Fixed panic due to predefiend func

Author: uudashr

gocognit.go

@@ -299,13 +299,16 @@ func (v *complexityVisitor) visitBinaryExpr(n *ast.BinaryExpr) ast.Visitor {
 }
 
 func (v *complexityVisitor) visitCallExpr(n *ast.CallExpr) ast.Visitor {
-	if name, ok := n.Fun.(*ast.Ident); ok {
-		if name.Obj == v.name.Obj && name.Name == v.name.Name {
+	if callIdent, ok := n.Fun.(*ast.Ident); ok {
+		obj, name := callIdent.Obj, callIdent.Name
+		if obj == v.name.Obj && name == v.name.Name {
 			// called by same function directly (direct recursion)
 			v.incComplexity()
-		} else if fnDecl, ok := name.Obj.Decl.(*ast.FuncDecl); ok {
-			// called by same function indirectly (indirect recursion)
-			ast.Walk(v, fnDecl)
+		} else if obj != nil {
+			if fnDecl, ok := obj.Decl.(*ast.FuncDecl); ok {
+				// called by same function indirectly (indirect recursion)
+				ast.Walk(v, fnDecl)
+			}
 		}
 	}
 	return v

testdata/src/a/a.go

@@ -7,6 +7,7 @@ import (
 )
 
 func HelloWorld() string {
+	_ = len("hello")
 	return "Hello, World!"
 } // total complexity = 0
 

testdata/src/b/b.go

@@ -7,6 +7,7 @@ import (
 )
 
 func HelloWorld() string {
+	_ = len("hello")
 	return "Hello, World!"
 } // total complexity = 0