Use any in place of interface{} (#7566)

Earlier this evening I tried to run the Go
[modernize](https://pkg.go.dev/golang.org/x/tools/gopls/internal/analysis/modernize)
analyzer on OPA. That didn't go as planned:

- https://github.com/golang/go/issues/73661
- https://github.com/golang/go/issues/73663

While we wait for that to be fixed, I figured an old-fashioned
search-and-replace across the repo may work for at least the
`interface{}` to `any` conversion. That should help make it easier
to see the other fixes as applied by the modernize tool once it has
had those issues resolved.

Signed-off-by: Anders Eknert <anders@styra.com>

util/compare.go

@@ -11,9 +11,9 @@ import (
 // Compare returns 0 if a equals b, -1 if a is less than b, and 1 if b is than a.
 //
 // For comparison between values of different types, the following ordering is used:
-// nil < bool < int, float64 < string < []interface{} < map[string]interface{}. Slices and maps
+// nil < bool < int, float64 < string < []any < map[string]any. Slices and maps
 // are compared recursively. If one slice or map is a subset of the other slice or map
 // it is considered "less than". Nil is always equal to nil.
-func Compare(a, b interface{}) int {
+func Compare(a, b any) int {
 	return v1.Compare(a, b)
 }

util/json.go

@@ -16,7 +16,7 @@ import (
 //
 // This function is intended to be used in place of the standard json.Marshal
 // function when json.Number is required.
-func UnmarshalJSON(bs []byte, x interface{}) error {
+func UnmarshalJSON(bs []byte, x any) error {
 	return v1.UnmarshalJSON(bs, x)
 }
 
@@ -32,7 +32,7 @@ func NewJSONDecoder(r io.Reader) *json.Decoder {
 //
 // If the data cannot be decoded, this function will panic. This function is for
 // test purposes.
-func MustUnmarshalJSON(bs []byte) interface{} {
+func MustUnmarshalJSON(bs []byte) any {
 	return v1.MustUnmarshalJSON(bs)
 }
 
@@ -40,7 +40,7 @@ func MustUnmarshalJSON(bs []byte) interface{} {
 //
 // If the data cannot be encoded, this function will panic. This function is for
 // test purposes.
-func MustMarshalJSON(x interface{}) []byte {
+func MustMarshalJSON(x any) []byte {
 	return v1.MustMarshalJSON(x)
 }
 
@@ -49,7 +49,7 @@ func MustMarshalJSON(x interface{}) []byte {
 // Thereby, it is converting its argument to the representation expected by
 // rego.Input and inmem's Write operations. Works with both references and
 // values.
-func RoundTrip(x *interface{}) error {
+func RoundTrip(x *any) error {
 	return v1.RoundTrip(x)
 }
 
@@ -58,11 +58,11 @@ func RoundTrip(x *interface{}) error {
 //
 // Used for preparing Go types (including pointers to structs) into values to be
 // put through util.RoundTrip().
-func Reference(x interface{}) *interface{} {
+func Reference(x any) *any {
 	return v1.Reference(x)
 }
 
 // Unmarshal decodes a YAML, JSON or JSON extension value into the specified type.
-func Unmarshal(bs []byte, v interface{}) error {
+func Unmarshal(bs []byte, v any) error {
 	return v1.Unmarshal(bs, v)
 }

util/test/benchmark.go

@@ -34,25 +34,25 @@ func ObjectIterationBenchmarkModule(n int) string {
 
 // GenerateLargeJSONBenchmarkData returns a map of 100 keys and 100.000 key/value
 // pairs.
-func GenerateLargeJSONBenchmarkData() map[string]interface{} {
+func GenerateLargeJSONBenchmarkData() map[string]any {
 	return v1.GenerateLargeJSONBenchmarkData()
 }
 
 // GenerateJSONBenchmarkData returns a map of `k` keys and `v` key/value pairs.
-func GenerateJSONBenchmarkData(k, v int) map[string]interface{} {
+func GenerateJSONBenchmarkData(k, v int) map[string]any {
 	return v1.GenerateJSONBenchmarkData(k, v)
 }
 
 // GenerateConcurrencyBenchmarkData returns a module and data; the module
 // checks some input parameters against that data in a simple API authz
 // scheme.
-func GenerateConcurrencyBenchmarkData() (string, map[string]interface{}) {
+func GenerateConcurrencyBenchmarkData() (string, map[string]any) {
 	return v1.GenerateConcurrencyBenchmarkData()
 }
 
 // GenerateVirtualDocsBenchmarkData generates a module and input; the
 // numTotalRules and numHitRules create as many rules in the module to
 // match/miss the returned input.
-func GenerateVirtualDocsBenchmarkData(numTotalRules, numHitRules int) (string, map[string]interface{}) {
+func GenerateVirtualDocsBenchmarkData(numTotalRules, numHitRules int) (string, map[string]any) {
 	return v1.GenerateVirtualDocsBenchmarkData(numTotalRules, numHitRules)
 }