gocritic (1/2) (#3836)

Add gocritic as a linter

    The linting is not complete, but should i complete in this PR or in a following.

    23 files have been touched so it may be better to do in a following PR


Commits:

* Add gocritic to linting

- Added gocritic to linting

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* gocritic

* pr comments

* remove switch in cmdBatch

crypto/ed25519/ed25519.go

@@ -54,7 +54,7 @@ func (privKey PrivKeyEd25519) Bytes() []byte {
 // incorrect signature.
 func (privKey PrivKeyEd25519) Sign(msg []byte) ([]byte, error) {
 	signatureBytes := ed25519.Sign(privKey[:], msg)
-	return signatureBytes[:], nil
+	return signatureBytes, nil
 }
 
 // PubKey gets the corresponding public key from the private key.
@@ -100,7 +100,7 @@ func GenPrivKey() PrivKeyEd25519 {
 // genPrivKey generates a new ed25519 private key using the provided reader.
 func genPrivKey(rand io.Reader) PrivKeyEd25519 {
 	seed := make([]byte, 32)
-	_, err := io.ReadFull(rand, seed[:])
+	_, err := io.ReadFull(rand, seed)
 	if err != nil {
 		panic(err)
 	}

crypto/internal/benchmarking/bench.go

@@ -24,10 +24,10 @@ func (zeroReader) Read(buf []byte) (int, error) {
 
 // BenchmarkKeyGeneration benchmarks the given key generation algorithm using
 // a dummy reader.
-func BenchmarkKeyGeneration(b *testing.B, GenerateKey func(reader io.Reader) crypto.PrivKey) {
+func BenchmarkKeyGeneration(b *testing.B, generateKey func(reader io.Reader) crypto.PrivKey) {
 	var zero zeroReader
 	for i := 0; i < b.N; i++ {
-		GenerateKey(zero)
+		generateKey(zero)
 	}
 }
 

crypto/secp256k1/internal/secp256k1/curve.go

@@ -30,6 +30,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+// nolint:gocritic
 package secp256k1
 
 import (