[test] Migrate from trybuild to ui-test

Closes #187

gherrit-pr-id: Gbc6b00b4dee88c0d25be0b277998861157eccda7

Author: joshlf

Cargo.lock

@@ -10,8 +10,13 @@
 # paths that are stable regardless of the path to the repository root. This
 # avoids issues like:
 # https://github.com/dtolnay/trybuild/issues/207#issuecomment-131227.594
-[workspace]
+[[test]]
+name = "ui"
+path = "tests/ui.rs"
+harness = false
 
+[workspace]
+members = []
 [package]
 edition = "2021"
 name = "zerocopy"
@@ -128,10 +133,5 @@ rand = { version = "0.8.5", default-features = false, features = ["small_rng"] }
 rustversion = "1.0"
 static_assertions = "1.1"
 testutil = { path = "testutil" }
-# Pinned to a specific version so that the version used for local development
-# and the version used in CI are guaranteed to be the same. Future versions
-# sometimes change the output format slightly, so a version mismatch can cause
-# CI test failures.
-trybuild = { version = "=1.0.89", features = ["diff"] }
 # In tests, unlike in production, zerocopy-derive is not optional
 zerocopy-derive = { version = "=0.8.38", path = "zerocopy-derive" }

Cargo.toml

@@ -15,4 +15,11 @@ if [[ -z $files ]]
 then
 	exit 1
 fi
-./cargo.sh +nightly fmt --check -- $files >&2
+
+if [[ "$1" == "--fix" ]]; then
+    FMT_FLAGS=""
+else
+    FMT_FLAGS="--check"
+fi
+
+./cargo.sh +nightly fmt $FMT_FLAGS -- $files >&2

ci/check_fmt.sh

@@ -23,8 +23,16 @@ for dir in "${DIRS[@]}"; do
 
     # Find all .stderr files
     while IFS= read -r -d '' stderr_file; do
+        # Strip .stderr extension
+        base="${stderr_file%.stderr}"
+
+        # Strip toolchain suffixes
+        base="${base%.msrv}"
+        base="${base%.stable}"
+        base="${base%.nightly}"
+
         # Construct the corresponding .rs file path
-        rs_file="${stderr_file%.stderr}.rs"
+        rs_file="${base}.rs"
 
         # Check if the .rs file exists. The `-e` flag checks if file exists:
         # It returns true for regular files and valid symlinks, and false for