Allow enum unions

generator.go

@@ -661,14 +661,28 @@ func (g *generator) genInterfaceField(v cue.Value) (*typeRef, error) {
 		func(v cue.Value) bool { return targetsKind(cue.Dereference(v), TypeEnum) },
 	) {
 		op, args := v.Expr()
-		if op != cue.OrOp {
+		if op == cue.AndOp {
 			return g.genEnumReference(v)
 		}
+
+		// Check if has defaults
 		for _, a := range args {
 			if a.IncompleteKind() == cue.TopKind {
 				return g.genEnumReference(v)
 			}
 		}
+
+		// Check if it is a union
+		isUnion := true
+		for _, a := range args {
+			if a.Kind() != a.IncompleteKind() {
+				isUnion = false
+			}
+		}
+
+		if isUnion {
+			return g.genEnumReference(v)
+		}
 	}
 
 	// One path for when there's a ref to a cuetsy node, and a separate one otherwise

testdata/imports/compose_enums.txtar

@@ -20,10 +20,12 @@ Compose: {
     localnumover: LocalEnumNumericD & (*2 | _)
     impstr: dep.DepEnum & (*"bar" | _)
     impstrd: dep.DepEnumD
-    impstrover: dep.DepEnumD & (*"bar" | _)
+    impstrover: dep.DepEnumD | *"bar"
     impnum: dep.DepEnumNumeric & (*3 | _)
     impnumd: dep.DepEnumNumericD
-    impnumover: dep.DepEnumNumericD & (*3 | _)
+    impnumover: dep.DepEnumNumericD | *3
+    union: (dep.DepEnumNumericD & 2) | (dep.DepEnumNumericD & 3)
+    unionStrings: (LocalEnum & "bar") | (LocalEnum & "foo") | (LocalEnum & "baz")
 } @cuetsy(kind="interface")
 
 -- dep/file.cue --
@@ -77,15 +79,17 @@ export interface Compose {
   localstr: LocalEnum;
   localstrd: LocalEnumD;
   localstrover: LocalEnumD;
+  union: dep.DepEnumNumericD;
+  unionStrings: LocalEnum;
 }
 
 export const defaultCompose: Partial<Compose> = {
   impnum: dep.DepEnumNumeric.Three,
   impnumd: dep.DepEnumNumericD.One,
-  impnumover: dep.DepEnumNumericD.Three,
+  impnumover: 3,
   impstr: dep.DepEnum.Bar,
   impstrd: dep.DepEnumD.Foo,
-  impstrover: dep.DepEnumD.Bar,
+  impstrover: 'bar',
   localnum: LocalEnumNumeric.Two,
   localnumd: LocalEnumNumericD.One,
   localnumover: LocalEnumNumericD.Two,