// The Scopes mapping does not contain an entry for the
	// function body ([*ast.BlockStmt]); the function's scope is
	// associated with the [*ast.FuncType].
	//
	// The following node types may appear in Scopes:
	//
	//     *ast.File
	//     *ast.FuncType
	//     *ast.TypeSpec
	//     *ast.BlockStmt
	//     *ast.IfStmt
	//     *ast.SwitchStmt
	//     *ast.TypeSwitchStmt
	//     *ast.CaseClause

	// The Scopes mapping does not contain an entry for the
	// function body ([*ast.BlockStmt]); the function's scope is
	// associated with the [*ast.FuncType].
	//
	// The following node types may appear in Scopes:
	//
	//     *syntax.File
	//     *syntax.FuncType
	//     *syntax.TypeDecl
	//     *syntax.BlockStmt
	//     *syntax.IfStmt
	//     *syntax.SwitchStmt
	//     *syntax.CaseClause

				p.printFieldList(n.FieldList, n.TagList, _Semi)
				p.print(outdent, newline)
			} else {
				p.printFieldList(n.FieldList, n.TagList, _Semi)
			}
		}
		p.print(_Rbrace)

	case *FuncType:
		p.print(_Func)
		p.printSignature(n)

	case *InterfaceType:
		p.print(_Interface)
		if p.linebreaks && len(n.MethodList) > 1 {
			p.print(blank)
			p.print(_Lbrace)
			p.print(newline, indent)

			if !isValid(typ.base) {
				return Typ[Invalid]
			}
			return typ
		}

		check.errorf(e0, NotAType, "%s is not a type", e0)
		check.use(e0)

	case *syntax.FuncType:
		typ := new(Signature)
		setDefType(def, typ)
		check.funcType(typ, nil, nil, e)
		return typ

	case *syntax.InterfaceType:
		typ := check.newInterface()
		setDefType(def, typ)
		check.interfaceType(typ, e, def)
		return typ

		typ.base = Typ[Invalid] // avoid nil base in invalid recursive type declaration
		setDefType(def, typ)
		typ.base = check.varType(e.X)
		return typ

	case *ast.FuncType:
		typ := new(Signature)
		setDefType(def, typ)
		check.funcType(typ, nil, e)
		return typ

	case *ast.InterfaceType:
		typ := check.newInterface()
		setDefType(def, typ)
		check.interfaceType(typ, e, def)
		return typ

		// Note: don't try to resolve n.Sel, as we don't support qualified
		// resolution.

	case *ast.StructType:
		r.openScope(n.Pos())
		defer r.closeScope()
		r.walkFieldList(n.Fields, ast.Var)

	case *ast.FuncType:
		r.openScope(n.Pos())
		defer r.closeScope()
		r.walkFuncType(n)

	case *ast.CompositeLit:
		if n.Type != nil {
			ast.Walk(r, n.Type)
		}
		for _, e := range n.Elts {

				}
			}
		})
	}
}

// TestFuncType tests that an ast.FuncType with a nil Params field
// can be printed (per go/ast specification). Test case for issue 3870.
func TestFuncType(t *testing.T) {
	src := &ast.File{
		Name: &ast.Ident{Name: "p"},
		Decls: []ast.Decl{
			&ast.FuncDecl{
				Name: &ast.Ident{Name: "f"},
				Type: &ast.FuncType{},
			},
		},
	}

	var buf bytes.Buffer

// inadvertently copy a lock, by checking whether
// its receiver, parameters, or return values
// are locks.
func checkCopyLocksFunc(pass *analysis.Pass, name string, recv *ast.FieldList, typ *ast.FuncType) {
	if recv != nil && len(recv.List) > 0 {
		expr := recv.List[0].Type
		if path := lockPath(pass.Pkg, pass.TypesInfo.Types[expr].Type, nil); path != nil {

	// Most of it is bottom-up, but in a few places we need
	// to know the type of the function we are checking.
	// The before function records that information on
	// the curfn stack.
	var curfn []*ast.FuncType

	before := func(n any) {
		// push function type on stack
		switch n := n.(type) {
		case *ast.FuncDecl:
			curfn = append(curfn, n.Type)
		case *ast.FuncLit:
			curfn = append(curfn, n.Type)
		}

			r := TypeExpr(f, pkg, t.Results().At(i).Type())
			if r == nil {
				return nil
			}
			returns = append(returns, &ast.Field{
				Type: r,
			})
		}
		return &ast.FuncType{
			Params: &ast.FieldList{
				List: params,
			},
			Results: &ast.FieldList{
				List: returns,
			},
		}
	case interface{ Obj() *types.TypeName }: // *types.{Alias,Named,TypeParam}