if isFormatter(typ) {
		return "", false
	}

	// Does e allow e.String() or e.Error()?
	strObj, _, _ := types.LookupFieldOrMethod(typ, false, pass.Pkg, "String")
	strMethod, strOk := strObj.(*types.Func)
	errObj, _, _ := types.LookupFieldOrMethod(typ, false, pass.Pkg, "Error")
	errMethod, errOk := errObj.(*types.Func)
	if !strOk && !errOk {
		return "", false
	}

	}
	// verify that lookup finds the same method in both interfaces (redundant check)
	obj, _, _ := LookupFieldOrMethod(et, false, nil, "Error")
	if obj != want {
		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", et, obj, obj, want, want)
	}
	obj, _, _ = LookupFieldOrMethod(it, false, nil, "Error")
	if obj != want {
		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", it, obj, obj, want, want)
	}
}

	}
	// verify that lookup finds the same method in both interfaces (redundant check)
	obj, _, _ := LookupFieldOrMethod(et, false, nil, "Error")
	if obj != want {
		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", et, obj, obj, want, want)
	}
	obj, _, _ = LookupFieldOrMethod(it, false, nil, "Error")
	if obj != want {
		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", it, obj, obj, want, want)
	}
}

		// Check ExampleFoo_Method and ExampleFoo_BadMethod.
		found := false
		// Check if Foo.Method exists in this package or its imports.
		for _, obj := range objs {
			if obj, _, _ := types.LookupFieldOrMethod(obj.Type(), true, obj.Pkg(), mmbr); obj != nil {
				found = true
				break
			}
		}
		if !found {
			pass.Reportf(fn.Pos(), "%s refers to unknown field or method: %s.%s", fnName, ident, mmbr)
		}
	}

}

func TestLookupFieldOrMethodOnNil(t *testing.T) {
	// LookupFieldOrMethod on a nil type is expected to produce a run-time panic.
	defer func() {
		const want = "LookupFieldOrMethod on nil type"
		p := recover()
		if s, ok := p.(string); !ok || s != want {
			t.Fatalf("got %v, want %s", p, want)
		}
	}()
	LookupFieldOrMethod(nil, false, nil, "")
}

func TestLookupFieldOrMethod(t *testing.T) {

	// x.typ is incomplete.
	if wantType {
		check.errorf(e.Sel, NotAType, "%s is not a type", syntax.Expr(e))
		goto Error
	}

	obj, index, indirect = lookupFieldOrMethod(x.typ, x.mode == variable, check.pkg, sel, false)
	if obj == nil {
		// Don't report another error if the underlying type was invalid (go.dev/issue/49541).
		if !isValid(under(x.typ)) {
			goto Error
		}

}

func TestLookupFieldOrMethodOnNil(t *testing.T) {
	// LookupFieldOrMethod on a nil type is expected to produce a run-time panic.
	defer func() {
		const want = "LookupFieldOrMethod on nil type"
		p := recover()
		if s, ok := p.(string); !ok || s != want {
			t.Fatalf("got %v, want %s", p, want)
		}
	}()
	LookupFieldOrMethod(nil, false, nil, "")
}

func TestLookupFieldOrMethod(t *testing.T) {

			check.use(arg0)
			return
		}

		check.expr(nil, x, selx.X)
		if x.mode == invalid {
			return
		}

		base := derefStructPtr(x.typ)
		sel := selx.Sel.Name
		obj, index, indirect := lookupFieldOrMethod(base, false, check.pkg, sel, false)
		switch obj.(type) {
		case nil:
			check.errorf(x, MissingFieldOrMethod, invalidArg+"%s has no single field %s", base, sel)
			return
		case *Func:

		if xi != nil {
			// All xi methods must exist in y and corresponding signatures must unify.
			xmethods := xi.typeSet().methods
			for _, xm := range xmethods {
				obj, _, _ := LookupFieldOrMethod(y, false, xm.pkg, xm.name)
				if ym, _ := obj.(*Func); ym == nil || !u.nify(xm.typ, ym.typ, exact, p) {
					return false
				}
			}
			return true
		}
	}

			check.use(arg0)
			return
		}

		check.expr(nil, x, selx.X)
		if x.mode == invalid {
			return
		}

		base := derefStructPtr(x.typ)
		sel := selx.Sel.Value
		obj, index, indirect := lookupFieldOrMethod(base, false, check.pkg, sel, false)
		switch obj.(type) {
		case nil:
			check.errorf(x, MissingFieldOrMethod, invalidArg+"%s has no single field %s", base, sel)
			return
		case *Func: