internal/core/adt: fix matchPattern

matchPattern did not handle the case where Feature f
was `AnyString`. It now does. This also means that
more places in the code should check for label != nil,
as it is now possible for it to be nil even if kind is string.

Issue #3060

Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I3a814b92b0d28dd8408a95beff329042938f7192
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1194051
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

cue/types_test.go

@@ -1910,6 +1910,7 @@ func TestElem(t *testing.T) {
 		value string
 		path  []string
 		want  string
+		skip  bool
 	}{{
 		value: `
 		a: [...int]
@@ -1941,10 +1942,13 @@ func TestElem(t *testing.T) {
 		`,
 		path: []string{"a", "foo", "b", ""},
 		want: "{\n\tc: \"foo\" + string\n\td: string\n}",
+		skip: true, // TODO(p3): Skip because this is just a reordering.
 	}}
 	for _, tc := range testCases {
 		runMatrix(t, "", func(t *testing.T, cfg *evalConfig) {
-			TODO_V3(t, cfg)
+			if tc.skip {
+				TODO_V3(t, cfg)
+			}
 
 			v := cfg.getValue(t, tc.value)
 			v.v.Finalize(v.ctx()) // TODO: do in instance.

internal/core/adt/constraints.go

@@ -121,9 +121,7 @@ func matchPattern(ctx *OpContext, pattern Value, f Feature) bool {
 	// avoid many bound checks), which we probably should. Especially when we
 	// allow list constraints, like [<10]: T.
 	var label Value
-	if int64(f.Index()) == MaxIndex {
-		f = 0
-	} else if f.IsString() {
+	if f.IsString() && int64(f.Index()) != MaxIndex {
 		label = f.ToValue(ctx)
 	}
 
@@ -144,8 +142,8 @@ func matchPatternValue(ctx *OpContext, pattern Value, f Feature, label Value) (r
 	}
 
 	k := IntKind
-	if label != nil {
-		k = label.Kind()
+	if f.IsString() {
+		k = StringKind
 	}
 	if !k.IsAnyOf(pattern.Kind()) {
 		return false
@@ -173,7 +171,6 @@ func matchPatternValue(ctx *OpContext, pattern Value, f Feature, label Value) (r
 		return true
 
 	case *BasicType:
-		k := label.Kind()
 		return x.K&k == k
 
 	case *BoundValue:
@@ -198,6 +195,9 @@ func matchPatternValue(ctx *OpContext, pattern Value, f Feature, label Value) (r
 		return err == nil && xi == yi
 
 	case *String:
+		if label == nil {
+			return false
+		}
 		y, ok := label.(*String)
 		return ok && x.Str == y.Str