[PATCH] D143524: Make the -Wunused-template default.

[Vassil Vassilev via Phabricator via cfe-commits]

v.g.vassilev created this revision.
v.g.vassilev added reviewers: aaron.ballman, ldionne.
Herald added a project: All.
v.g.vassilev requested review of this revision.

https://reviews.llvm.org/D29877 implements a useful -Wunused-template diagnostic detects unused internal linkage templates. This helps finding potential ODR issues in headers.

Many years ago we made the diagnostic optional because libcxx was not ready. I am hoping @ldionne to help with that if we have not cleaned up libcxx already.


Repository:
  rC Clang

https://reviews.llvm.org/D143524

Files:
  clang/include/clang/Basic/DiagnosticGroups.td
  clang/test/Misc/warning-wall.c
  clang/test/SemaCXX/warn-func-not-needed.cpp
  clang/test/SemaCXX/warn-variable-not-needed.cpp


Index: clang/test/SemaCXX/warn-variable-not-needed.cpp
===================================================================
--- clang/test/SemaCXX/warn-variable-not-needed.cpp
+++ clang/test/SemaCXX/warn-variable-not-needed.cpp
@@ -4,7 +4,7 @@
   static int abc = 42; // expected-warning {{variable 'abc' is not needed and will not be emitted}}
 
   namespace {
-  template <typename T> int abc_template = 0;
+  template <typename T> int abc_template = 0; //expected-warning {{unused variable template}}
   template <> int abc_template<int> = 0; // expected-warning {{variable 'abc_template<int>' is not needed and will not be emitted}}
   }                                      // namespace
   template <typename T>
Index: clang/test/SemaCXX/warn-func-not-needed.cpp
===================================================================
--- clang/test/SemaCXX/warn-func-not-needed.cpp
+++ clang/test/SemaCXX/warn-func-not-needed.cpp
@@ -10,7 +10,7 @@
 }
 
 namespace test1_template {
-template <typename T> static void f() {}
+template <typename T> static void f() {} // expected-warning {{unused function template}}
 template <> void f<int>() {} // expected-warning {{function 'f<int>' is not needed and will not be emitted}}
 template <typename T>
 void foo() {
Index: clang/test/Misc/warning-wall.c
===================================================================
--- clang/test/Misc/warning-wall.c
+++ clang/test/Misc/warning-wall.c
@@ -66,6 +66,8 @@
 CHECK-NEXT:      -Wunused-function
 CHECK-NEXT:        -Wunneeded-internal-declaration
 CHECK-NEXT:      -Wunused-label
+CHECK-NEXT:      -Wunused-template
+CHECK-NEXT:        -Wunneeded-internal-declaration
 CHECK-NEXT:      -Wunused-private-field
 CHECK-NEXT:      -Wunused-lambda-capture
 CHECK-NEXT:      -Wunused-local-typedef
Index: clang/include/clang/Basic/DiagnosticGroups.td
===================================================================
--- clang/include/clang/Basic/DiagnosticGroups.td
+++ clang/include/clang/Basic/DiagnosticGroups.td
@@ -929,7 +929,7 @@
 def Unused : DiagGroup<"unused",
                        [UnusedArgument, UnusedFunction, UnusedLabel,
                         // UnusedParameter, (matches GCC's behavior)
-                        // UnusedTemplate, (clean-up libc++ before enabling)
+                        UnusedTemplate,
                         // UnusedMemberFunction, (clean-up llvm before enabling)
                         UnusedPrivateField, UnusedLambdaCapture,
                         UnusedLocalTypedef, UnusedValue, UnusedVariable,


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