cue: tweak cue.Value.Decode with Go std changes

reflect.Ptr was replaced by reflect.Pointer some time ago.

Overflow* methods are now delared on types, removing the need
for calls to reflect.Zero to create a throwaway value.

While here, take gopls's suggestion to use a range-over-int.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I86288aaf9abccd0a82be54dc28b1cc67549ce7d9
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1209028
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Roger Peppe <[email protected]>

Author: mvdan

Diff for: cue/decode.go

@@ -102,7 +102,7 @@ func (d *decoder) decode(x reflect.Value, v Value, isPtr bool) {
 	}
 
 	switch x.Kind() {
-	case reflect.Ptr, reflect.Map, reflect.Slice, reflect.Interface:
+	case reflect.Pointer, reflect.Map, reflect.Slice, reflect.Interface:
 		// nullable types
 		if v.IsNull() || !v.IsConcrete() {
 			d.clear(x)
@@ -146,7 +146,7 @@ func (d *decoder) decode(x reflect.Value, v Value, isPtr bool) {
 	}
 
 	switch kind {
-	case reflect.Ptr:
+	case reflect.Pointer:
 		d.decode(x.Elem(), v, true)
 
 	case reflect.Bool:
@@ -368,7 +368,7 @@ func (d *decoder) convertMap(x reflect.Value, v Value) {
 			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 				n, err := strconv.ParseInt(key, 10, 64)
 				d.addErr(err)
-				if reflect.Zero(kt).OverflowInt(n) {
+				if kt.OverflowInt(n) {
 					d.addErr(errors.Newf(v.Pos(), "key integer %d overflows %s", n, kt))
 					break
 				}
@@ -377,7 +377,7 @@ func (d *decoder) convertMap(x reflect.Value, v Value) {
 			case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 				n, err := strconv.ParseUint(key, 10, 64)
 				d.addErr(err)
-				if reflect.Zero(kt).OverflowUint(n) {
+				if kt.OverflowUint(n) {
 					d.addErr(errors.Newf(v.Pos(), "key integer %d overflows %s", n, kt))
 					break
 				}
@@ -433,7 +433,7 @@ func (d *decoder) convertStruct(x reflect.Value, v Value) {
 		// Figure out field corresponding to key.
 		subv := x
 		for _, i := range f.index {
-			if subv.Kind() == reflect.Ptr {
+			if subv.Kind() == reflect.Pointer {
 				if subv.IsNil() {
 					// If a struct embeds a pointer to an unexported type,
 					// it is not possible to set a newly allocated value
@@ -537,12 +537,12 @@ func typeFields(t reflect.Type) structFields {
 			visited[f.typ] = true
 
 			// Scan f.typ for fields to include.
-			for i := 0; i < f.typ.NumField(); i++ {
+			for i := range f.typ.NumField() {
 				sf := f.typ.Field(i)
 				isUnexported := sf.PkgPath != ""
 				if sf.Anonymous {
 					t := sf.Type
-					if t.Kind() == reflect.Ptr {
+					if t.Kind() == reflect.Pointer {
 						t = t.Elem()
 					}
 					if isUnexported && t.Kind() != reflect.Struct {
@@ -568,7 +568,7 @@ func typeFields(t reflect.Type) structFields {
 				index[len(f.index)] = i
 
 				ft := sf.Type
-				if ft.Name() == "" && ft.Kind() == reflect.Ptr {
+				if ft.Name() == "" && ft.Kind() == reflect.Pointer {
 					// Follow pointer.
 					ft = ft.Elem()
 				}
@@ -883,7 +883,7 @@ func indirect(v reflect.Value, decodingNull bool) (json.Unmarshaler, encoding.Te
 	// If v is a named type and is addressable,
 	// start with its address, so that if the type has pointer methods,
 	// we find them.
-	if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
+	if v.Kind() != reflect.Pointer && v.Type().Name() != "" && v.CanAddr() {
 		haveAddr = true
 		v = v.Addr()
 	}
@@ -892,14 +892,14 @@ func indirect(v reflect.Value, decodingNull bool) (json.Unmarshaler, encoding.Te
 		// usefully addressable.
 		if v.Kind() == reflect.Interface && !v.IsNil() {
 			e := v.Elem()
-			if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
+			if e.Kind() == reflect.Pointer && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Pointer) {
 				haveAddr = false
 				v = e
 				continue
 			}
 		}
 
-		if v.Kind() != reflect.Ptr {
+		if v.Kind() != reflect.Pointer {
 			break
 		}