enable vet.

.github/workflows/go.yml

@@ -25,6 +25,9 @@ jobs:
       run: |
         go get -v -t -d ./...
 
+    - name: Vet
+      run: go vet -stdmethods=false ./...
+
     - name: Build
       run: go build -v ./...
 

utils/sys.go

@@ -13,15 +13,18 @@ type multiReadSeeker struct {
 	multiReader io.Reader
 }
 
+func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
+	return unsafe.Pointer(uintptr(p) + x)
+}
+
 func IsChanClosed(ch interface{}) bool {
 	if reflect.TypeOf(ch).Kind() != reflect.Chan {
 		panic("object is not a channel.")
 	}
-	ptr := *(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&ch)) + unsafe.Sizeof(uint(0))))
+	return *(*uint32)(
-	ptr += unsafe.Sizeof(uint(0)) * 2
+		add(*(*unsafe.Pointer)(add(unsafe.Pointer(&ch), unsafe.Sizeof(uintptr(0)))),
-	ptr += unsafe.Sizeof(uintptr(0))
+			unsafe.Sizeof(uint(0))*2+unsafe.Sizeof(uintptr(0))+unsafe.Sizeof(uint16(0))),
-	ptr += unsafe.Sizeof(uint16(0))
+	) > 0
-	return *(*uint32)(unsafe.Pointer(ptr)) > 0
 }
 
 func ComputeMd5AndLength(r io.Reader) ([]byte, int64) {