Version 2 (modified by simonpj, 19 months ago) (diff)


Type error messages

Ideas and suggestions for improving type error messages

Here's the wiki page for it.


Use Keyword = TypeErrorMessages to ensure that a ticket ends up on these lists.

Open Tickets:

Impredicativity bug: Church2 test gives a rather confusing error with the HEAD
Confusing type error message
Report out of date interface files robustly
Prettier error messages?
Improve type mismatch error messages
Compiler could warn about type variable shadowing, and hint about ScopedTypeVariables
Weird behavior with polymorphic function involving existential quantification and GADTs
Poor type error message when an argument is insufficently polymorphic
TypeInType error message regressions
Error says to fix incorrect return type
Confusing error message with multiparameter type classes.
Improving Type Error Messages
Error cascade with type applications
Non-local bug reporting around levity polymorphism
Error messages: suggest annotating with higher-rank kind
Cannot deduce constraint from itself with poly-kinded type family

Closed Tickets:

Misleading error message with forgotten "do"
Poor error message
When PolyKinds is on, suggested type signatures seem to require TypeInType