all: remove redundant type conversion

Change-Id: I4de1d39f8b72cd1116c56fb00b224a60de035f9e
GitHub-Last-Rev: 4e40ee8059695468e62ba9213058b5cc1e4a8e0a
GitHub-Pull-Request: golang/oauth2#586
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/428982
Reviewed-by: Cody Oss <codyoss@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/google/jwt_test.go b/google/jwt_test.go
index 043f445..5890ae9 100644
--- a/google/jwt_test.go
+++ b/google/jwt_test.go
@@ -73,7 +73,7 @@
 		t.Fatalf("base64 DecodeString: %v\nString: %q", err, parts[0])
 	}
 	var hdr jws.Header
-	if err := json.Unmarshal([]byte(hdrJSON), &hdr); err != nil {
+	if err := json.Unmarshal(hdrJSON, &hdr); err != nil {
 		t.Fatalf("json.Unmarshal: %v (%q)", err, hdrJSON)
 	}
 
@@ -129,7 +129,7 @@
 		t.Fatalf("base64 DecodeString: %v\nString: %q", err, parts[0])
 	}
 	var hdr jws.Header
-	if err := json.Unmarshal([]byte(hdrJSON), &hdr); err != nil {
+	if err := json.Unmarshal(hdrJSON, &hdr); err != nil {
 		t.Fatalf("json.Unmarshal: %v (%q)", err, hdrJSON)
 	}
 
diff --git a/jira/jira.go b/jira/jira.go
index 39aa713..814656e 100644
--- a/jira/jira.go
+++ b/jira/jira.go
@@ -105,7 +105,7 @@
 	if err != nil {
 		return nil, err
 	}
-	v.Set("assertion", string(assertion))
+	v.Set("assertion", assertion)
 
 	// Fetch access token from auth server
 	hc := oauth2.NewClient(js.ctx, nil)
diff --git a/jws/jws.go b/jws/jws.go
index 683d2d2..9501564 100644
--- a/jws/jws.go
+++ b/jws/jws.go
@@ -178,5 +178,5 @@
 
 	h := sha256.New()
 	h.Write([]byte(signedContent))
-	return rsa.VerifyPKCS1v15(key, crypto.SHA256, h.Sum(nil), []byte(signatureString))
+	return rsa.VerifyPKCS1v15(key, crypto.SHA256, h.Sum(nil), signatureString)
 }