e9d85f49e6
Based on the discussion at https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/for.2C.20unexpected.20need.20for.20type.20ascription/near/269083574 The consensus seemed to be that "auto pure" is more confusing than its worth.
26 lines
838 B
Text
26 lines
838 B
Text
import Lean
|
|
|
|
open Lean
|
|
open Lean.Meta
|
|
|
|
def f (x : Type) := x
|
|
|
|
def tst : MetaM Unit := do
|
|
let m1 ← mkFreshExprMVar none
|
|
withLocalDeclD `x m1 fun x => do
|
|
trace[Meta.debug] "{x} : {← inferType x}"
|
|
trace[Meta.debug] "{m1} : {← inferType m1}"
|
|
let m2 ← mkFreshExprMVar (mkSort levelOne)
|
|
let t ← mkAppM ``f #[m2]
|
|
trace[Meta.debug] "{m2} : {← inferType m2}"
|
|
unless (← fullApproxDefEq <| isDefEq m1 t) do -- m1 := f m3 -- where `m3` has a smaller scope than `m2`
|
|
throwError "isDefEq failed"
|
|
trace[Meta.debug] "{m2} : {← inferType m2}"
|
|
trace[Meta.debug] "{m1} : {← inferType m1}"
|
|
let e ← mkForallFVars #[x] m2 -- `forall (x : f ?m2), ?m2`
|
|
trace[Meta.debug] "{e} : {← inferType e}"
|
|
return ()
|
|
|
|
set_option trace.Meta.isDefEq true
|
|
set_option trace.Meta.debug true
|
|
#eval tst
|