Fix #2152: Instantiate dependent result type parameters #2209
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I can confirm that this fixes the issue I described (in reduced form) in #2152. |
smarter
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Apr 11, 2017
scala#2152 shows that dependent result type parameters can end up in the types of terms, so we have to eliminate them. If we don't we get orphan parameters in pickling. Fix method name and comment
The original fix made run/hmap-covariant fail because a type variable representing a dependent result parameter was instantiated. Trying something else now.
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@propensive Can you please check whether the latest commit also solves the original issue you were having? Unfortunately my original fix broke something else. |
smarter
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May 21, 2020
`TypeOps#simplify` is supposed to produce a type `=:=` the original type, but it replaced type variables created using `newTypeVar` by one of their bound, this is wrong since that type variable might get instantiated to a different type later. This simplification was added in scala#2209 to prevent a pickling crash in tests/pos/i2152.scala but does not appear to be needed anymore: an uninstantiated type variable being preserved after typer is always wrong, so the underlying bug must have been fixed since then.
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#2152 shows that dependent result type parameters can end up in
the types of terms, so we have to eliminate them. If we don't we
get orphan parameters in pickling.
Based on #2128. Only one commit is new.