diff --git a/internal/encoding/text/decode.go b/internal/encoding/text/decode.go
index eb10ea102..37803773f 100644
--- a/internal/encoding/text/decode.go
+++ b/internal/encoding/text/decode.go
@@ -381,7 +381,7 @@ func (d *Decoder) currentOpenKind() (Kind, byte) {
 	case '[':
 		return ListOpen, ']'
 	}
-	panic(fmt.Sprintf("Decoder: openStack contains invalid byte %s", string(openCh)))
+	panic(fmt.Sprintf("Decoder: openStack contains invalid byte %c", openCh))
 }
 
 func (d *Decoder) pushOpenStack(ch byte) {
diff --git a/testing/prototest/message.go b/testing/prototest/message.go
index e495628d1..c104605fa 100644
--- a/testing/prototest/message.go
+++ b/testing/prototest/message.go
@@ -643,7 +643,7 @@ func formatValue(v pref.Value) string {
 		if err != nil {
 			return fmt.Sprintf("<%v>", err)
 		}
-		return fmt.Sprintf("%v{%v}", v.Descriptor().FullName(), string(b))
+		return fmt.Sprintf("%v{%s}", v.Descriptor().FullName(), b)
 	case string:
 		return fmt.Sprintf("%q", v)
 	default: