build: rework opts and bump toolchain

Cargo.toml

@@ -23,11 +23,24 @@ name = "sudoku_rust"
 path = "src/main.rs"
 
 [profile.release]
-lto = true
+# Configurations explicitly listed here for clarity.
+# Using the best options for performance.
 opt-level = 3
+lto = "fat"
+codegen-units = 1
+strip = "symbols" # Set to `false` for debug information
+debug = false # Set to `true` for debug information
+panic = "abort" # Let it crash and force ourselves to write safe Rust
+
+[profile.release-with-debug]
+inherits = "release"
+strip = false # Keep debug information in binary
+debug = true # Include maximum amount of debug information
 
 [profile.dev]
-opt-level = "s"
+# Disabling debug info speeds up local and CI builds,
+# and we don't rely on it for debugging that much.
+debug = false
 
 [[bench]]
 name = "sudoku_benchmarks"

rust-toolchain.toml

@@ -2,4 +2,4 @@
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 # https://rust-lang.github.io/rustup/concepts/profiles.html
 profile = "default"
-channel = "1.81"
+channel = "1.82"