Fix scala#11973: Bail out on EnumValues

dotty-staging · May 28, 2021 · 78f9951 · 78f9951
1 parent e48a268
commit 78f9951
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -2475,9 +2475,12 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
   def provablyDisjoint(tp1: Type, tp2: Type)(using Context): Boolean = trace(i"provable disjoint $tp1, $tp2", matchTypes) {
     // println(s"provablyDisjoint(${tp1.show}, ${tp2.show})")
 
-    def isEnumValueOrModule(ref: TermRef): Boolean =
+    def isEnumValue(ref: TermRef): Boolean =
       val sym = ref.termSymbol
-      sym.isAllOf(EnumCase, butNot=JavaDefined) || sym.is(Module)
+      sym.isAllOf(EnumCase, butNot=JavaDefined)
+
+    def isEnumValueOrModule(ref: TermRef): Boolean =
+      isEnumValue(ref) || ref.termSymbol.is(Module)
 
     /** Can we enumerate all instantiations of this type? */
     def isClosedSum(tp: Symbol): Boolean =
@@ -2586,6 +2589,10 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
         provablyDisjoint(tp1, gadtBounds(tp2.symbol).hi) || provablyDisjoint(tp1, tp2.superType)
       case (tp1: TermRef, tp2: TermRef) if isEnumValueOrModule(tp1) && isEnumValueOrModule(tp2) =>
         tp1.termSymbol != tp2.termSymbol
+      case (tp1: TermRef, _) if isEnumValue(tp1) =>
+        false
+      case (_, tp2: TermRef) if isEnumValue(tp2) =>
+        false
       case (tp1: Type, tp2: Type) if defn.isTupleType(tp1) =>
         provablyDisjoint(tp1.toNestedPairs, tp2)
       case (tp1: Type, tp2: Type) if defn.isTupleType(tp2) =>

diff --git a/tests/pos/11973.scala b/tests/pos/11973.scala
@@ -0,0 +1,9 @@
+enum E:
+  case C
+
+trait T
+
+def f(x: E | T): Unit = x match {
+  case e: E => ()
+  case t: T => ()
+}