Merge branch 'kevinmehall:master' into patch-unstable-vectors

.github/workflows/rust.yml

@@ -9,11 +9,20 @@ env:
 
 jobs:
   build:
+    name: Rust ${{matrix.rust}}
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: [stable, 1.68.0]
 
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+    - uses: dtolnay/rust-toolchain@master
+      with:
+        toolchain: ${{matrix.rust}}
+        components: rustfmt
     - name: Check bootstrap
       run: ./bootstrap.sh && git diff --exit-code
     - name: Run tests

Cargo.toml

@@ -12,6 +12,7 @@ keywords = ["peg", "parser", "parsing", "grammar"]
 categories = ["parsing"]
 readme = "README.md"
 edition = "2018"
+rust-version = "1.68.0" # if changed, also update .github/workflows/rust.yml
 
 [dependencies]
 peg-macros = { path = "./peg-macros", version = "= 0.8.1" }
@@ -22,6 +23,7 @@ arrayvec = "0.7.2"
 assert_matches = "1.5.0"
 smallvec = "1.10.0"
 trybuild = "1.0.80"
+version_check = "0.9"
 
 [[test]]
 name = "trybuild"

README.md

@@ -60,11 +60,13 @@ pub fn main() {
 [annotate-snippets]: https://crates.io/crates/annotate-snippets
 [codespan-reporting]: https://crates.io/crates/codespan-reporting
 [codemap-diagnostic]: https://crates.io/crates/codemap-diagnostic
+
 ## Development
 
 The `rust-peg` grammar is written in `rust-peg`: `peg-macros/grammar.rustpeg`. To avoid the circular dependency, a precompiled grammar is checked in as `peg-macros/grammar.rs`. To regenerate this, run the `./bootstrap.sh` script.
 
-There is a large test suite which uses [`trybuild`](https://crates.io/crates/trybuild) to support testing for compilation failure errors.
+There is a large test suite which uses [`trybuild`](https://crates.io/crates/trybuild) to test both functionality (`tests/run-pass`) and error messages for incorrect grammars (`tests/compile-fail`). Because `rustc` error messages change, the `compile-fail` tests are only run on the minimum supported Rust version to avoid spurious failures.
+
 Use `cargo test` to run the entire suite,
 or `cargo test -- trybuild trybuild=lifetimes.rs` to test just the indicated file.
 Add `--features trace` to trace these tests.

src/lib.rs

@@ -157,7 +157,7 @@
 //! ### Repeat ranges
 //!
 //! The repeat operators `*` and `**` can be followed by an optional range specification of the
-//! form `<n>` (exact), `<n,>` (min), `<,m>` (max) or `<n,m>` (range), where `n` and `m` are either
+//! form `<n>` (exact), `<n,>` (min-inclusive), `<,m>` (max-inclusive) or `<n,m>` (range-inclusive), where `n` and `m` are either
 //! integers, or a Rust `usize` expression enclosed in `{}`.
 //!
 //! ### Precedence climbing

tests/trybuild.rs

@@ -1,20 +1,26 @@
-extern crate trybuild;
-
 fn main() {
+    let args: Vec<_> = std::env::args().collect();
     let t = trybuild::TestCases::new();
 
-    let rust_ver = option_env!("TRAVIS_RUST_VERSION");
-    if rust_ver.is_none() {
-        println!(
-            "Note: compile-fail tests are normally only tested on the stable rust compiler in CI."
-        );
-    }
+    t.pass("tests/run-pass/*.rs");
+
+    let expected_rust_ver = env!("CARGO_PKG_RUST_VERSION");
+    let run_anyway = args.iter().any(|a| a == "--compile-fail");
 
-    if rust_ver.is_none() || rust_ver == Some("stable") {
+    let run_compile_fail = run_anyway || version_check::is_exact_version(expected_rust_ver).unwrap_or(true);
+    if run_compile_fail {
         t.compile_fail("tests/compile-fail/*.rs");
-    } else {
-        println!("Skipping compile-fail tests.");
     }
 
-    t.pass("tests/run-pass/*.rs");
+    // Trybuild runs the configured tests on drop
+    drop(t);
+
+    if !run_compile_fail {
+        eprintln!("!!! Skipped compile-fail tests !!!");
+        eprintln!("These tests are only checked on rust version {expected_rust_ver} because");
+        eprintln!("the error message text may change between compiler versions.");
+        eprintln!("");
+        eprintln!("Run `cargo +{expected_rust_ver} test` to run these tests.");
+        eprintln!("");
+    }
 }