fix: fix false-positive (#97)

Signed-off-by: Sasha Melentyev <sasha@m8.ru>

pkg/analyzer/analyzer.go

@@ -117,8 +117,9 @@ func run(pass *analysis.Pass) (interface{}, error) {
 
 		case *ast.BinaryExpr:
 			switch n.Op {
-			case token.LSS, token.GTR, token.LEQ, token.GEQ:
+			case token.LSS, token.GTR, token.LEQ, token.GEQ, token.QUO, token.ADD, token.SUB, token.MUL:
 				return
+			default:
 			}
 
 			x, ok := n.X.(*ast.SelectorExpr)
@@ -138,7 +139,6 @@ func run(pass *analysis.Pass) (interface{}, error) {
 			if ok {
 				switchStmt(pass, x, n.Body.List)
 			}
-
 		}
 	})
 

pkg/analyzer/testdata/src/a/http/issue96.go

@@ -0,0 +1,28 @@
+package http_test
+
+import (
+	"net/http"
+)
+
+func _() error {
+	resp, err := http.DefaultClient.Do(&http.Request{})
+	if err != nil {
+		return err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode/100 != 2 {
+		return nil
+	}
+	if resp.StatusCode+100 != 2 {
+		return nil
+	}
+	if resp.StatusCode-100 != 2 {
+		return nil
+	}
+	if resp.StatusCode*100 != 2 {
+		return nil
+	}
+
+	return nil
+}