fix issue #355 (#356)

fixtures/modifies-param.go

@@ -1,26 +1,25 @@
 package fixtures
 
-import (
-	"go/ast"
-)
-
 func one(a int) {
- a,b:= 1,2 // MATCH /parameter 'a' seems to be modified/
- a++ // MATCH /parameter 'a' seems to be modified/
+	a, b := 1, 2 // MATCH /parameter 'a' seems to be modified/
+	a++          // MATCH /parameter 'a' seems to be modified/
 }
 
 func two(b, c float32) {
-    if c>0.0 {
-        b = 1 // MATCH /parameter 'b' seems to be modified/
-    }
+	if c > 0.0 {
+		b = 1 // MATCH /parameter 'b' seems to be modified/
+	}
 }
 
 type foo struct {
-    a string
+	a string
 }
 
 func three(s *foo) {
-    s.a = "foooooo"
+	s.a = "foooooo"
 }
 
-
+// non regression test for issue 355
+func issue355(_ *foo) {
+	_ = "foooooo"
+}

rule/modifies-param.go

@@ -37,6 +37,10 @@ func retrieveParamNames(pl []*ast.Field) map[string]bool {
 	result := make(map[string]bool, len(pl))
 	for _, p := range pl {
 		for _, n := range p.Names {
+			if n.Name == "_" {
+				continue
+			}
+
 			result[n.Name] = true
 		}
 	}