[PATCH] D126853: [clang-tidy] `bugprone-use-after-move`: Don't warn on self-moves.

[Martin Böhme via Phabricator via cfe-commits]

mboehme created this revision.
Herald added subscribers: carlosgalvezp, xazax.hun.
Herald added a project: All.
mboehme requested review of this revision.
Herald added a project: clang-tools-extra.
Herald added a subscriber: cfe-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126853

Files:
  clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/bugprone-use-after-move.cpp


Index: clang-tools-extra/test/clang-tidy/checkers/bugprone-use-after-move.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/bugprone-use-after-move.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone-use-after-move.cpp
@@ -152,6 +152,13 @@
   // CHECK-NOTES: [[@LINE-3]]:15: note: move occurred here
 }
 
+// Don't flag a move-to-self.
+void selfMove() {
+  A a;
+  a = std::move(a);
+  a.foo();
+}
+
 // A warning should only be emitted for one use-after-move.
 void onlyFlagOneUseAfterMove() {
   A a;
Index: clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
+++ clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
@@ -158,9 +158,12 @@
 
   // Ignore all reinitializations where the move potentially comes after the
   // reinit.
+  // If `Reinit` is identical to `MovingCall`, we're looking at a move-to-self
+  // (e.g. `a = std::move(a)`). Count these as reinitializations.
   llvm::SmallVector<const Stmt *, 1> ReinitsToDelete;
   for (const Stmt *Reinit : Reinits) {
-    if (MovingCall && Sequence->potentiallyAfter(MovingCall, Reinit))
+    if (MovingCall && Reinit != MovingCall &&
+        Sequence->potentiallyAfter(MovingCall, Reinit))
       ReinitsToDelete.push_back(Reinit);
   }
   for (const Stmt *Reinit : ReinitsToDelete) {


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