make date-check lightweight

This avoids having to write the date twice when updating date-check.

Before "As of <-- 2022-07 --> July 2022"
After "As of July 2022"

Author: tshepang

Diff for: ci/date-check/src/main.rs

@@ -3,9 +3,10 @@ use std::{
     convert::TryInto as _,
     env, fmt, fs,
     path::{Path, PathBuf},
+    str::FromStr,
 };
 
-use chrono::{Datelike as _, TimeZone as _, Utc};
+use chrono::{Datelike as _, Month, TimeZone as _, Utc};
 use glob::glob;
 use regex::Regex;
 
@@ -36,16 +37,7 @@ impl fmt::Display for Date {
 }
 
 fn make_date_regex() -> Regex {
-    Regex::new(
-        r"(?x) # insignificant whitespace mode
-        <!--\s*
-        [dD]ate:\s*
-        (?P<y>\d{4}) # year
-        -
-        (?P<m>\d{2}) # month
-        \s*-->",
-    )
-    .unwrap()
+    Regex::new(r"[aA]s of (\w+) (\d{4})").unwrap()
 }
 
 fn collect_dates_from_file(date_regex: &Regex, text: &str) -> Vec<(usize, Date)> {
@@ -57,8 +49,8 @@ fn collect_dates_from_file(date_regex: &Regex, text: &str) -> Vec<(usize, Date)>
             (
                 cap.get(0).unwrap().range(),
                 Date {
-                    year: cap["y"].parse().unwrap(),
-                    month: cap["m"].parse().unwrap(),
+                    year: cap[2].parse().unwrap(),
+                    month: Month::from_str(&cap[1]).unwrap().number_from_month(),
                 },
             )
         })
@@ -183,20 +175,18 @@ mod tests {
     #[test]
     fn test_date_regex() {
         let regex = make_date_regex();
-        assert!(regex.is_match("foo <!-- date: 2021-01 --> bar"));
-    }
-
-    #[test]
-    fn test_date_regex_capitalized() {
-        let regex = make_date_regex();
-        assert!(regex.is_match("foo <!-- Date: 2021-08 --> bar"));
+        assert!(regex.is_match("As of July 2022"));
+        assert!(regex.is_match("As of Jul 2022"));
+        assert!(regex.is_match("As of july 2022"));
+        assert!(regex.is_match("As of jul 2022"));
+        assert!(regex.is_match("as of jul 2022"));
     }
 
     #[test]
     fn test_collect_dates_from_file() {
-        let text = "Test1\n<!-- date: 2021-01 -->\nTest2\nFoo<!-- date: 2021-02 \
-                    -->\nTest3\nTest4\nFoo<!-- date: 2021-03 -->Bar\n<!-- date: 2021-04 \
-                    -->\nTest5\nTest6\nTest7\n<!-- date: \n\n2021-05 -->\nTest8
+        let text = "Test1\nAs of Jan 2021\nTest2\nAs of Feb 2021 \
+                    \nTest3\nTest4\nAs of march 2021Bar\nas of apr 2021 \
+                    \nTest5\nTest6\nTest7\n\n\nas of may 2021\nTest8
         ";
         assert_eq!(
             collect_dates_from_file(&make_date_regex(), text),

Diff for: src/backend/backend-agnostic.md

@@ -2,7 +2,7 @@
 
 <!-- toc -->
 
-As of <!-- date: 2021-10 --> October 2021, `rustc_codegen_ssa` provides an
+As of October 2021, `rustc_codegen_ssa` provides an
 abstract interface for all backends to implement, to allow other codegen
 backends (e.g. [Cranelift]).
 

Diff for: src/borrow_check/region_inference/member_constraints.md

@@ -94,7 +94,7 @@ member constraints come in.
 ## Choices are always lifetime parameters
 
 At present, the "choice" regions from a member constraint are always lifetime
-parameters from the current function. As of <!-- date: 2021-10 --> October 2021,
+parameters from the current function. As of October 2021,
 this falls out from the placement of impl Trait, though in the future it may not
 be the case. We take some advantage of this fact, as it simplifies the current
 code. In particular, we don't have to consider a case like `'0 member of ['1,

Diff for: src/conventions.md

@@ -14,14 +14,14 @@ special config, so this may result in different style from normal [`rustfmt`].
 Therefore, formatting this repository using `cargo fmt` is not recommended.
 
 Instead, formatting should be done using `./x.py fmt`. It's a good habit to run
-`./x.py fmt` before every commit, as this reduces conflicts later. 
+`./x.py fmt` before every commit, as this reduces conflicts later.
 
 Formatting is checked by the `tidy` script. It runs automatically when you do
 `./x.py test` and can be run in isolation with `./x.py fmt --check`.
 
 If you want to use format-on-save in your editor, the pinned version of
 `rustfmt` is built under `build/<target>/stage0/bin/rustfmt`. You'll have to
-pass the <!-- date: 2022-04 --> `--edition=2021` argument yourself when calling
+pass the <!-- as of April 2022 --> `--edition=2021` argument yourself when calling
 `rustfmt` directly.
 
 [fmt]: https://github.com/rust-dev-tools/fmt-rfcs

Diff for: src/crates-io.md

@@ -12,7 +12,7 @@ reasons:
 - The dependency may have transitive dependencies that have one of the above
   problems.
 
-As of <!-- date: 2022-02 --> February 2022, there is no official policy for vetting
+As of February 2022, there is no official policy for vetting
 new dependencies to the compiler. Generally, new dependencies are not added
 to the compiler unless there is a good reason to do so.
 

Diff for: src/diagnostics/diagnostic-items.md

@@ -43,7 +43,7 @@ A new diagnostic item can be added with these two steps:
     For the naming conventions of diagnostic items, please refer to
     [*Naming Conventions*](#naming-conventions).
 
-2. As of <!-- date: 2022-02 --> February 2022, diagnostic items in code are
+2. As of February 2022, diagnostic items in code are
    accessed via symbols in [`rustc_span::symbol::sym`]. To add your newly
    created diagnostic item simply open the module file and add the name (In
    this case `Cat`) at the correct point in the list.

Diff for: src/diagnostics/lintstore.md

@@ -17,7 +17,7 @@ default lint level and other metadata come from. These are normally defined by
 way of the [`declare_lint!`] macro, which boils down to a static with type
 `&rustc_session::lint::Lint`.
 
-As of <!-- date: 2022-02 --> February 2022, we lint against direct declarations
+As of February 2022, we lint against direct declarations
 without the use of the macro today (although this may change in the future, as
 the macro is somewhat unwieldy to add new fields to, like all macros).
 

Diff for: src/diagnostics/translation.md

@@ -217,7 +217,7 @@ returned by `Emitter::fluent_bundle`. This bundle is used preferentially when
 translating messages, the fallback bundle is only used if the primary bundle is
 missing a message or not provided.
 
-As of <!-- date: 2022-06 --> June 2022, there are no locale bundles
+As of June 2022, there are no locale bundles
 distributed with the compiler, but mechanisms are implemented for loading
 bundles.
 

Diff for: src/git.md

@@ -157,7 +157,7 @@ no changes added to commit (use "git add" and/or "git commit -a")
 These changes are not changes to files: they are changes to submodules (more on
 this [later](#git-submodules)). To get rid of those, run `git submodule update`
 (or run any `x.py` command, which will automatically update the submodules).
-Note that there is (as of <!-- date: 2022-02 --> February 2022) a [bug][#77620] if you use
+Note that there is (as of February 2022) a [bug][#77620] if you use
 worktrees, submodules, and `x.py` in a commit hook. If you run into an error
 like:
 

Diff for: src/llvm-coverage-instrumentation.md

@@ -222,8 +222,8 @@ properly-configured variables in LLVM IR, according to very specific
 details of the [_LLVM Coverage Mapping Format_][coverage-mapping-format]
 (Version 6).[^llvm-and-covmap-versions]
 
-[^llvm-and-covmap-versions]: The Rust compiler (as of <!-- date: 2021-12 -->
-December 2021) supports _LLVM Coverage Mapping Format_ Version 5 or 6. Version 5
+[^llvm-and-covmap-versions]: The Rust compiler (as of December 2021)
+supports _LLVM Coverage Mapping Format_ Version 5 or 6. Version 5
 was introduced in _LLVM 12_, which is (as of this writing) the minimum LLVM
 version supported by the current version of Rust. Version 6 was introduced in
 _LLVM 13_, which is currently the default LLVM version for Rust. The Rust

Diff for: src/opaque-types-type-alias-impl-trait.md

@@ -14,9 +14,9 @@ This declares an opaque type named `Foo`, of which the only information is that
 it implements `Bar`. Therefore, any of `Bar`'s interface can be used on a `Foo`,
 but nothing else (regardless of whether it implements any other traits).
 
-Since there needs to be a concrete background type, you can (as of <!-- date:
-2021-01 --> January 2021) express that type by using the opaque type in a
-"defining use site".
+Since there needs to be a concrete background type,
+you can (as of January 2021) express that type
+by using the opaque type in a "defining use site".
 
 ```rust,ignore
 struct Struct;

Diff for: src/overview.md

@@ -292,7 +292,7 @@ Moreover, the compiler wasn't originally built to use a query system; the query
 system has been retrofitted into the compiler, so parts of it are not query-fied
 yet. Also, LLVM isn't our code, so that isn't querified either. The plan is to
 eventually query-fy all of the steps listed in the previous section,
-but as of <!-- date: 2021-11 --> November 2021, only the steps between HIR and
+but as of November 2021, only the steps between HIR and
 LLVM IR are query-fied. That is, lexing, parsing, name resolution, and macro
 expansion are done all at once for the whole program.
 

Diff for: src/parallel-rustc.md

@@ -1,6 +1,6 @@
 # Parallel Compilation
 
-As of <!-- date: 2022-05 --> May 2022, The only stage of the compiler
+As of May 2022, The only stage of the compiler
 that is already parallel is codegen. The nightly compiler implements query evaluation,
 but there is still a lot of work to be done. The lack of parallelism at other stages
 also represents an opportunity for improving compiler performance. One can try out the current
@@ -60,7 +60,7 @@ this issue can be found [here][parallel-rustdoc].
 
 ## Current Status
 
-As of <!-- date: 2022-05 --> May 2022, work on explicitly parallelizing the
+As of May 2022, work on explicitly parallelizing the
 compiler has stalled. There is a lot of design and correctness work that needs
 to be done.
 
@@ -76,7 +76,7 @@ These are the basic ideas in the effort to make `rustc` parallel:
 
 [`rayon`]: https://crates.io/crates/rayon
 
-As of <!-- date: 2022-05 --> May 2022, much of this effort is on hold due
+As of May 2022, much of this effort is on hold due
 to lack of manpower. We have a working prototype with promising performance
 gains in many cases. However, there are two blockers:
 

Diff for: src/profiling.md

@@ -108,6 +108,6 @@ The llvm-lines output is affected by several options.
 
 MIR optimizations have little impact. Compared to the default `RUSTFLAGS="-Z
 mir-opt-level=1"`, level 0 adds 0.3GB and level 2 removes 0.2GB.
-As of <!-- date: 2022-07 --> July 2022,
+As of July 2022,
 inlining happens in LLVM and GCC codegen backends,
 missing only in the Cranelift one.

Diff for: src/queries/query-evaluation-model-in-detail.md

@@ -76,7 +76,7 @@ executed, no results are cached. But the context already provides access to
 "input" data, i.e. pieces of immutable data that were computed before the
 context was created and that queries can access to do their computations.
 
-As of <!-- date: 2021-01 --> January 2021, this input data consists mainly of
+As of January 2021, this input data consists mainly of
 the HIR map, upstream crate metadata, and the command-line options the compiler
 was invoked with; but in the future inputs will just consist of command-line
 options and a list of source files -- the HIR map will itself be provided by a

Diff for: src/query.md

@@ -3,7 +3,7 @@
 <!-- toc -->
 
 As described in [the high-level overview of the compiler][hl], the Rust compiler
-is still (as of <!-- date: 2021-07 --> July 2021) transitioning from a
+is still (as of July 2021) transitioning from a
 traditional "pass-based" setup to a "demand-driven" system. The compiler query
 system is the key to rustc's demand-driven organization.
 The idea is pretty simple. Instead of entirely independent passes

Diff for: src/rustc-driver-getting-diagnostics.md

@@ -7,7 +7,7 @@
 To get diagnostics from the compiler,
 configure `rustc_interface::Config` to output diagnostic to a buffer,
 and run `TyCtxt.analysis`. The following was tested
-with <!-- date: 2022-06 --> `nightly-2022-06-05` (See [here][example]
+with <!-- as of June 2022 --> `nightly-2022-06-05` (See [here][example]
 for the complete example):
 
 [example]: https://github.com/rust-lang/rustc-dev-guide/blob/master/examples/rustc-driver-getting-diagnostics.rs

Diff for: src/rustc-driver-interacting-with-the-ast.md

@@ -5,7 +5,7 @@
 ## Getting the type of an expression
 
 To get the type of an expression, use the `global_ctxt` to get a `TyCtxt`.
-The following was tested with <!-- date: 2022-06 --> `nightly-2022-06-05`
+The following was tested with <!-- as of June 2022 --> `nightly-2022-06-05`
 (see [here][example] for the complete example):
 
 [example]: https://github.com/rust-lang/rustc-dev-guide/blob/master/examples/rustc-driver-interacting-with-the-ast.rs

Diff for: src/rustdoc-internals.md

@@ -66,7 +66,7 @@ these passes, please let us know!)
 
 [44136]: https://github.com/rust-lang/rust/issues/44136
 
-Here is the list of passes as of <!-- date: 2022-05 --> May 2022:
+Here is the list of passes as of May 2022:
 
 - `calculate-doc-coverage` calculates information used for the `--show-coverage`
   flag.

Diff for: src/salsa.md

@@ -9,7 +9,7 @@ want to watch [Salsa In More
 Depth](https://www.youtube.com/watch?v=i_IhACacPRY), also by Niko
 Matsakis.
 
-> As of <!-- date: 2022-04 --> April 2022, although Salsa is inspired by
+> As of April 2022, although Salsa is inspired by
 > (among other things) rustc's query system, it is not used directly in rustc.
 > It _is_ used in chalk and extensively in `rust-analyzer`, but there are no
 > medium or long-term concrete plans to integrate it into the compiler.

Diff for: src/tests/compiletest.md

@@ -452,7 +452,7 @@ fn main() {
 
 ## Revisions
 
-Certain classes of tests support "revisions" (as of <!-- date: 2022-07 --> July 2022,
+Certain classes of tests support "revisions" (as of July 2022,
 this includes UI, assembly, codegen, debuginfo, incremental, and rustdoc UI tests,
 though incremental tests are somewhat different).
 Revisions allow a single test file to be used for multiple tests.

Diff for: src/the-parser.md

@@ -1,6 +1,6 @@
 # Lexing and Parsing
 
-As of <!-- date: 2021-01 --> January 2021, the lexer and parser are undergoing
+As of January 2021, the lexer and parser are undergoing
 refactoring to allow extracting them into libraries.
 
 The very first thing the compiler does is take the program (in Unicode

Diff for: src/thir.md

@@ -4,7 +4,7 @@
 
 The THIR ("Typed High-Level Intermediate Representation"), previously called HAIR for
 "High-Level Abstract IR", is another IR used by rustc that is generated after
-[type checking]. It is (as of <!-- date: 2022-04 --> April 2022) only used for
+[type checking]. It is (as of April 2022) only used for
 [MIR construction] and [exhaustiveness checking]. There is also
 [an experimental unsafety checker][thir-unsafeck] that operates on the THIR as a replacement for
 the current MIR unsafety checker, and can be used instead of the MIR unsafety checker by passing

Diff for: src/traits/chalk.md

@@ -1,7 +1,7 @@
 # Chalk-based trait solving
 
-[Chalk][chalk] is an experimental trait solver for Rust that is (as of <!--
-date: 2022-05 --> May 2022) under development by the [Types team].
+[Chalk][chalk] is an experimental trait solver for Rust that is
+(as of May 2022) under development by the [Types team].
 Its goal is to enable a lot of trait system features and bug fixes
 that are hard to implement (e.g. GATs or specialization). If you would like to
 help in hacking on the new solver, drop by on the rust-lang Zulip in the [`#t-types`]

Diff for: src/traits/resolution.md

@@ -120,7 +120,7 @@ the obligation contains unbound inference variables.
 
 The subroutines that decide whether a particular impl/where-clause/etc applies
 to a particular obligation are collectively referred to as the process of
-_matching_. As of <!-- date: 2022-05 --> May 2022, this amounts to unifying
+_matching_. As of May 2022, this amounts to unifying
 the `Self` types, but in the future we may also recursively consider some of the
 nested obligations, in the case of an impl.
 

Diff for: src/type-inference.md

@@ -72,7 +72,7 @@ inference works, or perhaps this blog post on
 [Unification in the Chalk project]: http://smallcultfollowing.com/babysteps/blog/2017/03/25/unification-in-chalk-part-1/
 
 All told, the inference context stores five kinds of inference variables
-(as of <!-- date: 2021-06 --> June 2021):
+(as of June 2021):
 
 - Type variables, which come in three varieties:
   - General type variables (the most common). These can be unified with any