[WIP] Fix override checking for Java covariant array return types #24377
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tanishiking commented Nov 11, 2025
| && args1.length == 1 => | ||
| // Check if element types are Java-defined to detect Java arrays | ||
| val elem1Sym = args1.head.typeSymbol | ||
| val elem2Sym = arg2.typeSymbol |
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Ah, it doesn't work if the elemnt type is defined in Scala :/
We need to somehow check AppliedType(ArrayClass, args)s are JavaArray or not 🤔
This was referenced Nov 12, 2025
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Fixes #24074
When Java methods use covariant array return types (e.g.,
B[] getData()overridingA[] getData()), the compiler failed to recognize them as valid overrides because Scala sees those array invaliant.This PR adds special handling in
TypeComparerto treat Java arrays as covariant during override checking forAppliedType(Array, ...)whereArray.is(JavaDefined).Not very confident this is the clear solution for the issue, and some other tests would fail.