fix: #23261 Distinguish 0.0 and -0.0 in ConstantType match types #23265
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| @@ -401,7 +401,13 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling | |||
| compareErasedValueType | |||
| case ConstantType(v2) => | |||
| tp1 match { | |||
| case ConstantType(v1) => v1.value == v2.value && recur(v1.tpe, v2.tpe) | |||
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MEMO
I tried to modify the Constants.scala below to change the processing of the == method, but it didn't work.
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The line should use equals, which is already correct, see equalHashValue comment.
case ConstantType(v1) => v1.value.equals(v2.value) && recur(v1.tpe, v2.tpe)
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sorry, second look says
v1 == v2 && recur(v1.tpe, v2.tpe)
Do not unwrap Constant to underlying value, use equals on Constant.
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The internal tag in Constant is already checked for equality. Then recur(v1.tpe, v2.tpe) is not needed.
However, what about ClazzTag where Constant wraps a Type?
In general, the equals check is wrong. But if the underlying type is always some normalized class type, and it's comparing invariant Class[C], then the existing v1.value == v2.value is correct (and v1 == v2 is also correct).
tests/neg/i23261.scala
Outdated
| @@ -0,0 +1,7 @@ | |||
| @main def main(): Unit = | |||
| summon[0.0 =:= -0.0] | |||
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summon[0.0 =:= -0.0] // error
to annotate an expected error on that line
- Ensure match types distinguish between 0.0 and -0.0 in pattern matching. - This enables accurate reduction in match types involving Double constants. Close scala#23261
kijuky
changed the title
| @@ -401,7 +401,13 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling | |||
| compareErasedValueType | |||
| case ConstantType(v2) => | |||
| tp1 match { | |||
| case ConstantType(v1) => v1.value == v2.value && recur(v1.tpe, v2.tpe) | |||
There was a problem hiding this comment.
The internal tag in Constant is already checked for equality. Then recur(v1.tpe, v2.tpe) is not needed.
However, what about ClazzTag where Constant wraps a Type?
In general, the equals check is wrong. But if the underlying type is always some normalized class type, and it's comparing invariant Class[C], then the existing v1.value == v2.value is correct (and v1 == v2 is also correct).
Fixes #23261