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-rw-r--r--test/files/pos/t4881.scala31
1 files changed, 31 insertions, 0 deletions
diff --git a/test/files/pos/t4881.scala b/test/files/pos/t4881.scala
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+class Contra[-T]
+trait A
+trait B extends A
+trait C extends B
+
+// test improved variance inference: first try formals to see in which variance positions the type param appears;
+// only when that fails to determine variance, look at result type
+object Test {
+ def contraLBUB[a >: C <: A](): Contra[a] = null
+ def contraLB[a >: C](): Contra[a] = null
+
+{
+ val x = contraLBUB() //inferred Contra[C] instead of Contra[A]
+ val x1: Contra[A] = x
+}
+
+{
+ val x = contraLB() //inferred Contra[C] instead of Contra[Any]
+ val x1: Contra[Any] = x
+}
+
+{
+ val x = contraLBUB // make sure it does the same thing as its ()-less counterpart
+ val x1: Contra[A] = x
+}
+
+{
+ val x = contraLB
+ val x1: Contra[Any] = x
+}
+}