8424ddbb3e
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).
31 lines
1 KiB
Text
31 lines
1 KiB
Text
-- set_option trace.Meta.FunInd true
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def myTest {α}
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(mmotive : (x : List α) → Sort v)
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(x : List α)
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(h_1 : (a : α) → (dc : List α) → x = a :: dc → mmotive (a :: dc))
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(h_2 : (x' : List α) → x = x' → mmotive x') : mmotive x :=
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match (generalizing := false) h : x with
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| a :: dc => h_1 a dc h
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| x' => h_2 x' h
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/--
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error: Failed to realize constant myTest.fun_cases:
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Cannot derive functional cases principle (please report this issue)
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failed to transform matcher, type error when constructing new pre-splitter motive:
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myTest.match_1 (fun x => motive x h_1 h_2) x
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failed with
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Application type mismatch: In the application
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motive x✝ h_1
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the argument
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h_1
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has type
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(a : α) → (dc : List α) → x = a :: dc → mmotive (a :: dc)
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but is expected to have type
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(a : α) → (dc : List α) → x✝ = a :: dc → mmotive (a :: dc)
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---
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error: unknown identifier 'myTest.fun_cases'
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-/
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#guard_msgs in
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def foo := @myTest.fun_cases
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