[PATCH] D116352: [CodeCompletion] Signature help for template argument lists

[Sam McCall via Phabricator via cfe-commits]

sammccall added inline comments.


================
Comment at: clang/lib/Sema/SemaCodeComplete.cpp:3785
+  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(TD))
+    return FTD->getTemplatedDecl()->getType().getAsString(Policy);
+  if (isa<TypeAliasTemplateDecl>(TD))
----------------
kadircet wrote:
> the rendering looks a little bit surprising to me `foo<arg1,arg2> -> bool (float)` we might consider printing parameters first, e.g. `foo<arg1,arg2>(float) -> bool`. i think this also looks more natural for the following signature help on function parameters.
Yeah. There are a few things going on here I wasn't sure how to square:

1) the "arrow" rendering is clangd-specific, and it reorders chunks by kind (moving the ResultType chunk to the end). So if we want a specific rendering in clangd we need to be able to infer it from the chunk sequence
2) the chunk sequence should make sense when rendered as text more directly. I think the current version fails this test: `bool(float) foo<arg1, arg2>`.
3) the rendering you suggest requires us to reverse the order of bool and float somehow, ideally without some fragile coupling/assumptions in clangd

I think the "natural" chunk sequence is `bool` `foo<` `arg1` `,` `arg2` `>` `(float)`. The `bool` chunk is definitely ResultType.

If we make `(float)` also ResultType, we know have two RT chunks we have to stick in the signature in the right place. So maybe it's best to make it `CK_Text` or `CK_Informative`. I'll give this a spin...


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D116352/new/

https://reviews.llvm.org/D116352