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Fix MatchError in wildcardArgOK for mixed wildcard/concrete type args #25001

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Fix MatchError in wildcardArgOK for mixed wildcard/concrete type args #25001

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1 change: 1 addition & 0 deletions compiler/src/dotty/tools/dotc/typer/Applications.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -900,6 +900,7 @@ trait Applications extends Compatibility {
if tycon1 =:= tycon2 && args1.length == args2.length =>
args1.lazyZip(args2).forall {
case (TypeBounds(_, hi), formal) => hi relaxed_<:< formal
case (arg, formal) => arg =:= formal
}
case _ => false
case _ => false
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9 changes: 8 additions & 1 deletion tests/run/overload_repeated/A_1.java
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Expand Up @@ -27,6 +27,12 @@ class A_1 {
public static <T> int foo9(Class<? extends T> a) { return 1; } // (a)
public static <T extends Number> int foo9(Class<T> a, int... ints) { return 2; } // (b)

// https://github.com/scala/scala3/issues/25000
// Mixed wildcard/concrete type args - tests that wildcardArgOK handles
// non-TypeBounds args correctly
public static <V> int foo10(java.util.Map<String, ? extends V> a) { return 1; }
public static <V> int foo10(java.util.Map<String, V> a, int... ints) { return 2; }

public static boolean check() {
// Java prefers non-varargs to varargs:
// https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.12.2
Expand All @@ -39,6 +45,7 @@ public static boolean check() {
foo6(Object.class) == 1 &&
foo7(Integer.class) == 1 &&
foo8(Integer.class) == 1 &&
foo9(Integer.class) == 1;
foo9(Integer.class) == 1 &&
foo10(new java.util.HashMap<String, Object>()) == 1;
}
}
9 changes: 9 additions & 0 deletions tests/run/overload_repeated/B_2.scala
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Expand Up @@ -29,6 +29,12 @@ object Test {
def bar9[T](a: Class[? <: T]): Int = 1 // (a)
def bar9[T <: Number](a: Class[T], ints: Int*): Int = 2 // (b)

// Mixed wildcard/concrete type args - tests that wildcardArgOK handles
// non-TypeBounds args correctly, using java.util.Map which is invariant
// see: https://github.com/scala/scala3/issues/25000
def bar10[V](a: java.util.Map[String, ? <: V]): Int = 1
def bar10[V](a: java.util.Map[String, V], ints: Int*): Int = 2

def main(args: Array[String]): Unit = {
// In Java, varargs are always less specific than non-varargs (see
// https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.12.2),
Expand All @@ -43,6 +49,8 @@ object Test {
assert(A_1.foo7(classOf[Integer]) == 1) // Same as in Java and Scala 2
assert(A_1.foo8(classOf[Integer]) == 1) // Same as in Java and Scala 2
// assert(A_1.foo9(classOf[Integer]) == 1) // Works in Java, ambiguous in Scala 2 and 3
val javaMap: java.util.Map[String, ? <: Object] = new java.util.HashMap()
assert(A_1.foo10(javaMap) == 1) // Same as in Java

// Same with Scala varargs:
// assert(bar1("") == 1) // Works in Java, ambiguous in Scala 2 and Dotty
Expand All @@ -54,5 +62,6 @@ object Test {
assert(bar7(classOf[Integer]) == 1) // same in Scala2
assert(bar8(classOf[Integer]) == 1) // same in Scala2
// assert(bar9(classOf[Integer]) == 1) Works in Java, ambiguous in Scala 2 and 3
assert(bar10(javaMap) == 1)
}
}
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