[Index] Use locations to uniquify function-scope BindingDecl USR

[MaskRay]

Summary

This makes BindingDecl's of the same name have different USRs, so that references can be correctly attributed.

int a[1] = {};
{ auto [x] = a; x; }
{ auto [x] = a; x; }

[MaskRay]

Ping

[hokein]

Can you add a test?

[MaskRay]

Add test to Core/index-source.cpp

[hokein]

The change looks reasonable to me, so lg. I'd wait a bit to see whether other reviewers have comments.

lib/Index/USRGeneration.cpp

339

use isLocal(D) instead.

[MaskRay]

Use isLocal

lib/Index/USRGeneration.cpp

void VisitObjCContainerDecl(const ObjCContainerDecl *CD,
                               const ObjCCategoryDecl *CatD = nullptr);
   void VisitObjCMethodDecl(const ObjCMethodDecl *MD);
   void VisitObjCPropertyDecl(const ObjCPropertyDecl *D);
   void VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D);
   void VisitTagDecl(const TagDecl *D);
   void VisitTypedefDecl(const TypedefDecl *D);
   void VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D);
   void VisitVarDecl(const VarDecl *D);
+  void VisitBindingDecl(const BindingDecl *D);
   void VisitNonTypeTemplateParmDecl(const NonTypeTemplateParmDecl *D);
   void VisitTemplateTemplateParmDecl(const TemplateTemplateParmDecl *D);
   void VisitUnresolvedUsingValueDecl(const UnresolvedUsingValueDecl *D);
   void VisitUnresolvedUsingTypenameDecl(const UnresolvedUsingTypenameDecl *D);
 
   void VisitLinkageSpecDecl(const LinkageSpecDecl *D) {
     IgnoreResults = true; // No USRs for linkage specs themselves.
   }
if (const VarTemplateSpecializationDecl *Spec
     Out << '>';
     for (unsigned I = 0, N = Args.size(); I != N; ++I) {
       Out << '#';
       VisitTemplateArgument(Args.get(I));
     }
   }
 }
 
+void USRGenerator::VisitBindingDecl(const BindingDecl *D) {
+  if (D->getParentFunctionOrMethod() && GenLoc(D, /*IncludeOffset=*/true))
+    return;
+  VisitNamedDecl(D);
+}
+
 void USRGenerator::VisitNonTypeTemplateParmDecl(
                                         const NonTypeTemplateParmDecl *D) {
   GenLoc(D, /*IncludeOffset=*/true);
 }
 
 void USRGenerator::VisitTemplateTemplateParmDecl(
                                         const TemplateTemplateParmDecl *D) {
   GenLoc(D, /*IncludeOffset=*/true);