[clang-tools-extra] [clang-tidy] Create bugprone-bit-cast-pointers check (PR #108083)

[Julian Schmidt via cfe-commits]

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@@ -0,0 +1,32 @@
+//===--- BitCastPointersCheck.cpp - clang-tidy ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "BitCastPointersCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+void BitCastPointersCheck::registerMatchers(MatchFinder *Finder) {
+  auto IsPointerType = refersToType(qualType(isAnyPointer()));
+  Finder->addMatcher(callExpr(callee(functionDecl(allOf(
+                                  hasName("::std::bit_cast"),
+                                  hasTemplateArgument(0, IsPointerType),
+                                  hasTemplateArgument(1, IsPointerType)))))
+                         .bind("x"),
+                     this);
+}
+
+void BitCastPointersCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *MatchedDecl = Result.Nodes.getNodeAs<CallExpr>("x"))
----------------
5chmidti wrote:

> Note that the `getNodeAs` can return a nullptr even if there is a match, but it was not possible to cast to the chosen type.

true

> it's done in many tidy checks and is cheap to do

I think some of the newer ones don't do that, but yes, it is cheap.

https://github.com/llvm/llvm-project/pull/108083