Prevent modernize-use-auto from emitting a warning when 'auto' was already being used.

Summary: This fixes https://llvm.org/bugs/show_bug.cgi?id=25082 .

Reviewers: bkramer, klimek

Subscribers: cfe-commits, alexfh

Differential Revision: http://reviews.llvm.org/D13504

llvm-svn: 250284

clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp

@@ -222,6 +222,9 @@ StatementMatcher makeDeclWithNewMatcher() {
              has(varDecl()),
              unless(has(varDecl(anyOf(
                  unless(hasInitializer(ignoringParenImpCasts(cxxNewExpr()))),
+                 // Skip declarations that are already using auto.
+                 anyOf(hasType(autoType()),
+                       hasType(pointerType(pointee(autoType())))),
                  // FIXME: TypeLoc information is not reliable where CV
                  // qualifiers are concerned so these types can't be
                  // handled for now.

clang-tools-extra/test/clang-tidy/modernize-use-auto-new.cpp

@@ -95,4 +95,9 @@ void auto_new() {
     // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use auto when initializing with new
     // CHECK-FIXES: auto g = new int*, h = new int_p;
   }
+
+  // Don't warn when 'auto' is already being used.
+  auto aut = new MyType();
+  auto *paut = new MyType();
+  const auto *pcaut = new MyType();
 }