Allow discarding "Discarded non-Unit" warnings with : Unit
#21927
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| else typed(tree.expr, underlyingTreeTpe.tpe.widenSkolem) | ||
| else | ||
| if underlyingTreeTpe.tpe.isRef(defn.UnitClass) then | ||
| untpd.unsplice(tree.expr).putAttachment(AscribedToUnit, ()) |
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untpd.unsplice is needed to ignore parentheses (so that (1 + 1): Unit also silents the warning, not only 1 + 1: Unit).
| @@ -10,6 +10,6 @@ object Test: | |||
| object Test2: | |||
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| if true then | |||
| 1 | |||
| () | |||
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Avoids the "non-Unit" warning, that is not directly related to this test.
| @@ -4,4 +4,4 @@ import annotation.experimental | |||
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| @experimental class Foo | |||
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| def test: Unit = new Foo // error: class Foo is marked @experimental ... | |||
| def test = (new Foo): Unit // error: class Foo is marked @experimental ... | |||
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Avoids the "non-Unit" warning, that is not directly related to this test.
| @@ -3377,7 +3383,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer | |||
| else if (ctx.mode.is(Mode.Pattern)) | |||
| typedUnApply(cpy.Apply(tree)(op, l :: r :: Nil), pt) | |||
| else { | |||
| val app = typedApply(desugar.binop(l, op, r), pt) | |||
| val app = typedApply(desugar.binop(l, op, r).withAttachmentsFrom(tree), pt) | |||
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Needed to add withAttachmentsFrom(tree) here so that we don't throw away attachments when desugaring binary operations.
mbovel
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Co-Authored-By: nmc.borst <[email protected]> Co-Authored-By: Jędrzej Rochala <[email protected]>
| @@ -3173,7 +3173,7 @@ class InlinedAnonClassWarning()(using Context) | |||
| class ValueDiscarding(tp: Type)(using Context) | |||
| extends Message(ValueDiscardingID): | |||
| def kind = MessageKind.PotentialIssue | |||
| def msg(using Context) = i"discarded non-Unit value of type $tp" | |||
| def msg(using Context) = i"discarded non-Unit value of type ${tp.widen}. Add `: Unit` to discard silently." | |||
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Let's create actionable diagnostics in the next spree for both diagnostics
Mmh, yeah, I thought two pairs of core-contributor eyes were enough, but it might indeed be even better to get an independent review. @dwijnand woud you have time to have a look? |
mbovel
removed
the
fasttrack
Continuation of the work done by @nmcb and @rochala during the Oct 20th spree.
This PR adds support for discarding "non-Unit" expressions by explicitly casting them to
Unit:Closes #21557.