[clang] Fix the begin location of concepts specialization expression

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

Differential Revision: https://reviews.llvm.org/D126332

Author: hyp

clang/include/clang/AST/ExprConcepts.h

@@ -122,6 +122,8 @@ class ConceptSpecializationExpr final : public Expr, public ConceptReference,
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
+    if (auto QualifierLoc = getNestedNameSpecifierLoc())
+      return QualifierLoc.getBeginLoc();
     return ConceptName.getBeginLoc();
   }
 

clang/test/Index/index-concepts.cpp

@@ -64,8 +64,8 @@ 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]
@@ -107,7 +107,7 @@ requires ns::ConInNamespace<T> && ConTwoTemplateParams<T, ConcreteType> {}
 // 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]