internal/subtle: rename to internal/alias

This avoids an import conflict in code that needs to import
crypto/subtle as well.

CL 424194 does the same for the main repo.

Change-Id: Ic54cb62bbfdcf5c2cb6f15ac47075ee1c41981ad
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/424175
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>

internal/alias/alias.go

@@ -5,9 +5,8 @@
 //go:build !purego
 // +build !purego
 
-// Package subtle implements functions that are often useful in cryptographic
-// code but require careful thought to use correctly.
-package subtle // import "golang.org/x/crypto/internal/subtle"
+// Package alias implements memory aliasing tests.
+package alias
 
 import "unsafe"
 

internal/alias/alias_purego.go

@@ -5,9 +5,8 @@
 //go:build purego
 // +build purego
 
-// Package subtle implements functions that are often useful in cryptographic
-// code but require careful thought to use correctly.
-package subtle // import "golang.org/x/crypto/internal/subtle"
+// Package alias implements memory aliasing tests.
+package alias
 
 // This is the Google App Engine standard variant based on reflect
 // because the unsafe package and cgo are disallowed.

internal/alias/alias_test.go

@@ -2,13 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package subtle_test
+package alias
 
-import (
-	"testing"
-
-	"golang.org/x/crypto/internal/subtle"
-)
+import "testing"
 
 var a, b [100]byte
 
@@ -32,11 +28,11 @@ var aliasingTests = []struct {
 }
 
 func testAliasing(t *testing.T, i int, x, y []byte, anyOverlap, inexactOverlap bool) {
-	any := subtle.AnyOverlap(x, y)
+	any := AnyOverlap(x, y)
 	if any != anyOverlap {
 		t.Errorf("%d: wrong AnyOverlap result, expected %v, got %v", i, anyOverlap, any)
 	}
-	inexact := subtle.InexactOverlap(x, y)
+	inexact := InexactOverlap(x, y)
 	if inexact != inexactOverlap {
 		t.Errorf("%d: wrong InexactOverlap result, expected %v, got %v", i, inexactOverlap, any)
 	}