lean4-htt/tests/lean/run/mergeSort.lean
Joachim Breitner 8424ddbb3e
feat: prettier expected type mismatch error message (#9099)
This PR improves the “expected type mismatch” error message by omitting
the type's types when they are defeq, and putting them into separate
lines when not.

I found it rather tediuos to parse the error message when the expected
type is long, because I had to find the `:` in the middle of a large
expression somewhere. Also, when both are of sort `Prop` or `Type` it
doesn't add much value to print the sort (and it’s only one hover away
anyways).
2025-07-01 07:50:53 +00:00

60 lines
1.9 KiB
Text

open List MergeSort Internal
-- If we omit the comparator, it is filled by the autoparam `fun a b => a ≤ b`
example : mergeSort [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5] = [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9] :=
by native_decide
example : mergeSort [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5] (· ≤ ·) = [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9] :=
by native_decide
example : mergeSort [3, 100 + 1, 4, 100 + 1, 5, 100 + 9, 2, 10 + 6, 5, 10 + 3, 5] (fun x y => x/10 ≤ y/10) = [3, 4, 5, 2, 5, 5, 16, 13, 101, 101, 109] :=
by native_decide
example : mergeSortTR [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5] = [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9] :=
by native_decide
example : mergeSortTR [3, 100 + 1, 4, 100 + 1, 5, 100 + 9, 2, 10 + 6, 5, 10 + 3, 5] (fun x y => x/10 ≤ y/10) = [3, 4, 5, 2, 5, 5, 16, 13, 101, 101, 109] :=
by native_decide
example : mergeSortTR₂ [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5] = [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9] :=
by native_decide
example : mergeSortTR₂ [3, 100 + 1, 4, 100 + 1, 5, 100 + 9, 2, 10 + 6, 5, 10 + 3, 5] (fun x y => x/10 ≤ y/10) = [3, 4, 5, 2, 5, 5, 16, 13, 101, 101, 109] :=
by native_decide
/-!
# Behaviour of mergeSort when the comparator is not provided, but typeclasses are missing.
-/
inductive NoLE
| mk : NoLE
/--
error: could not synthesize default value for parameter 'le' using tactics
---
error: failed to synthesize
LE NoLE
Hint: Additional diagnostic information may be available using the `set_option diagnostics true` command.
-/
#guard_msgs in
example : mergeSort [NoLE.mk] = [NoLE.mk] := sorry
inductive UndecidableLE
| mk : UndecidableLE
instance : LE UndecidableLE where
le := fun _ _ => true
/--
error: could not synthesize default value for parameter 'le' using tactics
---
error: type mismatch
a ≤ b
has type
Prop
but is expected to have type
Bool
-/
#guard_msgs in
example : mergeSort [UndecidableLE.mk] = [UndecidableLE.mk] := sorry