From 6f135344102bde8d81237cef04ea3d4e1a1b8b46 Mon Sep 17 00:00:00 2001
From: Alex Lorenz <arphaman@gmail.com>
Date: Fri, 25 Aug 2017 16:12:17 +0000
Subject: [PATCH] [ObjC] Add a -Wobjc-messaging-id warning
-Wobjc-messaging-id is a new, non-default warning that warns about
message sends to unqualified id in Objective-C. This warning is useful
for projects that would like to avoid any potential future compiler
errors/warnings, as the system frameworks might add a method with the same
selector which could make the message send to id ambiguous.
rdar://33303354
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311779 91177308-0d34-0410-b5e6-96231b3b80d8
---
docs/ReleaseNotes.rst | 6 ++++++
include/clang/Basic/DiagnosticSemaKinds.td | 4 ++++
lib/Sema/SemaExprObjC.cpp | 3 +++
test/SemaObjC/warn-messaging-id.mm | 21 +++++++++++++++++++++
4 files changed, 34 insertions(+)
create mode 100644 test/SemaObjC/warn-messaging-id.mm
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index be038234df7..45bf166068a 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -66,6 +66,12 @@ Improvements to Clang's diagnostics
a non-default alignment that has been specified using a ``#pragma pack``
directive prior to the ``#include``.
+- ``-Wobjc-messaging-id`` is a new, non-default warning that warns about
+ message sends to unqualified ``id`` in Objective-C. This warning is useful
+ for projects that would like to avoid any potential future compiler
+ errors/warnings, as the system frameworks might add a method with the same
+ selector which could make the message send to ``id`` ambiguous.
+
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 37066b46786..04576b60a0e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1211,6 +1211,10 @@ def err_objc_method_unsupported_param_ret_type : Error<
"%0 %select{parameter|return}1 type is unsupported; "
"support for vector types for this target is introduced in %2">;
+def warn_messaging_unqualified_id : Warning<
+ "messaging unqualified id">, DefaultIgnore,
+ InGroup<DiagGroup<"objc-messaging-id">>;
+
// C++ declarations
def err_static_assert_expression_is_not_constant : Error<
"static_assert expression is not an integral constant expression">;
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index 28581bad1a7..83ef799392a 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -2705,6 +2705,9 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
}
}
+ if (ReceiverType->isObjCIdType() && !isImplicit)
+ Diag(Receiver->getExprLoc(), diag::warn_messaging_unqualified_id);
+
// There's a somewhat weird interaction here where we assume that we
// won't actually have a method unless we also don't need to do some
// of the more detailed type-checking on the receiver.
diff --git a/test/SemaObjC/warn-messaging-id.mm b/test/SemaObjC/warn-messaging-id.mm
new file mode 100644
index 00000000000..8112cfa3d52
--- /dev/null
+++ b/test/SemaObjC/warn-messaging-id.mm
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class -Wobjc-messaging-id %s
+
+@interface CallMeMaybe
+
+- (void)doThing:(int)intThing;
+
+@property int thing;
+
+@end
+
+template<typename T>
+void instantiate(const T &x) {
+ [x setThing: 22]; // expected-warning {{messaging unqualified id}}
+}
+
+void fn() {
+ id myObject;
+ [myObject doThing: 10]; // expected-warning {{messaging unqualified id}}
+ [myObject setThing: 11]; // expected-warning {{messaging unqualified id}}
+ instantiate(myObject); // expected-note {{in instantiation}}
+}
--
GitLab