method lookup fails on on struct with interface field

[mvertes]

The following program sample.go triggers an unexpected result

package main

type Core interface {
    Enabler
}

type Enabler interface {
    Enabled() bool
}

type Logger struct {
    core Core
}

func (log *Logger) GetCore() Core { return log.core }

type T struct{}

func (t *T) Enabled() bool { return true }

func main() {
    base := &Logger{&T{}}
    println(base.GetCore().Enabled())
}

Expected result

$ go run ./sample.go
true

Got

$ yaegi ./sample.go
./sample.go:23:10: panic
run: runtime error: invalid memory address or nil pointer dereference
goroutine 1 [running]:
runtime/debug.Stack(0x1, 0x14000090400, 0x40)
	/Users/marc/sdk/go1.16.6/src/runtime/debug/stack.go:24 +0x88
github.com/traefik/yaegi/interp.(*Interpreter).eval.func1(0x140000a5bf0)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/interp.go:504 +0x94
panic(0x104adcf20, 0x10506eae0)
	/Users/marc/sdk/go1.16.6/src/runtime/panic.go:965 +0x14c
github.com/traefik/yaegi/interp.runCfg.func1(0x1400036e160, 0x14000095100, 0x140000a59c0)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/run.go:185 +0x1e8
panic(0x104adcf20, 0x10506eae0)
	/Users/marc/sdk/go1.16.6/src/runtime/panic.go:965 +0x14c
github.com/traefik/yaegi/interp.getMethodByName.func1(0x1400036e160, 0x1400011ab40)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/run.go:1845 +0x174
github.com/traefik/yaegi/interp.runCfg(0x14000095100, 0x1400036e160)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/run.go:191 +0x8c
github.com/traefik/yaegi/interp.(*Interpreter).run(0x1400036c000, 0x14000094500, 0x1400036e000)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/run.go:122 +0x244
github.com/traefik/yaegi/interp.(*Interpreter).eval(0x1400036c000, 0x140001c69a0, 0x151, 0x16bd9b798, 0x1e, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/interp.go:596 +0x5e8
github.com/traefik/yaegi/interp.(*Interpreter).EvalPath(0x1400036c000, 0x16bd9b798, 0x1e, 0x140001c6800, 0x151, 0x0, 0x0, 0x0)
	/Users/marc/go/src/github.com/traefik/yaegi2/interp/interp.go:418 +0xc4
main.runFile(0x1400036c000, 0x16bd9b798, 0x1e, 0x0, 0x0, 0x0)
	/Users/marc/go/src/github.com/traefik/yaegi2/cmd/yaegi/run.go:149 +0x84
main.run(0x140001c0010, 0x1, 0x1, 0x14000182480, 0x14000073ea8)
	/Users/marc/go/src/github.com/traefik/yaegi2/cmd/yaegi/run.go:112 +0x830
main.main()
	/Users/marc/go/src/github.com/traefik/yaegi2/cmd/yaegi/yaegi.go:144 +0x324

Yaegi Version

0.9.21

Additional Notes

No response

[mvertes]

issue related to #1172, after #1207 is applied.