion to produce a declaration", ())
 ERROR(macro_undefined,PointsToFirstBadToken,
-      "no macro named %0", (DeclName))
+      "no macro named %0", (DeclNameRef))
 ERROR(external_macro_not_found,none,
       "external macro implementation type '%0.%1' could not be found for "
       "macro %2; %3", (StringRef, StringRef, DeclName, StringRef))

lib/Sema/CSGen.cpp

@@ -1440,7 +1440,7 @@ namespace {
         if (!protocol)
           return Type();
 
-        auto macroIdent = ctx.getIdentifier(kind);
+        auto macroIdent = DeclNameRef(ctx.getIdentifier(kind));
         auto macros = lookupMacros(Identifier(), macroIdent,
                                    FunctionRefInfo::unappliedBaseName(),
                                    MacroRole::Expression);
@@ -4111,12 +4111,12 @@ namespace {
 
     /// Lookup all macros with the given macro name.
     SmallVector<OverloadChoice, 1> lookupMacros(DeclName moduleName,
-                                                DeclName macroName,
+                                                DeclNameRef macroName,
                                                 FunctionRefInfo functionRefInfo,
                                                 MacroRoles roles) {
       SmallVector<OverloadChoice, 1> choices;
       auto results = namelookup::lookupMacros(CurDC, DeclNameRef(moduleName),
-                                              DeclNameRef(macroName), roles);
+                                              macroName, roles);
       for (const auto &result : results) {
         // Ignore invalid results. This matches the OverloadedDeclRefExpr
         // logic.
@@ -4143,7 +4143,7 @@ namespace {
 
       // Look up the macros with this name.
       auto moduleIdent = expr->getModuleName().getBaseName();
-      auto macroIdent = expr->getMacroName().getBaseName();
+      auto macroIdent = expr->getMacroName().withoutArgumentLabels(ctx);
       FunctionRefInfo functionRefInfo = FunctionRefInfo::singleBaseNameApply();
       auto macros = lookupMacros(moduleIdent, macroIdent, functionRefInfo,
                                  expr->getMacroRoles());

lib/Sema/TypeCheckType.cpp

@@ -1495,8 +1495,11 @@ static Type diagnoseUnknownType(const TypeResolution &resolution,
   if (parentType.isNull()) {
     // Tailored diagnostic for custom attributes.
     if (resolution.getOptions().is(TypeResolverContext::CustomAttr)) {
-      diags.diagnose(repr->getNameLoc(), diag::unknown_attr_name,
-                     repr->getNameRef().getBaseIdentifier().str());
+      SmallString<64> scratch;
+      llvm::raw_svector_ostream scratchOS(scratch);
+      repr->getNameRef().printPretty(scratchOS);
+
+      diags.diagnose(repr->getNameLoc(), diag::unknown_attr_name, scratch);
 
       return ErrorType::get(ctx);
     }
@@ -5171,9 +5174,13 @@ TypeResolver::resolveDeclRefTypeRepr(DeclRefTypeRepr *repr,
     if (!options.contains(TypeResolutionFlags::SilenceErrors)) {
       // Tailored diagnostic for custom attributes.
       if (options.is(TypeResolverContext::CustomAttr)) {
+        SmallString<64> scratch;
+        llvm::raw_svector_ostream scratchOS(scratch);
+        repr->getNameRef().printPretty(scratchOS);
+
         auto &ctx = resolution.getASTContext();
         ctx.Diags.diagnose(repr->getNameLoc(), diag::unknown_attr_name,
-                           repr->getNameRef().getBaseIdentifier().str());
+                           scratch);
 
         return ErrorType::get(ctx);
       }

test/NameLookup/Inputs/ModuleSelectorTestingKit.swiftinterface

@@ -40,3 +40,6 @@ public struct available {
 public struct MyBuilder {
   public static func buildBlock()
 }
+
+@freestanding(expression) public macro ExprMacro() -> String = #file
+@attached(peer) public macro PeerMacro() = #externalMacro(module: "Fnord", type: "PeerMacro")

test/NameLookup/module_selector.swift

@@ -11,7 +11,6 @@
 // * Cross-import overlays
 // * Key path dynamic member lookup
 // * Custom type attributes (and coverage of type attrs generally is sparse)
-// * Macros
 //
 // It also might not cover all combinations of name lookup paths and inputs.
 
@@ -58,6 +57,8 @@ extension A: @retroactive Swift::Equatable {
 
     _ = \ModuleSelectorTestingKit::A.magnitude
     _ = \A.ModuleSelectorTestingKit::magnitude
+
+    _ = #ModuleSelectorTestingKit::ExprMacro
   }
 
   // FIXME: Can we test @convention(witness_method:)?
@@ -124,8 +125,14 @@ extension B: @retroactive main::Equatable {
     // FIXME improve: expected-error@-1 {{'main::A' in scope}} -- different diagnostic wording for legacy parser vs. ASTGen
     _ = \A.main::magnitude
     // FIXME improve: expected-error@-1 {{value of type 'A' has no member 'main::magnitude'}}
+
+    _ = #main::ExprMacro
+    // expected-error@-1 {{no macro named 'main::ExprMacro'}}
   }
 
+  @main::PeerMacro func thingy() {}
+  // expected-error@-1 {{unknown attribute 'main::PeerMacro'}}
+
   // FIXME: Can we test @convention(witness_method:)?
 }
 
@@ -184,8 +191,13 @@ extension C: @retroactive ModuleSelectorTestingKit::Equatable {
 
     _ = \ModuleSelectorTestingKit::A.magnitude
     _ = \A.ModuleSelectorTestingKit::magnitude
+
+    _ = #ModuleSelectorTestingKit::ExprMacro
   }
 
+  @ModuleSelectorTestingKit::PeerMacro func thingy() {}
+  // expected-error@-1 {{external macro implementation type 'Fnord.PeerMacro' could not be found for macro 'PeerMacro()'; plugin for module 'Fnord' not found}}
+
   // FIXME: Can we test @convention(witness_method:)?
 }
 
@@ -244,8 +256,14 @@ extension D: @retroactive Swift::Equatable {
     // FIXME improve: expected-error@-1 {{'Swift::A' in scope}} -- different diagnostic wording for legacy parser vs. ASTGen
     _ = \A.Swift::magnitude
     // FIXME improve: expected-error@-1 {{value of type 'A' has no member 'Swift::magnitude'}}
+
+    _ = #Swift::ExprMacro
+    // expected-error@-1 {{no macro named 'Swift::ExprMacro'}}
   }
 
+  @Swift::PeerMacro func thingy() {}
+  // expected-error@-1 {{unknown attribute 'Swift::PeerMacro'}}
+
   // FIXME: Can we test @convention(witness_method:)?
 }
 
@@ -262,25 +280,25 @@ struct AvailableUser {
   @available(macOS 10.15, *) var use1: String { "foo" }
 
   @main::available() var use2
-  // FIXME improve: expected-error@-1 {{unknown attribute 'available'}}
+  // FIXME improve: expected-error@-1 {{unknown attribute 'main::available'}}
   // FIXME suppress: expected-error@-2 {{type annotation missing in pattern}}
 
   @ModuleSelectorTestingKit::available() var use4
   // no-error
 
   @Swift::available() var use5
-  // FIXME improve: expected-error@-1 {{unknown attribute 'available'}}
+  // FIXME improve: expected-error@-1 {{unknown attribute 'Swift::available'}}
   // FIXME suppress: expected-error@-2 {{type annotation missing in pattern}}
 }
 
 func builderUser2(@main::MyBuilder fn: () -> Void) {}
-// FIXME improve: expected-error@-1 {{unknown attribute 'MyBuilder'}}
+// FIXME improve: expected-error@-1 {{unknown attribute 'main::MyBuilder'}}
 
 func builderUser3(@ModuleSelectorTestingKit::MyBuilder fn: () -> Void) {}
 // no-error
 
 func builderUser4(@Swift::MyBuilder fn: () -> Void) {}
-// FIXME improve: expected-error@-1 {{unknown attribute 'MyBuilder'}}
+// FIXME improve: expected-error@-1 {{unknown attribute 'Swift::MyBuilder'}}
 
 // Error cases