Error messages

There are many different error messages Disco can generate when something is wrong. Each page linked below gives more explanation and background to help you understand a particular error message.

The error messages in Disco are currently undergoing major improvements. If you have a suggestion on how a particular error message could be improved, please record it at https://github.com/disco-lang/disco/issues !

• There is nothing named x
• The name x is ambiguous
• The definition of x must have an accompanying type signature
• The expression e must have both a blah type and also…
• Empty case expressions are not allowed
• Value did not match any of the branches in a case expression
• Pattern p contains duplicate variable x
• The pattern p is supposed to have type T, but instead…
• Duplicate type signature for x
• Duplicate definition for x
• Duplicate definition for type T
• Cyclic type definition for T
• Number of arguments does not match
• The type T is not searchable
• There is no built-in or user-defined type named X
• Wildcards are not allowed in expressions
• Not enough/too many arguments for the type T
• Unknown type variable
• Recursive occurrences of T may only have type variables as arguments
• The shape of two types does not match
• Typechecking failed
• Values of type T cannot be…
• Type variable x represents any type, so we cannot assume…