[PATCH] D152796: [clang][Sema] Fix diagnostic message for unused constant varialbe templates

[Takuya Shimizu via Phabricator via cfe-commits]

hazohelet created this revision.
hazohelet added reviewers: aaron.ballman, tbaeder, shafik.
Herald added a project: All.
hazohelet requested review of this revision.
Herald added a project: clang.

BEFORE this patch, unused const-qualified variable templates such as `template <typename T> const double var_t = 0;` were diagnosed as `unused variable 'var_t'`
This patch fixes this message to `unused variable template 'var_t'`


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152796

Files:
  clang/docs/ReleaseNotes.rst
  clang/lib/Sema/Sema.cpp
  clang/test/SemaCXX/warn-unused-filescoped.cpp


Index: clang/test/SemaCXX/warn-unused-filescoped.cpp
===================================================================
--- clang/test/SemaCXX/warn-unused-filescoped.cpp
+++ clang/test/SemaCXX/warn-unused-filescoped.cpp
@@ -155,8 +155,7 @@
   int y = sizeof(d);
 
   namespace {
-  // FIXME: Should be "unused variable template 'var_t'" instead.
-  template <typename T> const double var_t = 0; // expected-warning {{unused variable 'var_t'}}
+  template <typename T> const double var_t = 0; // expected-warning {{unused variable template 'var_t'}}
   template <> const double var_t<int> = 0;      // expected-warning {{variable 'var_t<int>' is not needed and will not be emitted}}
   int z = sizeof(var_t<int>);                   // expected-warning {{unused variable 'z'}}
   }                                             // namespace
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -1380,6 +1380,9 @@
         if (DiagD->isReferenced()) {
           Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
               << /*variable*/ 1 << DiagD;
+        } else if (DiagD->getDescribedVarTemplate()) {
+          Diag(DiagD->getLocation(), diag::warn_unused_template)
+              << /*variable*/ 1 << DiagD;
         } else if (DiagD->getType().isConstQualified()) {
           const SourceManager &SM = SourceMgr;
           if (SM.getMainFileID() != SM.getFileID(DiagD->getLocation()) ||
@@ -1387,11 +1390,7 @@
             Diag(DiagD->getLocation(), diag::warn_unused_const_variable)
                 << DiagD;
         } else {
-          if (DiagD->getDescribedVarTemplate())
-            Diag(DiagD->getLocation(), diag::warn_unused_template)
-                << /*variable*/ 1 << DiagD;
-          else
-            Diag(DiagD->getLocation(), diag::warn_unused_variable) << DiagD;
+          Diag(DiagD->getLocation(), diag::warn_unused_variable) << DiagD;
         }
       }
     }
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -340,6 +340,8 @@
   can be controlled using ``-fcaret-diagnostics-max-lines=``.
 - Clang no longer emits ``-Wunused-variable`` warnings for variables declared
   with ``__attribute__((cleanup(...)))`` to match GCC's behavior.
+- Clang now diagnoses unused const-qualified variable template as
+  "unused variable template" rather than "unused variable".
 
 Bug Fixes in This Version
 -------------------------


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