text/template, html/template: use reflect.TypeFor for known types

For #60088

Change-Id: Ibc3983ca5cfe396087ddfa96c43cfe32ca47129a
Reviewed-on: https://go-review.googlesource.com/c/go/+/514640
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>

src/html/template/content.go

@@ -128,8 +128,8 @@ func indirect(a any) any {
 }
 
 var (
-	errorType       = reflect.TypeOf((*error)(nil)).Elem()
-	fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+	errorType       = reflect.TypeFor[error]()
+	fmtStringerType = reflect.TypeFor[fmt.Stringer]()
 )
 
 // indirectToStringerOrError returns the value, after dereferencing as many times

src/html/template/exec_test.go

@@ -268,8 +268,8 @@ type execTest struct {
 // of the max int boundary.
 // We do it this way so the test doesn't depend on ints being 32 bits.
 var (
-	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeOf(0).Bits()-1)-1))
-	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeOf(0).Bits()-1)))
+	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeFor[int]().Bits()-1)-1))
+	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeFor[int]().Bits()-1)))
 )
 
 var execTests = []execTest{

src/html/template/js.go

@@ -124,7 +124,7 @@ var regexpPrecederKeywords = map[string]bool{
 	"void":       true,
 }
 
-var jsonMarshalType = reflect.TypeOf((*json.Marshaler)(nil)).Elem()
+var jsonMarshalType = reflect.TypeFor[json.Marshaler]()
 
 // indirectToJSONMarshaler returns the value, after dereferencing as many times
 // as necessary to reach the base type (or nil) or an implementation of json.Marshal.

src/text/template/exec.go

@@ -94,7 +94,7 @@ type missingValType struct{}
 
 var missingVal = reflect.ValueOf(missingValType{})
 
-var missingValReflectType = reflect.TypeOf(missingValType{})
+var missingValReflectType = reflect.TypeFor[missingValType]()
 
 func isMissing(v reflect.Value) bool {
 	return v.IsValid() && v.Type() == missingValReflectType
@@ -708,9 +708,9 @@ func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node,
 }
 
 var (
-	errorType        = reflect.TypeOf((*error)(nil)).Elem()
-	fmtStringerType  = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
-	reflectValueType = reflect.TypeOf((*reflect.Value)(nil)).Elem()
+	errorType        = reflect.TypeFor[error]()
+	fmtStringerType  = reflect.TypeFor[fmt.Stringer]()
+	reflectValueType = reflect.TypeFor[reflect.Value]()
 )
 
 // evalCall executes a function or method call. If it's a method, fun already has the receiver bound, so

src/text/template/exec_test.go

@@ -265,8 +265,8 @@ type execTest struct {
 // of the max int boundary.
 // We do it this way so the test doesn't depend on ints being 32 bits.
 var (
-	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeOf(0).Bits()-1)-1))
-	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeOf(0).Bits()-1)))
+	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeFor[int]().Bits()-1)-1))
+	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeFor[int]().Bits()-1)))
 )
 
 var execTests = []execTest{