Allow cold values in static methods using parametricity

Closes scala#14460 Allow cold arguments to be passed if the parameter is `!Matchable` and the method is global static.
Xavientois · Mar 22, 2022 · d719739 · d719739
1 parent e54a934
commit d719739
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Showing 6 changed files with 12 additions and 68 deletions.
diff --git a/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala b/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
@@ -1120,7 +1120,14 @@ object Semantic {
 
       case Call(ref, argss) =>
         // check args
-        val (errors, args) = evalArgs(argss.flatten, thisV, klass)
+        val (argErrors, args) = evalArgs(argss.flatten, thisV, klass)
+        // Allow cold args for static methods with non-matchable params
+        val methodType = ref.symbol.info.stripPoly
+        val allMatchable = methodType.paramInfoss.flatten.forall { (info) => info <:< defn.MatchableType }
+        val isStatic = ref.symbol.isStatic
+        val errors = if isStatic && allMatchable then
+          argErrors.filterNot(e => e.isInstanceOf[UnsafePromotion])
+        else argErrors
 
         ref match
         case Select(supert: Super, _) =>

diff --git a/tests/init/neg/enum-desugared.check b/tests/init/neg/enum-desugared.check
diff --git a/tests/init/neg/enum-desugared.scala b/tests/init/neg/enum-desugared.scala
diff --git a/tests/init/neg/enum.check b/tests/init/neg/enum.check
diff --git a/tests/init/neg/enum.scala b/tests/init/neg/enum.scala
diff --git a/tests/init/pos/inner-enum.scala b/tests/init/pos/inner-enum.scala
@@ -0,0 +1,4 @@
+class Outer:
+    enum MyEnum {
+        case Case
+    }