reflect: add TypeFor

Fixes #60088 Change-Id: I7b43d329def22c2524501ba1d6bfc73becc823d1 GitHub-Last-Rev: becd714c4562da4a3280c3a56ebaf246e48e9f37 GitHub-Pull-Request: golang/go#61598 Reviewed-on: https://go-review.googlesource.com/c/go/+/513478 TryBot-Result: Gopher Robot <[email protected]> Run-TryBot: Ian Lance Taylor <[email protected]> Auto-Submit: Ian Lance Taylor <[email protected]> Reviewed-by: David Chase <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> Run-TryBot: Ian Lance Taylor <[email protected]>
cloudflare · Jul 31, 2023 · 42d2dfb · 42d2dfb
1 parent f024e39
commit 42d2dfb
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diff --git a/api/next/60088.txt b/api/next/60088.txt
@@ -0,0 +1 @@
+pkg reflect, func TypeFor[$0 interface{}]() Type #60088
diff --git a/src/reflect/type.go b/src/reflect/type.go
@@ -2911,3 +2911,8 @@ func addTypeBits(bv *bitVector, offset uintptr, t *abi.Type) {
  }
  }
 }
+
+// TypeFor returns the [Type] that represents the type argument T.
+func TypeFor[T any]() Type {
+ return TypeOf((*T)(nil)).Elem()
+}
diff --git a/src/reflect/type_test.go b/src/reflect/type_test.go
@@ -0,0 +1,35 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflect_test
+
+import (
+ "reflect"
+ "testing"
+)
+
+func TestTypeFor(t *testing.T) {
+ type (
+ mystring string
+ myiface interface{}
+ )
+
+ testcases := []struct {
+ wantFrom any
+ got reflect.Type
+ }{
+ {new(int), reflect.TypeFor[int]()},
+ {new(int64), reflect.TypeFor[int64]()},
+ {new(string), reflect.TypeFor[string]()},
+ {new(mystring), reflect.TypeFor[mystring]()},
+ {new(any), reflect.TypeFor[any]()},
+ {new(myiface), reflect.TypeFor[myiface]()},
+ }
+ for _, tc := range testcases {
+ want := reflect.ValueOf(tc.wantFrom).Elem().Type()
+ if want != tc.got {
+ t.Errorf("unexpected reflect.Type: got %v; want %v", tc.got, want)
+ }
+ }
+}