Fix traversal with hasDescendant into lambdas

[alexfh]

Looks good!

clang/lib/ASTMatchers/ASTMatchFinder.cpp

bool TraverseLambdaExpr(LambdaExpr *Node) {
     for (const auto *P : Node->getCallOperator()->parameters()) {
       if (!match(*P))
         return false;
     }
 
     if (!match(*Node->getBody()))
       return false;
 
-    return true;
+    return VisitorBase::TraverseStmt(Node->getBody());
   }
 
   bool shouldVisitTemplateInstantiations() const { return true; }
   bool shouldVisitImplicitCode() const { return !IgnoreImplicitChildren; }
 
 private:
   // Used for updating the depth during traversal.
   struct ScopedIncrement {

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

void func13() {
   [a, b = c](int d) { int e = d; };
 }
 
 void func14() {
   [] <typename TemplateType> (TemplateType t, TemplateType u) { int e = t + u; };
   float i = 42.0;
 }
 
+void func15() {
+  int count = 0;
+  auto l = [&] { ++count; };
+  (void)l;
+}
+
 )cpp";
 
   EXPECT_TRUE(
       matches(Code,
               traverse(TK_IgnoreUnlessSpelledInSource,
                        returnStmt(forFunction(functionDecl(hasName("func1"))),
                                   hasReturnValue(integerLiteral(equals(42))))),
               langCxx20OrLater()));
EXPECT_TRUE(matches(
       langCxx20OrLater()));
 
   EXPECT_TRUE(matches(
       Code,
       traverse(TK_IgnoreUnlessSpelledInSource,
                functionDecl(hasName("func14"), hasDescendant(floatLiteral()))),
       langCxx20OrLater()));
 
+  EXPECT_TRUE(matches(
+      Code,
+      traverse(TK_IgnoreUnlessSpelledInSource,
+               compoundStmt(
+                   hasDescendant(varDecl(hasName("count")).bind("countVar")),
+                   hasDescendant(
+                       declRefExpr(to(varDecl(equalsBoundNode("countVar"))))))),
+      langCxx20OrLater()));
+
   Code = R"cpp(
 void foo() {
     int explicit_captured = 0;
     int implicit_captured = 0;
     auto l = [&, explicit_captured](int i) {
         if (i || explicit_captured || implicit_captured) return;
     };
 }