invert fallback logic

Author: salinas-miguel

lib/ClangImporter/ImportDecl.cpp

@@ -438,11 +438,18 @@ getSwiftStdlibType(const clang::TypedefNameDecl *D,
   else
     M = Impl.getNamedModule(SwiftModuleName);
 
+  if (!M) {
+    // User did not import the library module that contains the type we want to
+    // substitute.
+    *IsError = true;
+    return std::make_pair(Type(), "");
+  }
+
   Type SwiftType = Impl.getNamedSwiftType(M, SwiftTypeName);
 
   if (!SwiftType && CTypeKind == MappedCTypeKind::CGFloat) {
-    // Fall back to looking for CGFloat in Core Graphics.
-    M = Impl.getNamedModule("CoreGraphics");
+    // Look for CGFloat in CoreFoundation.
+    M = Impl.getNamedModule("CoreFoundation");
     SwiftType = Impl.getNamedSwiftType(M, SwiftTypeName);
   }
 

lib/ClangImporter/MappedTypes.def

@@ -156,7 +156,7 @@ MAP_STDLIB_TYPE(
   UnsignedWord, 0, "Int", false, DoNothing)
 
 // CGFloat.
-MAP_TYPE("CGFloat", CGFloat, 0, "CoreFoundation", "CGFloat", false, DoNothing)
+MAP_TYPE("CGFloat", CGFloat, 0, "CoreGraphics", "CGFloat", false, DoNothing)
 
 // CoreFoundation types.
 // Note that we're preserving the typealias for CFIndex.

test/PrintAsObjC/bridged-known-types-cf-cgfloat.swift

@@ -30,6 +30,3 @@ public class Test: NSObject {
   @objc public func isEnabled() -> Bool { true }
   // CHECK-NEXT: init
 } // CHECK-NEXT: @end
-// Rebuild modules without -DCGFLOAT_IN_COREFOUNDATION
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -emit-module -o %t %clang-importer-sdk-path/swift-modules/CoreFoundation.swift
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -emit-module -o %t %clang-importer-sdk-path/swift-modules/CoreGraphics.swift