1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package typeutil
6
7import (
8	"go/ast"
9	"go/types"
10)
11
12// StaticCallee returns the target (function or method) of a static
13// function call, if any. It returns nil for calls to builtin.
14func StaticCallee(info *types.Info, call *ast.CallExpr) *types.Func {
15	var obj types.Object
16	switch fun := call.Fun.(type) {
17	case *ast.Ident:
18		obj = info.Uses[fun] // type, var, builtin, or declared func
19	case *ast.SelectorExpr:
20		if sel, ok := info.Selections[fun]; ok {
21			obj = sel.Obj() // method or field
22		} else {
23			obj = info.Uses[fun.Sel] // qualified identifier?
24		}
25	}
26	if f, ok := obj.(*types.Func); ok && !interfaceMethod(f) {
27		return f
28	}
29	return nil
30}
31
32func interfaceMethod(f *types.Func) bool {
33	recv := f.Type().(*types.Signature).Recv()
34	return recv != nil && types.IsInterface(recv.Type())
35}
36