[clang-tools-extra] [clang-tidy] Improved cppcoreguidelines-pro-type-const-cast (PR #69501)

[Congcong Cai via cfe-commits]

================
@@ -14,13 +14,42 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
+static bool hasConstQualifier(QualType Type) {
+  const QualType PtrType = Type->getPointeeType();
+  if (!PtrType.isNull())
+    return hasConstQualifier(PtrType);
+
+  return Type.isConstQualified();
+}
+
+namespace {
+AST_MATCHER(QualType, hasConst) { return hasConstQualifier(Node); }
+} // namespace
+
+ProTypeConstCastCheck::ProTypeConstCastCheck(StringRef Name,
+                                             ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      StrictMode(Options.getLocalOrGlobal("StrictMode", false)) {}
+
+void ProTypeConstCastCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "StrictMode", StrictMode);
+}
+
 void ProTypeConstCastCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(cxxConstCastExpr().bind("cast"), this);
+  if (StrictMode)
+    Finder->addMatcher(cxxConstCastExpr().bind("cast"), this);
+  else
+    Finder->addMatcher(cxxConstCastExpr(unless(hasDestinationType(
+                                            hasCanonicalType(hasConst()))))
+                           .bind("cast"),
+                       this);
 }
 
 void ProTypeConstCastCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *MatchedCast = Result.Nodes.getNodeAs<CXXConstCastExpr>("cast");
-  diag(MatchedCast->getOperatorLoc(), "do not use const_cast");
+  diag(MatchedCast->getOperatorLoc(),
+       "do not use const_cast%select{ to cast away const|}0")
----------------
HerrCai0907 wrote:

`cast away const` sounds like a little bit strange.
```suggestion
       "do not use const_cast%select{ to remove const qualifier|}0")
```

https://github.com/llvm/llvm-project/pull/69501