[Macros] Diagnose default literal type overrides in macro expansions.

Author: hborla

include/swift/AST/DiagnosticsSema.def

@@ -6913,8 +6913,11 @@ ERROR(invalid_decl_in_macro_expansion,none,
       "macro expansion cannot introduce %0",
       (DescriptiveDeclKind))
 ERROR(invalid_main_type_in_macro_expansion,none,
-      "macro expansion cannot introduce '@main' type'",
+      "macro expansion cannot introduce '@main' type",
       ())
+ERROR(literal_type_in_macro_expansion,none,
+      "macro expansion cannot introduce default literal type %0",
+      (Identifier))
 ERROR(invalid_macro_introduced_name,none,
       "declaration name %0 is not covered by macro %1",
       (DeclName, DeclName))

lib/Sema/TypeCheckMacros.cpp

@@ -476,6 +476,14 @@ ExpandPeerMacroRequest::evaluate(Evaluator &evaluator, Decl *decl) const {
   return decl->getASTContext().AllocateCopy(bufferIDs);
 }
 
+static Identifier makeIdentifier(ASTContext &ctx, StringRef name) {
+  return ctx.getIdentifier(name);
+}
+
+static Identifier makeIdentifier(ASTContext &ctx, std::nullptr_t) {
+  return Identifier();
+}
+
 /// Diagnose macro expansions that produce any of the following declarations:
 ///   - Import declarations
 ///   - Operator and precedence group declarations
@@ -530,7 +538,17 @@ static void validateMacroExpansion(SourceFile *expansionBuffer,
 
     // Diagnose default literal type overrides.
     if (auto *typeAlias = dyn_cast<TypeAliasDecl>(decl)) {
-      // TODO
+      auto name = typeAlias->getBaseIdentifier();
+#define EXPRESSIBLE_BY_LITERAL_PROTOCOL_WITH_NAME(_, __, typeName,     \
+                                                  supportsOverride)    \
+      if (supportsOverride && name == makeIdentifier(ctx, typeName)) { \
+        typeAlias->diagnose(diag::literal_type_in_macro_expansion,     \
+                            makeIdentifier(ctx, typeName));            \
+        typeAlias->setInvalid();                                       \
+        continue;                                                      \
+      }
+#include "swift/AST/KnownProtocols.def"
+#undef EXPRESSIBLE_BY_LITERAL_PROTOCOL_WITH_NAME
     }
 
     // Diagnose value decls with names not covered by the macro

test/Macros/Inputs/syntax_macro_definitions.swift

@@ -781,6 +781,17 @@ public struct InvalidMacro: PeerMacro {
         static func main() {}
       }
       """,
+      "typealias Array = Void",
+      "typealias Dictionary = Void",
+      "typealias BooleanLiteralType = Void",
+      "typealias ExtendedGraphemeClusterType = Void",
+      "typealias FloatLiteralType = Void",
+      "typealias IntegerLiteralType = Void",
+      "typealias StringLiteralType = Void",
+      "typealias UnicodeScalarType = Void",
+      "typealias _ColorLiteralType = Void",
+      "typealias _ImageLiteralType = Void",
+      "typealias _FileReferenceLiteralType = Void",
     ]
   }
 }

test/Macros/macro_expand.swift

@@ -32,31 +32,47 @@ macro Invalid() = #externalMacro(module: "MacroDefinition", type: "InvalidMacro"
 
 @Invalid
 struct Bad {}
-// expected-note@-1 7 {{in expansion of macro 'Invalid' here}}
+// expected-note@-1 18 {{in expansion of macro 'Invalid' here}}
 
 // CHECK-DIAGS: error: macro expansion cannot introduce import
-// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
-// CHECK-DIAGS: import Swift
-
 // CHECK-DIAGS: error: macro expansion cannot introduce precedence group
-// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
-// CHECK-DIAGS: precedencegroup MyPrecedence {}
-
 // CHECK-DIAGS: error: macro expansion cannot introduce macro
-// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
-// CHECK-DIAGS: @attached(member) macro myMacro()
-
 // CHECK-DIAGS: error: macro expansion cannot introduce extension
-// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
-// CHECK-DIAGS: extension Int {}
+// CHECK-DIAGS: error: macro expansion cannot introduce '@main' type
+// CHECK-DIAGS: error: declaration name 'MyMain' is not covered by macro 'Invalid'
+// CHECK-DIAGS: error: declaration name 'Array' is not covered by macro 'Invalid'
+// CHECK-DIAGS: error: declaration name 'Dictionary' is not covered by macro 'Invalid'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'BooleanLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'ExtendedGraphemeClusterType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'FloatLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'IntegerLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'StringLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'UnicodeScalarType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_ColorLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_ImageLiteralType'
+// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_FileReferenceLiteralType'
 
-// CHECK-DIAGS: error: macro expansion cannot introduce '@main' type'
 // CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
+// CHECK-DIAGS: import Swift
+// CHECK-DIAGS: precedencegroup MyPrecedence {}
+// CHECK-DIAGS: @attached(member) macro myMacro()
+// CHECK-DIAGS: extension Int {}
 // CHECK-DIAGS: @main
-
-// CHECK-DIAGS: error: declaration name 'MyMain' is not covered by macro 'Invalid'
-// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3BadV7InvalidfMp_.swift
 // CHECK-DIAGS: struct MyMain {
+// CHECK-DIAGS:   static func main() {}
+// CHECK-DIAGS: }
+// CHECK-DIAGS: typealias Array = Void
+// CHECK-DIAGS: typealias Dictionary = Void
+// CHECK-DIAGS: typealias BooleanLiteralType = Void
+// CHECK-DIAGS: typealias ExtendedGraphemeClusterType = Void
+// CHECK-DIAGS: typealias FloatLiteralType = Void
+// CHECK-DIAGS: typealias IntegerLiteralType = Void
+// CHECK-DIAGS: typealias StringLiteralType = Void
+// CHECK-DIAGS: typealias UnicodeScalarType = Void
+// CHECK-DIAGS: typealias _ColorLiteralType = Void
+// CHECK-DIAGS: typealias _ImageLiteralType = Void
+// CHECK-DIAGS: typealias _FileReferenceLiteralType = Void
+// CHECK-DIAGS: END CONTENTS OF FILE
 #endif
 
 @freestanding(expression) macro customFileID() -> String = #externalMacro(module: "MacroDefinition", type: "FileIDMacro")