[clang-tidy] Fix invalid fixit for readability-static-accessed-through-instance (bug 40544)

[mgehre]

Summary

Fixed https://bugs.llvm.org/show_bug.cgi?id=40544
Before, we would generate a fixit like (anonymous namespace)::Foo::fun(); for
the added test case.

[aaron.ballman]

LGTM!

clang-tools-extra/trunk/clang-tidy/readability/StaticAccessedThroughInstanceCheck.cpp

void StaticAccessedThroughInstanceCheck::check(
   QualType BaseType =
       BaseExpr->getType()->isPointerType()
           ? BaseExpr->getType()->getPointeeType().getUnqualifiedType()
           : BaseExpr->getType().getUnqualifiedType();
 
   const ASTContext *AstContext = Result.Context;
   PrintingPolicy PrintingPolicyWithSupressedTag(AstContext->getLangOpts());
   PrintingPolicyWithSupressedTag.SuppressTagKeyword = true;
+  PrintingPolicyWithSupressedTag.SuppressUnwrittenScope = true;
   std::string BaseTypeName =
       BaseType.getAsString(PrintingPolicyWithSupressedTag);
 
   SourceLocation MemberExprStartLoc = MemberExpression->getBeginLoc();
   auto Diag =
       diag(MemberExprStartLoc, "static member accessed through instance");
 
   if (BaseExpr->HasSideEffects(*AstContext) ||

clang-tools-extra/trunk/test/clang-tidy/readability-static-accessed-through-instance.cpp

Q *operator->() {
     return q;
   }
 };
 
 int func(Qptr qp) {
   qp->y = 10; // OK, the overloaded operator might have side-effects.
   qp->K = 10; //
 }
+
+namespace {
+  struct Anonymous {
+    static int I;
+  };
+}
+
+void use_anonymous() {
+  Anonymous Anon;
+  Anon.I;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: static member
+  // CHECK-FIXES: {{^}}  Anonymous::I;{{$}}
+}
+
+namespace Outer {
+  inline namespace Inline {
+    struct S {
+      static int I;
+    };
+  }
+}
+
+void use_inline() {
+  Outer::S V;
+  V.I;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: static member
+  // CHECK-FIXES: {{^}}  Outer::S::I;{{$}}
+}