cmd/cue: get go: ignore anonymous enums

Fixes #1183

Change-Id: Ib97ca5f7923f8135a295196e6440886f024033dd
Signed-off-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/528035
Reviewed-by: Marcel van Lohuizen <mpvl@gmail.com>

Author: mpvl

cmd/cue/cmd/get_go.go

@@ -716,6 +716,9 @@ func (e *extractor) reportDecl(x *ast.GenDecl) (a []cueast.Decl) {
 				var exprs []cueast.Expr
 				var named []cueast.Decl
 				for _, v := range enums {
+					if v == "_" {
+						continue
+					}
 					label := cueast.NewString(v)
 					cueast.SetRelPos(label, cuetoken.Blank)
 

cmd/cue/cmd/testdata/script/get_go_anon.txt

@@ -0,0 +1,57 @@
+# Issue #1183
+
+# Run get go
+exec cue get go --local .
+cmp a_go_gen.cue a_go_gen.cue.golden
+
+-- a.go --
+package a
+
+type C int
+
+// define some typed constants
+const (
+	A C = iota
+	b
+	_
+	c
+)
+
+// define some untyped constants
+const (
+	D = iota
+	e
+	_
+	f
+)
+-- go.mod --
+module example.com/a
+
+go 1.16
+-- a_go_gen.cue.golden --
+// Code generated by cue get go. DO NOT EDIT.
+
+//cue:generate cue get go example.com/a
+
+package a
+
+#C: int // #enumC
+
+#enumC:
+	#A |
+	_#b |
+	_#c
+
+#values_C: {
+	A: #A
+	b: _#b
+	c: _#c
+}
+
+#A:  #C & 0
+_#b: #C & 1
+_#c: #C & 3
+
+#D:  0
+_#e: 1
+_#f: 3