GHC issueshttps://gitlab.haskell.org/ghc/ghc/-/issues2022-11-20T11:46:11Zhttps://gitlab.haskell.org/ghc/ghc/-/issues/14343bad pretty-printing of types with promoted data types2022-11-20T11:46:11Zlspitznerbad pretty-printing of types with promoted data types```
> :set -XDataKinds
> :set -XPolyKinds
> data Proxy k = Proxy
> _ :: Proxy '[ 'True ]
error:
Found hole: _ :: Proxy '['True]
> _ :: Proxy '['True]
error:
Invalid type signature: _ :: ...
Should be of form <variab...```
> :set -XDataKinds
> :set -XPolyKinds
> data Proxy k = Proxy
> _ :: Proxy '[ 'True ]
error:
Found hole: _ :: Proxy '['True]
> _ :: Proxy '['True]
error:
Invalid type signature: _ :: ...
Should be of form <variable> :: <type>
```
Alternatively, this could be attributed to the parser/lexer doing an insufficient job there.
<details><summary>Trac metadata</summary>
| Trac field | Value |
| ---------------------- | ------------ |
| Version | 8.2.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture | |
</details>
<!-- {"blocked_by":[],"summary":"bad pretty-printing of types with promoted data types","status":"New","operating_system":"","component":"Compiler","related":[],"milestone":"","resolution":"Unresolved","owner":{"tag":"Unowned"},"version":"8.2.1","keywords":[],"differentials":[],"test_case":"","architecture":"","cc":[""],"type":"Bug","description":"{{{\r\n> :set -XDataKinds\r\n> :set -XPolyKinds\r\n> data Proxy k = Proxy\r\n> _ :: Proxy '[ 'True ]\r\nerror:\r\n Found hole: _ :: Proxy '['True]\r\n> _ :: Proxy '['True]\r\nerror:\r\n Invalid type signature: _ :: ...\r\n Should be of form <variable> :: <type>\r\n}}}\r\n\r\nAlternatively, this could be attributed to the parser/lexer doing an insufficient job there.","type_of_failure":"OtherFailure","blocking":[]} -->8.6.1Andreas HerrmannAndreas Herrmann