Don't let caseLambda bindings accumulate in constraint

odersky · odersky · commit 842bd7a9303f · 2021-05-04T21:31:34.000+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
@@ -2879,7 +2879,9 @@ 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
`@@ -2879,7 +2879,9 @@ class TrackingTypeComparer(initctx: Context) extends TypeComparer(initctx) {`
`2879`	`2879`	`if (provablyEmpty(scrut))`
`2880`	`2880`	`NoType`
`2881`	`2881`	`else`
`2882`		`- recur(cases)`
	`2882`	`+ val savedConstraint = constraint`
	`2883`	`+ try recur(cases)`
	`2884`	`+ finally constraint = savedConstraint // caseLambda additions are dropped`
`2883`	`2885`	`}`
`2884`	`2886`	`}`
`2885`	`2887`	`}`