document Rust 1.90 changes

src/changelog.rst

@@ -18,6 +18,37 @@ with the change that has been applied due to it.
    just the language changes that had an impact to the FLS. See the `release
    notes`_ for a full list of changes.
 
+Language changes in Rust 1.90.0
+-------------------------------
+
+- `Split up the unknown_or_malformed_diagnostic_attributes lint <https://github.com/rust-lang/rust/pull/140717>`_
+
+  - No change: lints are not part of the FLS
+
+- `Allow constants whose final value has references to mutable/external memory, but reject such constants as patterns <https://github.com/rust-lang/rust/pull/140942>`_
+
+  - This lifted restriction was not specified in the FLS
+  - The restriction on patterns is documented in :p:`fls_wJ9f906BlBvg`
+  - New paragraph: :p:`fls_zyuxqty09SDO`
+
+    - Above paragraph replaces :p:`fls_6g7c1kjrmfnr` and :p:`fls_hkbwa8xx2fwx`
+
+  * New paragraphs:
+
+    - :p:`fls_ooOYxhVh8hZo`
+
+    - :p:`fls_zkNFeBLy80UA`
+
+    - :p:`fls_VhzGfnWg7YrG`
+
+    - :p:`fls_ibYKKQdB2tDn`
+
+    - :p:`fls_dQdSxf8kOgbi`
+
+- `Allow volatile access to non-Rust memory, including address 0 <https://github.com/rust-lang/rust/pull/141260>`_
+
+  - No change: lints are not part of the FLS
+
 Language changes in Rust 1.89.0
 -------------------------------
 
@@ -317,6 +348,8 @@ Language changes in Rust 1.83.0
 
   * Changed paragraphs: :p:`fls_to4e7imq2c0w`, :p:`fls_6g7c1kjrmfnr`, :p:`fls_hkbwa8xx2fwx`
 
+  * Removed paragraph: :p:`fls_ox6sgl9n43g2`
+
 * `Allow creating references to statics in \`const\` initializers. <https://github.com/rust-lang/rust/pull/129759>`_
 
   * No change: This previous restriction is not specified in the FLS

src/expressions.rst

@@ -209,9 +209,6 @@ involve :t:`[type]s` that require :t:`destruction`:
 * :dp:`fls_b5fraqx07wuo`
   :t:`[If let expression]s`,
 
-* :dp:`fls_6g7c1kjrmfnr`
-  :t:`[Immutable borrow expression]s`.
-
 * :dp:`fls_rpapnm3afan8`
   :t:`[Index expression]s`,
 
@@ -248,9 +245,6 @@ involve :t:`[type]s` that require :t:`destruction`:
 * :dp:`fls_3bucpdj828bq`
   :t:`[Range expression]s`,
 
-* :dp:`fls_hkbwa8xx2fwx`
-  :t:`[Borrow]s`,
-
 * :dp:`fls_fobs8ebt7dhc`
   :t:`[Struct expression]s`,
 
@@ -271,6 +265,12 @@ involve :t:`[type]s` that require :t:`destruction`:
 * :dp:`fls_qvofy4wkql0s`
   :t:`[While loop expression]s`.
 
+* :dp:`fls_zyuxqty09SDO`
+  All forms of :t:`[borrow]s` except those of expressions that are subject to
+  :t:`drop scope extension` to the end of the program
+  and which are either :t:`[mutable borrow]s`
+  or borrows of expressions that result in values with :t:`interior mutability`.
+
 :dp:`fls_3i7efddbsmn0`
 An :t:`expression` is not considered a :t:`constant expression` when it
 explicitly invokes an :t:`associated trait function` or uses
@@ -312,10 +312,6 @@ A :t:`constant context` is a :t:`construct` that requires a
 * :dp:`fls_ucFupTeCyylb`
   The :t:`block expression` of a :t:`const block expression`.
 
-:dp:`fls_ox6sgl9n43g2`
-It is a static error to create a :t:`mutable reference` in a
-:t:`constant context`.
-
 :dp:`fls_od0h3v40kjp6`
 An invocation of the :std:`core::ptr::addr_of` :t:`macro` expands to a
 :t:`constant expression` allowed in any :t:`constant context` and

src/patterns.rst

@@ -370,6 +370,12 @@ When a :t:`path pattern` refers to an :t:`associated constant` or a
 :t:`constant`, the :t:`type` of the :t:`associated constant` or :t:`constant`
 shall be :t:`structurally equal`.
 
+:dp:`fls_wJ9f906BlBvg`
+When a :t:`path pattern` refers to an :t:`associated constant` or a
+:t:`constant`, the :t:`constant` must not contain any references to
+:t:`[mutable static]s`, :t:`[static]s` with :t:`interior mutability`,
+or :t:`[external static]s`.
+
 :dp:`fls_hF19K8sWU8FF`
 When the type of the :t:`path pattern` is of an :t:`enum type` or
 :t:`struct type`, then the :t:`enum type` or :t:`struct type` shall be subject

src/values.rst

@@ -111,6 +111,22 @@ The :t:`expression` of a :t:`constant initializer` shall be a
 The value of a :t:`constant` is determined by evaluating its
 :t:`constant initializer`.
 
+:dp:`fls_ooOYxhVh8hZo`
+After :t:`type coercion`, the value of the constant cannot contain any
+:t:`[mutable reference]s`, except when
+
+- :dp:`fls_zkNFeBLy80UA`
+  The :t:`mutable reference` is contained within an :t:`external static`, or
+
+- :dp:`fls_VhzGfnWg7YrG`
+  The :t:`mutable reference` is contained within a :t:`mutable static`, or
+
+- :dp:`fls_ibYKKQdB2tDn`
+  The :t:`mutable reference` is contained within an :t:`union`, or
+
+- :dp:`fls_dQdSxf8kOgbi`
+  The :t:`referent` is a value of a :t:`zero-sized type`.
+
 .. rubric:: Dynamic Semantics
 
 :dp:`fls_xezt9hl069h4`

version.rst

@@ -1,4 +1,4 @@
 .. SPDX-License-Identifier: MIT OR Apache-2.0
    SPDX-FileCopyrightText: The Ferrocene Developers
    SPDX-FileCopyrightText: The Rust Project Developers
-.. |spec_version| replace:: 1.88.0
+.. |spec_version| replace:: 1.90.0