This proposal provides an `as` expression for casting. This supports implicit conversions plus some safe and unsurprising conversions that we do not support implicitly:
* lossy but fully defined conversions to floating-point types
* conversion from `bool` to integer types
* conversion between adaptors and their adapted type, and more generally between compatible types
This facility can be extended by implementing the `As(TargetType)` interface for a type.
Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
Proposal to support a limited set of implicit conversions.
This would generally permit only implicit conversions that are lossless and semantics-preserving. In particular, this proposal allows:
- Conversion from an integer type to a wider integer type of the same signedness, and from an unsigned integer type to a wider signed integer type.
- Conversion from an integer type to a floating-point type that has enough mantissa bits to exactly represent all integers in the source type.
- Conversion from integer literals to integer and floating-point types that can represent them.
- Conversion from floating-point literals to floating-point types that can represent them.
- Conversions required for generics: conversions of values between facet types, and conversions of types between type-of-types, as described in the generics proposals.
- Conversions required for inheritance: derived-to-base conversions for class pointers and class values.
Other conversions, such as lossy conversions between arithmetic types and conversions between bool and other types are not supported.
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Geoff Romer <gromer@google.com>