[ObjC] Correctly decode block pointers in the method type encoding

The compiler represents block parameters as `@?` in the method type
encoding string. We had been parsing this as two separate parameters
(one `id` and one unknown type that was mapped to `void*`), resulting in
some Objective-C method implementations incorrectly having an extra
parameter.

We cannot represent a Clang block (e.g., `void (^)()`) in the type
system at present. Since these are Objective-C compatible types the
simplest solution for now is to represent them as `id`.

1 files changed, 8 insertions, 0 deletions

diff --git a/objectivec/objc.cpp b/objectivec/objc.cpp
index 4e36c9ed..1da2cb34 100644
--- a/objectivec/objc.cpp
+++ b/objectivec/objc.cpp
@@ -340,6 +340,14 @@ std::vector<QualifiedNameOrType> ObjCProcessor::ParseEncodedType(const std::stri
 			qualifiedName = "objc_class_t";
 			break;
 		case '?':
+			if (last == '@')
+			{
+				// A pointer to a Clang block is encoded as `@?`. For now we continue to represent this
+				// as `id` as we cannot represent block types.
+				last = c;
+				continue;
+			}
+			[[fallthrough]];
 		case 'T':
 			nameOrType.type = Type::PointerType(8, Type::VoidType());
 			break;