[Sema] -Wunused-variable warning for array variables should behave

similarly to scalar variables.

This commit makes the -Wunused-variable warning behaviour more consistent:
Now clang won't warn for array variables where it doesn't warn for scalar
variables.

rdar://24158862

Differential Revision: https://reviews.llvm.org/D25937

llvm-svn: 285289

1 files changed, 5 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index c8973ae100e..a94ed532944 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -1522,7 +1522,7 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
   if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
 
     // White-list anything with an __attribute__((unused)) type.
-    QualType Ty = VD->getType();
+    const auto *Ty = VD->getType().getTypePtr();
 
     // Only look at the outermost level of typedef.
     if (const TypedefType *TT = Ty->getAs<TypedefType>()) {
@@ -1535,6 +1535,10 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
     if (Ty->isIncompleteType() || Ty->isDependentType())
       return false;
 
+    // Look at the element type to ensure that the warning behaviour is
+    // consistent for both scalars and arrays.
+    Ty = Ty->getBaseElementTypeUnsafe();
+
     if (const TagType *TT = Ty->getAs<TagType>()) {
       const TagDecl *Tag = TT->getDecl();
       if (Tag->hasAttr<UnusedAttr>())