Don't let caseLambda bindings accumulate in constraint

odersky · odersky · commit 39a07c45a1d2 · 2021-05-04T12:52:48.000+02:00
Remove them when a `matchCases` has finished.
diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -2831,7 +2831,9 @@ class TrackingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
       if (provablyEmpty(scrut))
         NoType
       else
-        recur(cases)
+        val savedConstraint = constraint
+        try recur(cases)
+        finally constraint = savedConstraint // caseLambda additions are dropped
     }
   }
 }

Original file line number	Diff line number	Diff line change
`@@ -2831,7 +2831,9 @@ class TrackingTypeComparer(initctx: Context) extends TypeComparer(initctx) {`
`2831`	`2831`	`if (provablyEmpty(scrut))`
`2832`	`2832`	`NoType`
`2833`	`2833`	`else`
`2834`		`- recur(cases)`
	`2834`	`+ val savedConstraint = constraint`
	`2835`	`+ try recur(cases)`
	`2836`	`+ finally constraint = savedConstraint // caseLambda additions are dropped`
`2835`	`2837`	`}`
`2836`	`2838`	`}`
`2837`	`2839`	`}`