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

[Stephen Kelly via Phabricator via cfe-commits]

steveire added inline comments.


================
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>();
----------------
aaron.ballman wrote:
> 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.
I put this in the category of requiring 

    SomeType ST = SomeType::create();

instead of 

    auto ST = SomeType::create();

`ast_type_traits::ASTNodeKind` is already on that line and you want to see it again.



Repository:
  rC Clang

https://reviews.llvm.org/D54405