Method getNarrowedType

internal/checker/flow.go:833–844

(t *Type, candidate *Type, assumeTrue bool, checkDerived bool)

}

func (c *Checker) getNarrowedType(t *Type, candidate *Type, assumeTrue bool, checkDerived bool) *Type {
	if t.flags&TypeFlagsUnion == 0 {
		return c.getNarrowedTypeWorker(t, candidate, assumeTrue, checkDerived)
	}
	key := NarrowedTypeKey{t, candidate, assumeTrue, checkDerived}
	if narrowedType, ok := c.narrowedTypes[key]; ok {
		return narrowedType
	}
	narrowedType := c.getNarrowedTypeWorker(t, candidate, assumeTrue, checkDerived)
	c.narrowedTypes[key] = narrowedType
	return narrowedType
}

func (c *Checker) getNarrowedTypeWorker(t *Type, candidate *Type, assumeTrue bool, checkDerived bool) *Type {
	if !assumeTrue {