Do not diagnose unused-parameter errors in template instantiations. We

will already have done so when the template is declared.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101838 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 33 insertions, 1 deletions

diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index a95d08262e..0535923d6b 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -853,12 +853,18 @@ public:
     if (Diags.getDiagnosticLevel(diag::warn_unused_parameter) == 
           Diagnostic::Ignored)
       return;
+
+    // Don't diagnose unused-parameter errors in template instantiations; we
+    // will already have done so in the template itself.
+    if (!ActiveTemplateInstantiations.empty())
+      return;
     
     for (; Param != ParamEnd; ++Param) {
       if (!(*Param)->isUsed() && (*Param)->getDeclName() &&
-          !(*Param)->template hasAttr<UnusedAttr>())
+          !(*Param)->template hasAttr<UnusedAttr>()) {
         Diag((*Param)->getLocation(), diag::warn_unused_parameter)
           << (*Param)->getDeclName();
+      }
     }
   }
 
diff --git a/test/SemaCXX/warn-unused-parameters.cpp b/test/SemaCXX/warn-unused-parameters.cpp
new file mode 100644
index 0000000000..75d8dcc549
--- /dev/null
+++ b/test/SemaCXX/warn-unused-parameters.cpp
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -fsyntax-only -Wunused-parameter -verify %s
+template<typename T>
+struct X {
+  T f0(T x);
+  T f1(T x);
+  T f2(T);
+  template<typename U> U f3(U x);
+  template<typename U> U f4(U x);
+  template<typename U> U f5(U);
+};
+
+template<typename T> T X<T>::f0(T x) { return x; }
+template<typename T> T X<T>::f1(T) { return T(); }
+template<typename T> T X<T>::f2(T x) { return T(); } // expected-warning{{unused parameter 'x'}}
+template<typename T> template<typename U> U X<T>::f3(U x) { return x; }
+template<typename T> template<typename U> U X<T>::f4(U) { return U(); }
+template<typename T> template<typename U> U X<T>::f5(U x) { return U(); } // expected-warning{{unused parameter 'x'}}
+
+void test_X(X<int> &x, int i) {
+  x.f0(i);
+  x.f1(i);
+  x.f2(i);
+  x.f3(i);
+  x.f4(i);
+  x.f5(i);
+}