Merge pull request swiftlang#63533 from DougGregor/minor-macro-fixes

Author: DougGregor

include/swift/AST/DeclContext.h

@@ -519,6 +519,12 @@ class alignas(1 << DeclContextAlignInBits) DeclContext
   LLVM_READONLY
   SourceFile *getParentSourceFile() const;
 
+  /// Returns the "outermost" source file that contains this context,
+  /// looking through any source files for generated code, such as
+  /// macro expansions.
+  LLVM_READONLY
+  SourceFile *getOutermostParentSourceFile() const;
+
   /// Determine whether this declaration context is generic, meaning that it or
   /// any of its parents have generic parameters.
   bool isGenericContext() const;

lib/AST/DeclContext.cpp

@@ -323,6 +323,18 @@ SourceFile *DeclContext::getParentSourceFile() const {
   return fallbackSF;
 }
 
+SourceFile *DeclContext::getOutermostParentSourceFile() const {
+  auto sf = getParentSourceFile();
+  if (!sf)
+    return nullptr;
+
+  // Find the originating source file.
+  while (auto enclosingSF = sf->getEnclosingSourceFile())
+    sf = enclosingSF;
+
+  return sf;
+}
+
 DeclContext *DeclContext::getModuleScopeContext() const {
   auto DC = const_cast<DeclContext*>(this);
 

lib/IRGen/IRGenModule.cpp

@@ -1919,10 +1919,11 @@ IRGenModule *IRGenerator::getGenModule(DeclContext *ctxt) {
   if (GenModules.size() == 1 || !ctxt) {
     return getPrimaryIGM();
   }
-  SourceFile *SF = ctxt->getParentSourceFile();
+  SourceFile *SF = ctxt->getOutermostParentSourceFile();
   if (!SF) {
     return getPrimaryIGM();
   }
+
   IRGenModule *IGM = GenModules[SF];
   assert(IGM);
   return IGM;

lib/Parse/ParseDecl.cpp

@@ -9502,9 +9502,8 @@ ParserResult<MacroDecl> Parser::parseDeclMacro(DeclAttributes &attributes) {
   } else {
     // Parameter list.
     SmallVector<Identifier, 2> namePieces;
-    DefaultArgumentInfo defaultArgs;
     auto parameterResult = parseSingleParameterClause(
-        ParameterContextKind::Macro, &namePieces, &defaultArgs);
+        ParameterContextKind::Macro, &namePieces, nullptr);
     status |= parameterResult;
     parameterList = parameterResult.getPtrOrNull();
 

test/Macros/macros_diagnostics.swift

@@ -134,3 +134,8 @@ func testExternalMacroOutOfPlace() {
   let _: Int = #externalMacro(module: "A", type: "B")
   // expected-error@-1{{macro 'externalMacro' can only be used to define another macro}}
 }
+
+@freestanding(expression)
+public macro macroWithDefaults(_: Int = 17) = #externalMacro(module: "A", type: "B")
+// expected-error@-1{{default arguments are not allowed in macros}}
+// expected-warning@-2{{external macro implementation type 'A.B' could not be found for macro 'macroWithDefaults'}}