panic: reflect.Value.Convert: value of type error cannot be converted to type

[iyear]

The following program sample.go triggers an unexpected result

package main

type Err struct {
	err string
}

func (e Err) Error() string {
	return e.err
}

func main() {
	var E = Err{"error"}
	var err error = E

	switch err {
	case nil:
	case E:
	}
}

Expected result

No output, but running normally

Got

e.go:12:10: panic
run: reflect.Value.Convert: value of type error cannot be converted to type struct { Xerr string }
goroutine 1 [running]:
runtime/debug.Stack()
        .../runtime/debug/stack.go:24 +0x5e
github.com/traefik/yaegi/interp.(*Interpreter).Execute.func1()
        .../github.com/traefik/[email protected]/interp/program.go:146 +0x7e
panic({0xfdea20?, 0xc000043f10?})
        .../runtime/panic.go:914 +0x21f
github.com/traefik/yaegi/interp.runCfg.func1()
        .../github.com/traefik/[email protected]/interp/run.go:205 +0x185
panic({0xfdea20?, 0xc000043f10?})
        .../runtime/panic.go:914 +0x21f
reflect.Value.Convert({0x1038aa0?, 0xc000043e90?, 0xc00008aa80?}, {0x12e6108, 0xc00008aa80})
        .../reflect/value.go:3319 +0x12c
github.com/traefik/yaegi/interp._case.func7(0xc0000ca630?)
        .../github.com/traefik/[email protected]/interp/run.go:3115 +0x1b7
github.com/traefik/yaegi/interp.runCfg(0xc000331b80, 0xc0000ca630, 0x4?, 0x0?)
        .../github.com/traefik/[email protected]/interp/run.go:213 +0x285
github.com/traefik/yaegi/interp.(*Interpreter).run(0xc0000dd440, 0xc000330dc0, 0xc0000ca420?)
        .../github.com/traefik/[email protected]/interp/run.go:119 +0x3c5
github.com/traefik/yaegi/interp.(*Interpreter).Execute(0xc0000dd440, 0xc000334930)
        .../github.com/traefik/[email protected]/interp/program.go:172 +0x225
github.com/traefik/yaegi/interp.(*Interpreter).eval(0xc0000dd440, {0xc000210840?, 0xbd?}, {0xc00000a0d0?, 0x200?}, 0xc0?)
        .../github.com/traefik/[email protected]/interp/interp.go:565 +0x55
github.com/traefik/yaegi/interp.(*Interpreter).EvalPath(0xc0000dd440, {0xc00000a0d0, 0x4})
        .../github.com/traefik/[email protected]/interp/interp.go:514 +0xa6
main.runFile(0xc00000a0d0?, {0xc00000a0d0, 0x4}, 0x0)
        .../github.com/traefik/[email protected]/cmd/yaegi/run.go:153 +0xd7
main.run({0xc0000880a0?, 0x1, 0x2})
        .../github.com/traefik/[email protected]/cmd/yaegi/run.go:116 +0xb97
main.main()
        .../github.com/traefik/[email protected]/cmd/yaegi/yaegi.go:133 +0xca

Yaegi Version

v0.15.1

Additional Notes

No response