[clang] Fix the begin location of concepts specialization expression

[arphaman]

Summary

The concept specialization expression should start at the nested qualifiers location when it has nested qualifiers.
This ensures that libclang reports correct source ranges that include all subexpressions when visiting the expression.

[egorzhdan]

LGTM!

clang/include/clang/AST/ExprConcepts.h

const ASTConstraintSatisfaction &getSatisfaction() const {
     return *Satisfaction;
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ConceptSpecializationExprClass;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
+    if (auto QualifierLoc = getNestedNameSpecifierLoc())
+      return QualifierLoc.getBeginLoc();
     return ConceptName.getBeginLoc();
   }
 
   SourceLocation getEndLoc() const LLVM_READONLY {
     // If the ConceptSpecializationExpr is the ImmediatelyDeclaredConstraint
     // of a TypeConstraint written syntactically as a constrained-parameter,
     // there may not be a template argument list.
     return ArgsAsWritten->RAngleLoc.isValid() ? ArgsAsWritten->RAngleLoc

clang/test/Index/index-concepts.cpp

 
 }
 
 template <class T1, class T2>
 concept ConTwoTemplateParams = ns::ConInNamespace<T1> && ConWithLogicalAnd<T2>;
 // CHECK: index-concepts.cpp:[[@LINE-1]]:9: ConceptDecl=ConTwoTemplateParams:[[@LINE-1]]:9 (Definition) Extent=[[[@LINE-2]]:1 - [[@LINE-1]]:79]
 // CHECK: index-concepts.cpp:[[@LINE-3]]:17: TemplateTypeParameter=T1:[[@LINE-3]]:17 (Definition) Extent=[[[@LINE-3]]:11 - [[@LINE-3]]:19] [access=public]
 // CHECK: index-concepts.cpp:[[@LINE-4]]:27: TemplateTypeParameter=T2:[[@LINE-4]]:27 (Definition) Extent=[[[@LINE-4]]:21 - [[@LINE-4]]:29] [access=public]
-// CHECK: index-concepts.cpp:[[@LINE-4]]:36: BinaryOperator= Extent=[[[@LINE-4]]:36 - [[@LINE-4]]:79]
-// CHECK: index-concepts.cpp:[[@LINE-5]]:36: ConceptSpecializationExpr= Extent=[[[@LINE-5]]:36 - [[@LINE-5]]:54]
+// CHECK: index-concepts.cpp:[[@LINE-4]]:32: BinaryOperator= Extent=[[[@LINE-4]]:32 - [[@LINE-4]]:79]
+// CHECK: index-concepts.cpp:[[@LINE-5]]:32: ConceptSpecializationExpr= Extent=[[[@LINE-5]]:32 - [[@LINE-5]]:54]
 // CHECK: index-concepts.cpp:[[@LINE-6]]:32: NamespaceRef=ns:55:11 Extent=[[[@LINE-6]]:32 - [[@LINE-6]]:34]
 // CHECK: index-concepts.cpp:[[@LINE-7]]:36: TemplateRef=ConInNamespace:58:9 Extent=[[[@LINE-7]]:36 - [[@LINE-7]]:50]
 // CHECK: index-concepts.cpp:[[@LINE-8]]:58: ConceptSpecializationExpr= Extent=[[[@LINE-8]]:58 - [[@LINE-8]]:79]
 // CHECK: index-concepts.cpp:[[@LINE-9]]:58: TemplateRef=ConWithLogicalAnd:41:9 Extent=[[[@LINE-9]]:58 - [[@LINE-9]]:75]
 
 
 struct ConcreteType {};
 

 
 template<class T>
 void testTrailingRequires(const T &x)
 requires ns::ConInNamespace<T> && ConTwoTemplateParams<T, ConcreteType> {}
 // CHECK: index-concepts.cpp:[[@LINE-2]]:6: FunctionTemplate=testTrailingRequires:[[@LINE-2]]:6 (Definition) Extent=[[[@LINE-3]]:1 - [[@LINE-1]]:75]
 // CHECK: index-concepts.cpp:[[@LINE-4]]:16: TemplateTypeParameter=T:[[@LINE-4]]:16 (Definition) Extent=[[[@LINE-4]]:10 - [[@LINE-4]]:17] [access=public]
 // CHECK: index-concepts.cpp:[[@LINE-4]]:36: ParmDecl=x:[[@LINE-4]]:36 (Definition) Extent=[[[@LINE-4]]:27 - [[@LINE-4]]:37]
 // CHECK: index-concepts.cpp:[[@LINE-5]]:33: TypeRef=T:[[@LINE-6]]:16 Extent=[[[@LINE-5]]:33 - [[@LINE-5]]:34]
-// CHECK: index-concepts.cpp:[[@LINE-5]]:14: ConceptSpecializationExpr= Extent=[[[@LINE-5]]:14 - [[@LINE-5]]:31]
+// CHECK: index-concepts.cpp:[[@LINE-5]]:10: ConceptSpecializationExpr= Extent=[[[@LINE-5]]:10 - [[@LINE-5]]:31]
 // CHECK: index-concepts.cpp:[[@LINE-6]]:10: NamespaceRef=ns:55:11 Extent=[[[@LINE-6]]:10 - [[@LINE-6]]:12]
 // CHECK: index-concepts.cpp:[[@LINE-7]]:14: TemplateRef=ConInNamespace:58:9 Extent=[[[@LINE-7]]:14 - [[@LINE-7]]:28]
 // CHECK: index-concepts.cpp:[[@LINE-8]]:29: TypeRef=T:[[@LINE-10]]:16 Extent=[[[@LINE-8]]:29 - [[@LINE-8]]:30]
 // CHECK: index-concepts.cpp:[[@LINE-9]]:35: ConceptSpecializationExpr= Extent=[[[@LINE-9]]:35 - [[@LINE-9]]:72]
 // CHECK: index-concepts.cpp:[[@LINE-10]]:35: TemplateRef=ConTwoTemplateParams:63:9 Extent=[[[@LINE-10]]:35 - [[@LINE-10]]:55]
 // CHECK: index-concepts.cpp:[[@LINE-11]]:56: TypeRef=T:[[@LINE-13]]:16 Extent=[[[@LINE-11]]:56 - [[@LINE-11]]:57]
 // CHECK: index-concepts.cpp:[[@LINE-12]]:59: TypeRef=struct ConcreteType:75:8 Extent=[[[@LINE-12]]:59 - [[@LINE-12]]:71]