fixes #21887; Type conversion on overloaded enum field does not always call (#21908)

* fixes #21887; Type conversion on overloaded enum field does not always call

* remove comments

* add a test case

* restrict it to enums

compiler/semexprs.nim

@@ -349,6 +349,9 @@ proc semConv(c: PContext, n: PNode; expectedType: PType = nil): PNode =
       targetType.skipTypes(abstractPtrs).kind == tyObject:
     localError(c.config, n.info, "object construction uses ':', not '='")
   var op = semExprWithType(c, n[1])
+  if op.kind == nkClosedSymChoice and op.len > 0 and
+      op[0].sym.kind == skEnumField: # resolves overloadedable enums
+    op = ambiguousSymChoice(c, n, op)
   if targetType.kind != tyGenericParam and targetType.isMetaType:
     let final = inferWithMetatype(c, targetType, op, true)
     result.add final

tests/enum/toverloadable_enums.nim

@@ -118,3 +118,11 @@ block: # test with macros/templates
   doAssert isOneMS(e2)
   doAssert isOneT(e1)
   doAssert isOneT(e2)
+
+block: # bug #21908
+  type
+    EnumA = enum A = 300, B
+    EnumB = enum A = 10
+    EnumC = enum C
+
+  doAssert typeof(EnumC(A)) is EnumC