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varkor opened this issue Sep 15, 2020 · 2 comments · Fixed by #77758
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Suggest turbofish for uninferred const arguments #76737

varkor opened this issue Sep 15, 2020 · 2 comments · Fixed by #77758
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A-const-generics Area: const generics (parameters and arguments) A-diagnostics Area: Messages for errors, warnings, and lints A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` const-generics-bad-diagnostics An error is correctly emitted, but is confusing, for `min_const_generics`. D-terse Diagnostics: An error or lint that doesn't give enough information about the problem at hand. F-const_generics `#![feature(const_generics)]`

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@varkor
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varkor commented Sep 15, 2020

At the moment, we simply emit errors like:

error[E0282]: type annotations needed
  --> $DIR/method-chain.rs:21:33
   |
LL |     Foo.bar().bar().bar().bar().baz();
   |                                 ^^^
   |
   = note: cannot infer the value of the const parameter `N`

It would be good to suggest to the user how to fix this, like with uninferred type arguments.
@varkor varkor added A-diagnostics Area: Messages for errors, warnings, and lints A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` A-const-generics Area: const generics (parameters and arguments) F-const_generics `#![feature(const_generics)]` D-terse Diagnostics: An error or lint that doesn't give enough information about the problem at hand. const-generics-blocking const-generics-bad-diagnostics An error is correctly emitted, but is confusing, for `min_const_generics`. labels Sep 15, 2020
@varkor varkor mentioned this issue Sep 15, 2020
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@lcnr lcnr mentioned this issue Sep 23, 2020
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RalfJung added a commit to RalfJung/rust that referenced this issue Sep 26, 2020
@RalfJung
Rollup merge of rust-lang#77093 - lcnr:const-generics-infer-warning, …
04c4696 
…r=varkor

merge `need_type_info_err(_const)`

I hoped that this would automatically solve rust-lang#76737 but it doesn't quite seem like it

fixes rust-lang#77092

r? @varkor
RalfJung added a commit to RalfJung/rust that referenced this issue Sep 26, 2020
@RalfJung
Rollup merge of rust-lang#77093 - lcnr:const-generics-infer-warning, …
ac8169d 
…r=varkor

merge `need_type_info_err(_const)`

I hoped that this would automatically solve rust-lang#76737 but it doesn't quite seem like it

fixes rust-lang#77092

r? @varkor
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varkor commented Oct 9, 2020

Stu over on Zulip has picked this issue up.

@Stupremee Stupremee mentioned this issue Oct 9, 2020
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@bors bors closed this as completed in 9b2117d Nov 26, 2020
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A-const-generics Area: const generics (parameters and arguments) A-diagnostics Area: Messages for errors, warnings, and lints A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` const-generics-bad-diagnostics An error is correctly emitted, but is confusing, for `min_const_generics`. D-terse Diagnostics: An error or lint that doesn't give enough information about the problem at hand. F-const_generics `#![feature(const_generics)]`
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suggest turbofish syntax for uninferred const arguments Stupremee/rust
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