Fix to lub: recompute if either operand can be widened

odersky · odersky · commit 6eece756db81 · 2014-01-19T22:11:17.000+01:00
diff --git a/src/dotty/tools/dotc/core/TypeComparer.scala b/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -645,7 +645,7 @@ class TypeComparer(initctx: Context) extends DotClass {
         else {
           val tp1w = tp1.widen
           val tp2w = tp2.widen
-          if ((tp1 ne tp1w) && (tp2 ne tp2w)) lub(tp1w, tp2w)
+          if ((tp1 ne tp1w) || (tp2 ne tp2w)) lub(tp1w, tp2w)
           else orType(tp1w, tp2w) // no need to check subtypes again
         }
       }

Original file line number	Diff line number	Diff line change
`@@ -645,7 +645,7 @@ class TypeComparer(initctx: Context) extends DotClass {`
`645`	`645`	`else {`
`646`	`646`	`val tp1w = tp1.widen`
`647`	`647`	`val tp2w = tp2.widen`
`648`		`- if ((tp1 ne tp1w) && (tp2 ne tp2w)) lub(tp1w, tp2w)`
	`648`	`+ if ((tp1 ne tp1w) \|\| (tp2 ne tp2w)) lub(tp1w, tp2w)`
`649`	`649`	`else orType(tp1w, tp2w) // no need to check subtypes again`
`650`	`650`	`}`
`651`	`651`	`}`