[clangd] Handle OverloadExpr in targetDecl

clang-tools-extra/clangd/FindTarget.cpp

struct Visitor : public ConstStmtVisitor<Visitor> {
       }
       void VisitMemberExpr(const MemberExpr *ME) {
         const Decl *D = ME->getMemberDecl();
         if (auto *USD =
                 llvm::dyn_cast<UsingShadowDecl>(ME->getFoundDecl().getDecl()))
           D = USD;
         Outer.add(D, Flags);
       }
+      void VisitOverloadExpr(const OverloadExpr *OE) {
+        for (auto *D : OE->decls())
+          Outer.add(D, Flags);
+      }
       void VisitCXXConstructExpr(const CXXConstructExpr *CCE) {
         Outer.add(CCE->getConstructor(), Flags);
       }
       void VisitDesignatedInitExpr(const DesignatedInitExpr *DIE) {
         for (const DesignatedInitExpr::Designator &D :
              llvm::reverse(DIE->designators()))
           if (D.isFieldDesignator()) {
             Outer.add(D.getField(), Flags);

clang-tools-extra/clangd/unittests/FindTargetTests.cpp

Code = R"cpp(
     void foo() {
       auto l = [x = 1]{ return [[x]] + 1; };
     };
   )cpp";
   // FIXME: why both auto and int?
   EXPECT_DECLS("DeclRefExpr", "auto int x = 1");
 }
 
+TEST_F(TargetDeclTest, OverloadExpr) {
+  Code = R"cpp(
+    void func(int*);
+    void func(char*);
+
+    template <class T>
+    void foo(T t) {
+      [[func]](t);
+    };
+  )cpp";
+  EXPECT_DECLS("UnresolvedLookupExpr", "void func(int *)", "void func(char *)");
+
+  Code = R"cpp(
+    struct X {
+      void func(int*);
+      void func(char*);
+    };
+
+    template <class T>
+    void foo(X x, T t) {
+      x.[[func]](t);
+    };
+  )cpp";
+  EXPECT_DECLS("UnresolvedMemberExpr", "void func(int *)", "void func(char *)");
+}
+
 TEST_F(TargetDeclTest, ObjC) {
   Flags = {"-xobjective-c"};
   Code = R"cpp(
     @interface Foo {}
     -(void)bar;
     @end
     void test(Foo *f) {
       [f [[bar]] ];