[SyntaxTree] Ignore implicit non-leaf `CXXConstructExpr`

Differential Revision: https://reviews.llvm.org/D86699

1 files changed, 24 insertions, 3 deletions

diff --git a/clang/lib/Tooling/Syntax/BuildTree.cpp b/clang/lib/Tooling/Syntax/BuildTree.cpp
index a9f3264..e5389ae 100644
--- a/clang/lib/Tooling/Syntax/BuildTree.cpp
+++ b/clang/lib/Tooling/Syntax/BuildTree.cpp
@@ -13,6 +13,7 @@
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
+#include "clang/AST/IgnoreExpr.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/TypeLoc.h"
@@ -44,8 +45,28 @@
 
 using namespace clang;
 
+// Ignores the implicit `CXXConstructExpr` for copy/move constructor calls
+// generated by the compiler, as well as in implicit conversions like the one
+// wrapping `1` in `X x = 1;`.
+static Expr *IgnoreImplicitConstructorSingleStep(Expr *E) {
+  if (auto *C = dyn_cast<CXXConstructExpr>(E)) {
+    auto NumArgs = C->getNumArgs();
+    if (NumArgs == 1 || (NumArgs > 1 && isa<CXXDefaultArgExpr>(C->getArg(1)))) {
+      Expr *A = C->getArg(0);
+      if (C->getParenOrBraceRange().isInvalid())
+        return A;
+    }
+  }
+  return E;
+}
+
+static Expr *IgnoreImplicit(Expr *E) {
+  return IgnoreExprNodes(E, IgnoreImplicitSingleStep,
+                         IgnoreImplicitConstructorSingleStep);
+}
+
 LLVM_ATTRIBUTE_UNUSED
-static bool isImplicitExpr(Expr *E) { return E->IgnoreImplicit() != E; }
+static bool isImplicitExpr(Expr *E) { return IgnoreImplicit(E) != E; }
 
 namespace {
 /// Get start location of the Declarator from the TypeLoc.
@@ -740,7 +761,7 @@ public:
       for (auto *D : DS->decls())
         Builder.noticeDeclWithoutSemicolon(D);
     } else if (auto *E = dyn_cast_or_null<Expr>(S)) {
-      return RecursiveASTVisitor::TraverseStmt(E->IgnoreImplicit());
+      return RecursiveASTVisitor::TraverseStmt(IgnoreImplicit(E));
     }
     return RecursiveASTVisitor::TraverseStmt(S);
   }
@@ -1579,7 +1600,7 @@ void syntax::TreeBuilder::markStmtChild(Stmt *Child, NodeRole Role) {
 void syntax::TreeBuilder::markExprChild(Expr *Child, NodeRole Role) {
   if (!Child)
     return;
-  Child = Child->IgnoreImplicit();
+  Child = IgnoreImplicit(Child);
 
   syntax::Tree *ChildNode = Mapping.find(Child);
   assert(ChildNode != nullptr);