[PATCH] D54405: Record whether a AST Matcher constructs a Node

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added a comment.

Aside from the uses of auto and the lack of tests, this LGTM.



================
Comment at: lib/ASTMatchers/Dynamic/Registry.cpp:77
+      internal::MatcherDescriptor *matchDescriptor, StringRef MatcherName) {
+    auto K = ast_type_traits::ASTNodeKind::getFromNodeKind<
+        typename ast_matchers::internal::VariadicAllOfMatcher<ResultT>::Type>();
----------------
steveire wrote:
> aaron.ballman wrote:
> > Mildly not keen on the use of `auto` here. It's a factory function, so it kind of names the resulting type, but it also looks like the type will be `ast_matchers::internal::VariadicAllOfMatcher<ResultT>::Type` from the template argument, which is incorrect.
> There is no reason to assume that taking a template argument means that type is result.
> 
> The method is `getFrom` which decreases the ambiguity still further.
> 
> Spelling out the type doesn't add anything useful. This should be ok.
> There is no reason to assume that taking a template argument means that type is result.

Aside from all the other places that do exactly that (getAs<>, cast<>, dyn_cast<>, castAs<>, and so on). Generally, when we have a function named get that takes a template type argument, the result when seen in proximity to auto is the template type.

> Spelling out the type doesn't add anything useful. This should be ok.

I slept on this one and fall on the other side of it; using auto hides information that tripped up at least one person when reading the code, so don't use auto. It's not clear enough what the resulting type will be.


Repository:
  rC Clang

https://reviews.llvm.org/D54405