[clang-tools-extra] [clang-tidy] Fix false positive in bugprone-use-after-move for std::tie (PR #192895)

[Baranov Victor via cfe-commits]

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@@ -1789,4 +1790,55 @@ void Run() {
   RegularReset(db6);
   db6.Query();
 }
+
 } // namespace custom_reinitialization
+
+// Tests for std::tie() reinitialization.
+std::pair<std::string, std::string> makeStringPair(std::string a,
+                                                   std::string b);
+
+void stdTieIsReinit() {
+  // std::tie on the LHS reinitializes all captured variables.
+  std::string a, b;
+  std::move(a);
+  std::move(b);
+  std::tie(a, b) = makeStringPair("x", "y"); // no-warning: both reinitialized
+  a.size();
+  b.size();
+}
+
+void stdTieWithIgnore() {
+  // std::ignore placeholder does not prevent reinitialization of named variables.
+  std::string a;
+  std::move(a);
+  std::tie(a, std::ignore) = makeStringPair("x", "y"); // no-warning: a reinitialized
+  a.size();
+}
+
+void stdTieIgnoreFlipped() {
+  // std::ignore in first position still reinitializes named variables.
+  std::string a;
+  std::move(a);
+  std::tie(std::ignore, a) = makeStringPair("x", "y"); // no-warning: a reinitialized
+  a.size();
+}
+
+void stdTiePartialReinit() {
+  // Only variables named in std::tie are reinitialized.
+  std::string a, b;
+  std::move(a);
+  std::tie(b) = std::make_tuple(std::string("y")); // reinitializes b, not a
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vbvictor wrote:

can add another test with `tie(c, b, ignore); a.size(), b.size()`.

https://github.com/llvm/llvm-project/pull/192895