[PATCH] D119136: [clang] Implement Change scope of lambda trailing-return-type

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:7702
+  def err_lambda_used_before_capture: Error<
+    "captured variable %0 cannot appear before the end of the lambda's parameter list">;
   def note_lambda_variable_capture_fixit : Note<
----------------
aaron.ballman wrote:
> cor3ntin wrote:
> > aaron.ballman wrote:
> > > 
> > That doesn't work
> > 
> > ```
> > [a]<typename x = decltype(a)>(decltype(a) )
> >                       ^ nope            ^ double nope
> > ```
> It looks like this comment may have been missed.
Thank you for this! I think we should go with %select to name where it cannot be used. e.g., `cannot be used in a lambda %select{parameter list|template parameter list|whatever}1`


================
Comment at: clang/test/SemaCXX/lambda-capture-type-deduction.cpp:61
+  ();
+  [x]() requires is_same<const int &, decltype((x))> {}
+  ();
----------------
Can you also add test coverage for when the `requires` comes *before* the parens as in: `[x] requires(is_same<const int &, decltype((x))>)(){}();`?

I think you should also look at the grammar for lambda-expression to make sure we're not missing other coverage (use in attributes also appears to be untested).


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119136/new/

https://reviews.llvm.org/D119136