diff --git a/contrib/implements/internal/implements/gosrc.go b/contrib/implements/internal/implements/gosrc.go
index 33d586f..c8272b9 100644
--- a/contrib/implements/internal/implements/gosrc.go
+++ b/contrib/implements/internal/implements/gosrc.go
@@ -1,3 +1,4 @@
+// Package implements is internal
 package implements
 
 import (
@@ -37,7 +38,6 @@ type goFunction struct {
 	fullName        string
 	comment         string
 	implementsCFunc string
-	callsCFunc      string
 	isDeprecated    bool
 	isPreview       bool
 
@@ -114,7 +114,7 @@ func (v *visitor) checkCalled(s *ast.SelectorExpr) {
 	if !ok {
 		return
 	}
-	if "C" == ident.String() {
+	if ident.String() == "C" {
 		cname := s.Sel.String()
 		if ignoreCCalls[cname] {
 			return
diff --git a/contrib/implements/main.go b/contrib/implements/main.go
index 2070167..eee6a8e 100644
--- a/contrib/implements/main.go
+++ b/contrib/implements/main.go
@@ -82,7 +82,7 @@ func main() {
 		if err != nil {
 			abort(err.Error())
 		}
-		defer f.Close()
+		defer func() { _ = f.Close() }()
 		rpts = append(rpts, implements.NewJSONReport(o, f))
 	}
 	switch {
@@ -93,7 +93,7 @@ func main() {
 		if err != nil {
 			abort(err.Error())
 		}
-		defer f.Close()
+		defer func() { _ = f.Close() }()
 		rpts = append(rpts, implements.NewTextReport(o, f))
 	}
 	if len(rpts) == 0 {
@@ -136,6 +136,6 @@ func main() {
 		}
 	}
 	for _, r := range rpts {
-		r.Done()
+		_ = r.Done()
 	}
 }