[clang-tools-extra] [clang-tidy] modernize-use-nullptr matches "NULL" in templates (PR #109169)

[Thomas Köppe via cfe-commits]

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@@ -38,7 +38,9 @@ AST_MATCHER(Type, sugaredNullptrType) {
 StatementMatcher makeCastSequenceMatcher(llvm::ArrayRef<StringRef> NameList) {
   auto ImplicitCastToNull = implicitCastExpr(
       anyOf(hasCastKind(CK_NullToPointer), hasCastKind(CK_NullToMemberPointer)),
-      unless(hasImplicitDestinationType(qualType(substTemplateTypeParmType()))),
+      anyOf(hasSourceExpression(gnuNullExpr()),
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tkoeppe wrote:

This is explained somewhat in the unit test: When `NULL` is defined to `__null`, then this change will catch both cases. But we don't have a direct check for "the origin was the macro `NULL`", I'm afraid. @zygoloid suggested this change as a reasonable, small change that will be effective in many real-world cases.

I'd be happy to have a more general solution, but couldn't find one, and the present one will already do a lot of good. What do you think?

https://github.com/llvm/llvm-project/pull/109169