Note
The contents of this page are informational.
D. FLS Changelog¶
This page describes the changes that have been applied to the FLS itself to address changes and new features introduced in each Rust release. Every item listed in the “Language” section of the release note is reproduced here, along with the change that has been applied due to it.
Caution
This page is not an exhaustive list of all of the changes in a release, just the language changes that had an impact to the FLS. See the release notes for a full list of changes.
D.1. Language changes in Rust 1.79.0¶
Stabilize inline `const {}` expressions.
New section: Const Blocks
Prevent opaque types being instantiated twice with different regions within the same function.
No change: already described in 4.12.2:51
Stabilize WebAssembly target features that are in phase 4 and 5.
No change:
cfg
andcfg_attr
configuration predicates are not part of the FLS
Add the `redundant_lifetimes` lint to detect lifetimes which are semantically redundant.
No change: lints are not part of the FLS
Stabilize the `unnameable_types` lint for public types that can’t be named.
No change: lints are not part of the FLS
Enable debuginfo in macros, and stabilize `-C collapse-macro-debuginfo` and `#[collapse_debuginfo]`.
New section: Attribute collapse_debuginfo
Propagate temporary lifetime extension into `if` and `match` expressions.
Restrict promotion of `const fn` calls.
No change: already described in 7.4.1:6
Warn against refining impls of crate-private traits with `refining_impl_trait` lint.
No change: lints are not part of the FLS
Stabilize associated type bounds (RFC 2289).
New paragraph: 12.3:5
Stabilize importing `main` from other modules or crates.
No change: this lifted restriction was not previously described in the FLS
While updating the FLS to account for this feature, we realized that the way the FLS described crate types was incorrect. We rectified this:
New section: Program Entry Point
New glossary entry: crate type
Updated glossary entries: binary crate, library crate, proc-macro crate
Moved paragraph: 18.7:2
Check return types of function types for well-formedness
No change: the exact trait resolution implementation is not part of the FLS
Change inductive trait solver cycles to be ambiguous
No change: the exact trait solver is not part of the FLS
D.2. Language changes in Rust 1.78.0¶
Stabilize `#[cfg(target_abi = …)]`
No change:
cfg
andcfg_attr
configuration predicates are not part of the FLS
Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute
No change: tool attributes are not part of the FLS
Make async-fn-in-trait implementable with concrete signatures
No change: no paragraph in the FLS forbids this prior incompatability
Make matching on NaN a hard error, and remove the rest of `illegal_floating_point_literal_pattern`
New paragraph: 5.1.2:3
static mut: allow mutable reference to arbitrary types, not just slices and arrays
No change: this lifted restriction was not previously described in the FLS
Extend `invalid_reference_casting` to include references casting to bigger memory layout
No change: lints are not part of the FLS
Add `non_contiguous_range_endpoints` lint for singleton gaps after exclusive ranges
No change: lints are not part of the FLS
Add `wasm_c_abi` lint for use of older wasm-bindgen versions
No change: lints are not part of the FLS
Update `indirect_structural_match` and `pointer_structural_match` lints to match RFC
No change: lints are not part of the FLS
Make non-`PartialEq`-typed consts as patterns a hard error
No change: already described in 5.1.4:4
Split `refining_impl_trait` lint into `_reachable`, `_internal` variants
No change: lints are not part of the FLS
Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds
No change: the FLS does not specify type inference to such a degree
Weaken eager detection of cyclic types during type inference
No change: the FLS does not specify type inference to such a degree
`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Trait + Auto`
New paragraph: 4.12.3:29
D.3. language changes in Rust 1.77.0¶
Reveal opaque types within the defining body for exhaustiveness checking.
No change: the FLS does not specify introspection of the concrete type of the match expression scrutinee to such a degree
-
New section: C String Literals
-
No change: not a language change
Add lint `static_mut_refs` to warn on references to mutable statics.
No change: lints are not part of the FLS
Support async recursive calls (as long as they have indirection).
No change: this lifted restriction was not previously described in the FLS
Undeprecate lint `unstable_features` and make use of it in the compiler.
No change: lints are not part of the FLS
Make inductive cycles in coherence ambiguous always.
No change: the FLS does not describe the trait solver to such a degree
Get rid of type-driven traversal in const-eval interning, only as a future compatibility lint for now.
No change: this lifted restriction was not previously described in the FLS
Deny braced macro invocations in let-else.
New paragraph: 8.1:4