2016-03-04.md

Subteam report: lang 2016-03-04

Highlights

Seeing as many of us were on vacation, we decided to hold a special meeting this week discussing possible designs for int generics, along with special guest @eddyb. The goal is to design a "max min" proposal that can have us making progress on the basic issues while skirting some of the more complex topics (notably: how far to go in determining constant equality.) Expect to see some concrete write-ups soon(ish).

--nmatsakis

Dashboard

RFC phase

• PR #197: ManuallyDrop type gives precise control of dtors of inline data.
• PR #1062: Constants that depend on type parameters in generic code
• PR #1148: Mutually exclusive traits
• PR #1177: Anonymous/placeholder lifetime "'_".
• PR #1180: Propose Interior<T> data-type, to allow moves out of the dropped value during the drop hook.
• PR #1201: Add support for naked functions.
• PR #1248: Safe intrinsics RFC
• PR #1296: RFC: Add an alias attribute to #[link] and -l
• PR #1305: Abstract output type parameters
• PR #1319: Amend RFC1228 with operator fixity and precedence
• PR #1321: Unstable visibility RFC
• PR #1327: Dropck Eyepatch RFC.
• PR #1346: Unsafe expressions
• PR #1358: RFC: Add #[repr(align = "N")]
• PR #1373: Remove some kinds of doc comments
• PR #1379: Change thread local variables to only accept async-signal-safe types.
• PR #1398: Allocators, take III
• PR #1399: RFC: Add #[repr(pack = "N")]
• PR #1406: Rfc: delegation of implementation
• PR #1408: Delayed resolution
• PR #1414: Add Rvalue-static-promotion RFC
• PR #1422: pub(restricted) item
• PR #1426: Placement in/box refinement
• PR #1429: Feature gate extern fn methods
• PR #1431: Statically dispatched methods for trait objects with associated data
• PR #1437: ESC byte escape
• PR #1440: RFC - Allow Drop types in statics/const functions
• PR #1444: RFC: native C-compatible unions via built-in syntax macro union!
• PR #1449: Add language support for bitfields
• PR #1450: Types for enum variants
• PR #1459: Add a used attribute
• PR #1477: Generic atomic v2
• PR #1478: translate undefined intrinsics to an unreachable and a lint
• PR #1492: RFC: .. in patterns
• PR #1494: Amend RFC 550 with misc. follow set corrections
• PR #1513: RFC: Stabilize implementing panics as aborts
• PR #1521: Copy clone semantics

Implementation phase

• Issue #13231: opt-in built-in bounds traits RFC tracker
• Issue #18469: Implement revised coercion rules
• Issue #22181: box and in expressions (tracking issue for RFC 809)
• Issue #27060: repr(packed) allows invalid unaligned loads
• Issue #27336: Tracking Issue for RFC 213: Default Type Parameter Fallback
• Issue #28237: Tracking issue for ... inclusive ranges (RFC #1192)
• Issue #31434: Restrict use of constants in patterns (RFC 1445)
• Issue #31436: ? operator and catch expressions (RFC 243)
• Issue #31844: Tracking issue for specialization (RFC 1210)

High priority issues

• Issue #15536: floating point to floating point casts have undefined behaviour
• Issue #22889: Duplicate inherent static methods can be defined in separate impl blocks
• Issue #25860: Implied bounds on nested references + variance = soundness hole
• Issue #28514: Private trait's methods reachable through a public subtrait
• Issue #29149: Lifetime bounds in Copy impls are ignored
• Issue #29859: Cyclic traits allow arbitrary traits to be synthesized
• Issue #30127: Desugared x.index(y) is not equivalent to x[y]
• Issue #31287: Pattern guard can consume value that is being matched

Needs decision

• Issue #21232: borrow-checker allows partial reinit of struct that has been moved away, but no use of it.
• Issue #23818: print! macro should flush stdout
• Issue #30191: Can't provide non-overlapping impls with any type parameters, if a blanket impl exists