[clang] b0697a1 - Create diagnostic group for definition deprecation warning

[Aaron Ballman via cfe-commits]

Author: Nuri Amari
Date: 2023-07-16T12:36:26-04:00
New Revision: b0697a1cb0b539c773548f62402816e2d9b6f107

URL: https://github.com/llvm/llvm-project/commit/b0697a1cb0b539c773548f62402816e2d9b6f107
DIFF: https://github.com/llvm/llvm-project/commit/b0697a1cb0b539c773548f62402816e2d9b6f107.diff

LOG: Create diagnostic group for definition deprecation warning

In https://reviews.llvm.org/D126664, a warning is introduced
warning against the deprecated out of line definition of a
static constexpr member in C++17 and later. Prior to this patch,
the only diagnostic group controlling this diagnostic was -Wdeprecated,
which controls many many diagnostics. This patch creates
a diagnostic group specifically for this warning so it can
be controlled in isolation, while also being included with -Wdeprecated.

Differential Revision: https://reviews.llvm.org/D153881

Added: 
    clang/test/SemaCXX/redundant-out-of-line-static-constexpr-member-def-diag.cpp

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Basic/DiagnosticGroups.td
    clang/include/clang/Basic/DiagnosticSemaKinds.td

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c501903815955d..8f3bd70f7a2aa1 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -386,6 +386,13 @@ Improvements to Clang's diagnostics
   on overload resolution, when the actual reason for the failure is loss of other qualifiers.
 - Clang's notes about unconvertible types in overload resolution failure now covers
   the source range of parameter declaration of the candidate function declaration.
+- Added a new diagnostic warning group
+  ``-Wdeprecated-redundant-constexpr-static-def``, under the existing
+  ``-Wdeprecated`` group. This controls warnings about out-of-line definitions
+  of 'static constexpr' data members that are unnecessary from C++17 onwards.
+
+ Bug Fixes in This Version
+ -------------------------
 
   *Example Code*:
 

diff  --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index cfc1c9bc15bd2d..c0797166585e44 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -186,6 +186,7 @@ def DeprecatedCopyWithDtor : DiagGroup<"deprecated-copy-with-dtor", [DeprecatedC
 // For compatibility with GCC.
 def : DiagGroup<"deprecated-copy-dtor", [DeprecatedCopyWithDtor]>;
 def DeprecatedDeclarations : DiagGroup<"deprecated-declarations">;
+def DeprecatedRedundantConstexprStaticDef : DiagGroup<"deprecated-redundant-constexpr-static-def">;
 def UnavailableDeclarations : DiagGroup<"unavailable-declarations">;
 def UnguardedAvailabilityNew : DiagGroup<"unguarded-availability-new">;
 def UnguardedAvailability : DiagGroup<"unguarded-availability",
@@ -224,7 +225,9 @@ def Deprecated : DiagGroup<"deprecated", [DeprecatedAnonEnumEnumConversion,
                                           DeprecatedThisCapture,
                                           DeprecatedType,
                                           DeprecatedVolatile,
-                                          DeprecatedWritableStr]>,
+                                          DeprecatedWritableStr,
+                                          DeprecatedRedundantConstexprStaticDef,
+                                          ]>,
                  DiagCategory<"Deprecations">;
 
 def CXX20Designator : DiagGroup<"c++20-designator">;

diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index eea4d4961c077a..d9932e0aa31a2a 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -447,7 +447,7 @@ def warn_qual_return_type : Warning<
 def warn_deprecated_redundant_constexpr_static_def : Warning<
   "out-of-line definition of constexpr static data member is redundant "
   "in C++17 and is deprecated">,
-  InGroup<Deprecated>, DefaultIgnore;
+  InGroup<DeprecatedRedundantConstexprStaticDef>, DefaultIgnore;
 
 def warn_decl_shadow :
   Warning<"declaration shadows a %select{"

diff  --git a/clang/test/SemaCXX/redundant-out-of-line-static-constexpr-member-def-diag.cpp b/clang/test/SemaCXX/redundant-out-of-line-static-constexpr-member-def-diag.cpp
new file mode 100644
index 00000000000000..873fbf1b32cac3
--- /dev/null
+++ b/clang/test/SemaCXX/redundant-out-of-line-static-constexpr-member-def-diag.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -std=c++17 -verify %s -Werror -Wdeprecated -Wno-error=deprecated-redundant-constexpr-static-def
+
+namespace {
+  struct A {
+    static constexpr int n = 0;
+    static constexpr int m = 0;
+  };
+  constexpr int A::n; // expected-warning{{out-of-line definition of constexpr static data member is redundant in C++17 and is deprecated}}
+  const int A::m; // expected-warning{{out-of-line definition of constexpr static data member is redundant in C++17 and is deprecated}}
+}