3 files changed, 30 insertions, 17 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 24480fe81a0..3bea485c8fb 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -1761,7 +1761,8 @@ public:
   /// DiagnoseUnusedExprResult - If the statement passed in is an expression
   /// whose result is unused, warn.
   void DiagnoseUnusedExprResult(const Stmt *S);
-
+  void DiagnoseUnusedDecl(const NamedDecl *ND);
+  
   ParsingDeclStackState PushParsingDeclaration();
   void PopParsingDeclaration(ParsingDeclStackState S, DeclPtrTy D);
   void EmitDeprecationWarning(NamedDecl *D, SourceLocation Loc);
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index bf3c1724836..40ba8ffc195 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -544,9 +544,9 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
         return false;
     }
 
-    // If we failed to complete the type for some reason, don't
-    // diagnose the variable.
-    if (Ty->isIncompleteType())
+    // If we failed to complete the type for some reason, or if the type is
+    // dependent, don't diagnose the variable. 
+    if (Ty->isIncompleteType() || Ty->isDependentType())
       return false;
 
     if (const TagType *TT = Ty->getAs<TagType>()) {
@@ -555,9 +555,10 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
         return false;
 
       if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
-        if (!RD->hasTrivialConstructor())
-          return false;
-        if (!RD->hasTrivialDestructor())
+        // FIXME: Checking for the presence of a user-declared constructor
+        // isn't completely accurate; we'd prefer to check that the initializer
+        // has no side effects.
+        if (RD->hasUserDeclaredConstructor() || !RD->hasTrivialDestructor())
           return false;
       }
     }
@@ -568,6 +569,18 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
   return true;
 }
 
+void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {
+  if (!ShouldDiagnoseUnusedDecl(D))
+    return;
+  
+  if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
+    Diag(D->getLocation(), diag::warn_unused_exception_param)
+    << D->getDeclName();
+  else
+    Diag(D->getLocation(), diag::warn_unused_variable) 
+    << D->getDeclName();
+}
+
 void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
   if (S->decl_empty()) return;
   assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&
@@ -584,15 +597,9 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
     if (!D->getDeclName()) continue;
 
     // Diagnose unused variables in this scope.
-    if (ShouldDiagnoseUnusedDecl(D) && 
-        S->getNumErrorsAtStart() == getDiagnostics().getNumErrors()) {
-      if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
-        Diag(D->getLocation(), diag::warn_unused_exception_param)
-          << D->getDeclName();
-      else
-        Diag(D->getLocation(), diag::warn_unused_variable) 
-          << D->getDeclName();
-    }
+    if (S->getNumErrorsAtStart() == getDiagnostics().getNumErrors())
+      DiagnoseUnusedDecl(D);
+    
     // Remove this name from our lexical scope.
     IdResolver.RemoveDecl(D);
   }
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index a32c0e1ac32..d3d6c2209f5 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -351,7 +351,8 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
     Var->setLexicalDeclContext(D->getLexicalDeclContext());
 
   Var->setAccess(D->getAccess());
-
+  Var->setUsed(D->isUsed());
+  
   // FIXME: In theory, we could have a previous declaration for variables that
   // are not static data members.
   bool Redeclaration = false;
@@ -419,6 +420,10 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
   } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
     SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
 
+  // Diagnose unused local variables.
+  if (!Var->isInvalidDecl() && Owner->isFunctionOrMethod() && !Var->isUsed())
+    SemaRef.DiagnoseUnusedDecl(Var);
+  
   return Var;
 }