diff --git a/_demo/interf/foo/foo.go b/_demo/interf/foo/foo.go
new file mode 100644
index 00000000..e385a31d
--- /dev/null
+++ b/_demo/interf/foo/foo.go
@@ -0,0 +1,9 @@
+package foo
+
+func Bar() any {
+	return struct{ V int }{1}
+}
+
+func F() any {
+	return struct{ v int }{1}
+}
diff --git a/_demo/interf/interf.go b/_demo/interf/interf.go
new file mode 100644
index 00000000..457e9e41
--- /dev/null
+++ b/_demo/interf/interf.go
@@ -0,0 +1,35 @@
+package main
+
+import (
+	"github.com/goplus/llgo/_demo/interf/foo"
+)
+
+func Foo() any {
+	return struct{ v int }{1}
+}
+
+func main() {
+	v := Foo()
+	if x, ok := v.(struct{ v int }); ok {
+		println(x.v)
+	} else {
+		println("Foo: not ok")
+	}
+	bar := foo.Bar()
+	if x, ok := bar.(struct{ V int }); ok {
+		println(x.V)
+	} else {
+		println("Bar: not ok")
+	}
+	if x, ok := foo.F().(struct{ v int }); ok {
+		println(x.v)
+	} else {
+		println("F: not ok")
+	}
+}
+
+/* Expected output:
+1
+1
+F: not ok
+*/
diff --git a/internal/abi/llgo_autogen.lla b/internal/abi/llgo_autogen.lla
index f2db6c47..0d23b976 100644
Binary files a/internal/abi/llgo_autogen.lla and b/internal/abi/llgo_autogen.lla differ
diff --git a/internal/abi/type.go b/internal/abi/type.go
index e7ecaf8f..b43621a9 100644
--- a/internal/abi/type.go
+++ b/internal/abi/type.go
@@ -193,6 +193,21 @@ type FuncType struct {
 	OutCount uint16 // top bit is set if last input parameter is ...
 }
 
+// In returns the number of input parameters of a function type.
+func (p *FuncType) In() int {
+	return int(p.InCount)
+}
+
+// Out returns the number of output results of a function type.
+func (p *FuncType) Out() int {
+	return int(p.OutCount &^ (1 << 15))
+}
+
+// Variadic reports whether the function type is variadic.
+func (p *FuncType) Variadic() bool {
+	return p.OutCount&(1<<15) != 0
+}
+
 type StructField struct {
 	Name   Name    // name is always non-empty
 	Typ    *Type   // type of field
@@ -219,10 +234,10 @@ type Text = unsafe.Pointer // TODO(xsw): to be confirmed
 
 // Method on non-interface type
 type Method struct {
-	Name_ Name  // name of method
-	Mtyp_ *Type // method type (without receiver)
-	Ifn_  Text  // fn used in interface call (one-word receiver)
-	Tfn_  Text  // fn used for normal method call
+	Name_ Name      // name of method
+	Mtyp_ *FuncType // method type (without receiver)
+	Ifn_  Text      // fn used in interface call (one-word receiver)
+	Tfn_  Text      // fn used for normal method call
 }
 
 // UncommonType is present only for defined types or types with methods
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index 0de68c73..e2f90b84 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ
diff --git a/internal/runtime/type.go b/internal/runtime/type.go
index 6b8f0e8e..36ce1a0f 100644
--- a/internal/runtime/type.go
+++ b/internal/runtime/type.go
@@ -10,9 +10,6 @@ import (
 	"github.com/goplus/llgo/internal/abi"
 )
 
-// type nameOff = abi.NameOff
-// type typeOff = abi.TypeOff
-
 type _type = abi.Type
 
 type interfacetype = abi.InterfaceType
diff --git a/internal/runtime/z_type.go b/internal/runtime/z_type.go
index 99de71c5..403c37b0 100644
--- a/internal/runtime/z_type.go
+++ b/internal/runtime/z_type.go
@@ -20,6 +20,7 @@ import (
 	"unsafe"
 
 	"github.com/goplus/llgo/internal/abi"
+	"github.com/goplus/llgo/internal/runtime/c"
 )
 
 type (
@@ -31,10 +32,61 @@ type (
 type Kind = abi.Kind
 type Type = abi.Type
 
+type FuncType = abi.FuncType
 type InterfaceType = abi.InterfaceType
 
 // -----------------------------------------------------------------------------
 
+// Func returns a function type.
+func Func(in, out []*Type, variadic bool) *FuncType {
+	const (
+		funcTypeHdrSize = unsafe.Sizeof(abi.FuncType{})
+		pointerSize     = unsafe.Sizeof(uintptr(0))
+	)
+
+	n := len(in) + len(out)
+	ptr := AllocU(funcTypeHdrSize + uintptr(n)*pointerSize)
+	c.Memset(ptr, 0, funcTypeHdrSize)
+
+	ret := (*abi.FuncType)(ptr)
+	ret.Size_ = pointerSize
+	ret.Hash = uint32(abi.Func) // TODO(xsw): hash
+	ret.Kind_ = uint8(abi.Func)
+	ret.InCount = uint16(len(in))
+	ret.OutCount = uint16(len(out))
+	if variadic {
+		ret.OutCount |= 1 << 15
+	}
+
+	data := (**Type)(c.Advance(ptr, int(funcTypeHdrSize)))
+	params := unsafe.Slice(data, n)
+	copy(params, in)
+	copy(params[len(in):], out)
+	return ret
+}
+
+// Imethod returns an interface method.
+func Imethod(name string, typ *FuncType, exported bool) abi.Imethod {
+	n := abi.NewName(name, "", exported, false)
+	return abi.Imethod{
+		Name_: n,
+		Typ_:  typ,
+	}
+}
+
+// Method returns a method.
+func Method(name string, typ *FuncType, fn abi.Text, exported bool) abi.Method {
+	n := abi.NewName(name, "", exported, false)
+	return abi.Method{
+		Name_: n,
+		Mtyp_: typ,
+		Ifn_:  fn,
+		Tfn_:  fn,
+	}
+}
+
+// -----------------------------------------------------------------------------
+
 // Named returns a named type.
 func Named(name string, typ *Type) *Type {
 	ret := *typ // TODO(xsw): named type