Fix widen types before checking an implicit view exists #18719
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The implementation here comes from porting from nsc. But I think things were done differently enough with its Global state, that make it not translate nicely here. So I'm paring it down to what I know works (at least for me): versions, settings, compilation unit. Not the tree/symbol/site stuff.
It's not possible to convert a method, such as a polymorphic method, such as `makeChurch`, into another type - we need to widen out the TermRef to discover the underlying PolyType which isn't a value type. Failing to do so will create a dummyTreeOfType, which will then be attempted to be applied, which eventually causes an assertion crash while building the tpd.TypeApply.
dwijnand
commented
Oct 19, 2023
| @@ -850,7 +850,7 @@ trait Implicits: | |||
| && !to.isError | |||
| && !ctx.isAfterTyper | |||
| && ctx.mode.is(Mode.ImplicitsEnabled) | |||
| && from.isValueType | |||
| && from.widen.isValueType | |||
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Counter-example:
given foo[A]: (Ctx => Int) = _ => 42
val works = get[Int](using summon[Ctx => Int])
val fails = get[Int]using the example from #16453 - with this change (or !imp.underlying.isInstanceOf[PolyType] in ignoredConvertibleImplicits) the suggestion of foo will be dropped, even though it's a correct suggestion.
odersky
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Oct 19, 2023
This was referenced Oct 20, 2023
odersky
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Oct 25, 2023
…singleton types This is an alternative fix for scala#18695, which already got fixed in a different way by scala#18719. This PR adds the actual tests, and leaves in the fix as a defensive measure in case the situation arises by some other means than the one foxed in scala#18719.
|
Tweaked in #18727. |
odersky
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Dec 17, 2023
Using issue #18650 as the reference (but issue #18999 is another option) building on the fix in PR #18719 (refined in PR #18727) as well as the fix in PR #18760, I'm trying to make a more root change here by making sure that message forcing only occurs with `hasErrors`/`errorsReported` is true, so as to avoid assertion errors crashing the compiler.
dwijnand
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Feb 21, 2024
Using issue scala#18650 as the reference (but issue scala#18999 is another option) building on the fix in PR scala#18719 (refined in PR scala#18727) as well as the fix in PR scala#18760, I'm trying to make a more root change here by making sure that message forcing only occurs with `hasErrors`/`errorsReported` is true, so as to avoid assertion errors crashing the compiler. (cherry picked from commit 10f2c10)
dwijnand
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Mar 5, 2024
Using issue scala#18650 as the reference (but issue scala#18999 is another option) building on the fix in PR scala#18719 (refined in PR scala#18727) as well as the fix in PR scala#18760, I'm trying to make a more root change here by making sure that message forcing only occurs with `hasErrors`/`errorsReported` is true, so as to avoid assertion errors crashing the compiler. (cherry picked from commit 10f2c10)
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Fixes #18650