EqualityConstraints extension?
At the moment, writing an equality constraint in a type requires at least one of the GADTs or TypeFamilies extensions. However, each of these has other effects. Could we have an EqualityConstraints extension to permit equality constraints in types, but neither GADTs nor type families? Presumably this extension should imply MonoLocalBinds.
The GADTs extension could then become precisely the conjunction of GADTSyntax, EqualityConstraints and ExistentialQuantification.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.11 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
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| Blocking | |
| CC | |
| Operating system | |
| Architecture |