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…nd var This PR fixes #12768, where the new `do` elaborator produced a "declaration has free variables" kernel error when the bind continuation's result type was definitionally but not syntactically independent of the bound variable. The fix moves creation of the result type metavariable before `withLocalDecl`, so the unifier must reduce away the dependency. For example, given `def Quoted (x : Nat) := Nat`, the expression `do let val ← pure 3; withStuff val do return 3` would fail because `β` was assigned `Quoted val` rather than `Nat`.
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#13396) This PR fixes #12768, where the new `do` elaborator produced a "declaration has free variables" kernel error when the bind continuation's result type was definitionally but not syntactically independent of the bound variable. The fix moves creation of the result type metavariable before `withLocalDecl`, so the unifier must reduce away the dependency. For example, given `def Quoted (x : Nat) := Nat`, the expression `do let val ← pure 3; withStuff val do return 3` would fail because `β` was assigned `Quoted val` rather than `Nat`.
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This PR fixes #12768, where the new
doelaborator produced a "declaration has free variables" kernel error when the bind continuation's result type was definitionally but not syntactically independent of the bound variable. The fix moves creation of the result type metavariable beforewithLocalDecl, so the unifier must reduce away the dependency.For example, given
def Quoted (x : Nat) := Nat, the expressiondo let val ← pure 3; withStuff val do return 3would fail becauseβwas assignedQuoted valrather thanNat.