[ClangImporter] Add check for Bool in importNumericLiteral

I somehow missed this in my original patch, make sure we also handle
the bool case here.

rdar://164916048

lib/ClangImporter/ClangImporter.cpp

@@ -440,6 +440,22 @@ bool importer::isForwardDeclOfType(const clang::Decl *D) {
   return false;
 }
 
+bool importer::isBoolOrBoolEnumType(Type ty) {
+  if (ty->isBool())
+    return true;
+
+  // Check if this is a C++ enum with an underlying type of "bool".
+  if (auto *SD = ty->getStructOrBoundGenericStruct()) {
+    if (auto *clangD = SD->getClangDecl()) {
+      if (auto *ED = dyn_cast<clang::EnumDecl>(clangD)) {
+        if (ED->getIntegerType()->isBooleanType())
+          return true;
+      }
+    }
+  }
+  return false;
+}
+
 bool ClangImporter::Implementation::shouldIgnoreBridgeHeaderTopLevelDecl(
     clang::Decl *D) {
   return importer::isForwardDeclOfType(D);

lib/ClangImporter/ImportMacro.cpp

@@ -146,15 +146,16 @@ static ValueDecl *importNumericLiteral(ClangImporter::Implementation &Impl,
       }
 
       // Make sure the destination type actually conforms to the builtin literal
-      // protocol before attempting to import, otherwise we'll crash since
-      // `createConstant` expects it to.
+      // protocol or is Bool before attempting to import, otherwise we'll crash
+      // since `createConstant` expects it to.
       // FIXME: We ought to be careful checking conformance here since it can
       // result in cycles. Additionally we ought to consider checking for the
       // non-builtin literal protocol to allow any ExpressibleByIntegerLiteral
       // type to be supported.
-      if (!ctx.getIntBuiltinInitDecl(constantTyNominal))
+      if (!isBoolOrBoolEnumType(constantType) &&
+          !ctx.getIntBuiltinInitDecl(constantTyNominal)) {
         return nullptr;
-
+      }
       return createMacroConstant(Impl, MI, name, DC, constantType,
                                  clang::APValue(value),
                                  ConstantConvertKind::None,

lib/ClangImporter/ImporterImpl.h

@@ -1985,6 +1985,10 @@ bool recordHasReferenceSemantics(const clang::RecordDecl *decl,
 /// declarations in certain cases, and instead process the real declarations.
 bool isForwardDeclOfType(const clang::Decl *decl);
 
+/// Checks whether this type is bool or is a C++ enum with a bool underlying
+/// type.
+bool isBoolOrBoolEnumType(Type ty);
+
 /// Whether we should suppress the import of the given Clang declaration.
 bool shouldSuppressDeclImport(const clang::Decl *decl);
 

lib/ClangImporter/SwiftDeclSynthesizer.cpp

@@ -276,16 +276,9 @@ ValueDecl *SwiftDeclSynthesizer::createConstant(Identifier name,
     // Create the expression node.
     StringRef printedValueCopy(context.AllocateCopy(printedValue));
     if (value.getKind() == clang::APValue::Int) {
-      bool isBool = type->getCanonicalType()->isBool();
-      // Check if "type" is a C++ enum with an underlying type of "bool".
-      if (!isBool && type->getStructOrBoundGenericStruct() &&
-          type->getStructOrBoundGenericStruct()->getClangDecl()) {
-        if (auto enumDecl = dyn_cast<clang::EnumDecl>(
-                type->getStructOrBoundGenericStruct()->getClangDecl())) {
-          isBool = enumDecl->getIntegerType()->isBooleanType();
-        }
-      }
-      if (isBool) {
+      // Check if "type" is Bool or a C++ enum with an underlying type of Bool.
+      // NOTE: This must match the condition in `importNumericLiteral`.
+      if (isBoolOrBoolEnumType(type)) {
         auto *boolExpr = new (context)
             BooleanLiteralExpr(value.getInt().getBoolValue(), SourceLoc(),
                                /*Implicit=*/true);

test/ClangImporter/macro_bool_constants.swift

@@ -0,0 +1,39 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-sil %t/valid.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify %t/invalid.swift -I %t -disable-typo-correction
+
+// REQUIRES: objc_interop
+// REQUIRES: OS=macosx
+
+//--- cmodule.h
+#include <stdbool.h>
+
+typedef _Bool UnderscoreBoolAlias;
+#define usesUnderscoreBoolAlias ((UnderscoreBoolAlias)0)
+#define usesUnderscoreBool ((_Bool)0)
+
+typedef bool BoolAlias;
+#define usesBoolAlias ((BoolAlias)0)
+#define usesBool ((bool)0)
+
+//--- module.modulemap
+module CModule {
+  header "cmodule.h"
+  requires objc
+  export *
+}
+
+//--- valid.swift
+import CModule
+
+// Make sure we can import these constants.
+print(usesUnderscoreBoolAlias)
+print(usesBoolAlias)
+
+//--- invalid.swift
+import CModule
+
+// FIXME: These ought to work too
+print(usesUnderscoreBool) // expected-error {{cannot find 'usesUnderscoreBool' in scope}}
+print(usesBool) // expected-error {{cannot find 'usesBool' in scope}}