• Roland Senn's avatar
    Fix #14628: Panic (No skolem Info) in GHCi · 82f9be8c
    Roland Senn authored
    This patch implements the [sugggestion from Simon (PJ)](ghc/ghc#14628 (comment 146559)):
    - Make `TcErrors.getSkolemInfo` return a `SkolemInfo` rather than an `Implication`.
    - If `getSkolemInfo` gets `RuntimeUnk`s, just return a new data constructor in `SkolemInfo`, called `RuntimeUnkSkol`.
    - In `TcErrors.pprSkols` print something sensible for a `RuntimeUnkSkol`.
    
    The `getSkolemInfo` function paniced while formating suggestions to add type annotations (subfunction `suggestAddSig`)
    to a *"Couldn't match type ‘x’ with ‘y’"* error message.
    The `getSkolemInfo` function didn't find any Implication value and paniced.
    With this patch the `getSkolemInfo` function does no longer panic, if it finds `RuntimeUnkSkol`s.
    
    As the panic occured while processing an error message, we don't need to implement any new error message!
    82f9be8c
TcErrors.hs 123 KB