rustbuild: allow disabling deny(warnings) for bootstrap

When deny-warnings is not specified or set to true, the behaviour is the same as before.
When deny-warnings is set to false, warnings are now allowed

Fixes #63911

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

src/bootstrap/bin/main.rs

@@ -5,9 +5,6 @@
 //! parent directory, and otherwise documentation can be found throughout the `build`
 //! directory in each respective module.
 
-// NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
-
 use std::env;
 
 use bootstrap::{Config, Build};

src/bootstrap/bin/rustc.rs

@@ -15,9 +15,6 @@
 //! switching compilers for the bootstrap and for build scripts will probably
 //! never get replaced.
 
-// NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
-
 use std::env;
 use std::ffi::OsString;
 use std::io;
@@ -124,8 +121,9 @@ fn main() {
 
     if env::var_os("RUSTC_DENY_WARNINGS").is_some() &&
        env::var_os("RUSTC_EXTERNAL_TOOL").is_none() {
-        // When extending this list, search for `NO-RUSTC-WRAPPER` and add the new lints
-        // there as well, some code doesn't go through this `rustc` wrapper.
+        // When extending this list, add the new lints to the RUSTFLAGS of the
+        // build_bootstrap function of src/bootstrap/bootstrap.py as well as
+        // some code doesn't go through this `rustc` wrapper.
         cmd.arg("-Dwarnings");
         cmd.arg("-Drust_2018_idioms");
         cmd.arg("-Dunused_lifetimes");

src/bootstrap/bin/rustdoc.rs

@@ -2,9 +2,6 @@
 //!
 //! See comments in `src/bootstrap/rustc.rs` for more information.
 
-// NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
-
 use std::env;
 use std::process::Command;
 use std::path::PathBuf;

src/bootstrap/bootstrap.py

@@ -631,6 +631,8 @@ def build_bootstrap(self):
         target_linker = self.get_toml("linker", build_section)
         if target_linker is not None:
             env["RUSTFLAGS"] += "-C linker=" + target_linker + " "
+        if self.get_toml("deny-warnings", "rust") != "false":
+            env["RUSTFLAGS"] += "-Dwarnings -Drust_2018_idioms -Dunused_lifetimes "
 
         env["PATH"] = os.path.join(self.bin_root(), "bin") + \
             os.pathsep + env["PATH"]

src/bootstrap/lib.rs

@@ -103,9 +103,6 @@
 //! More documentation can be found in each respective module below, and you can
 //! also check out the `src/bootstrap/README.md` file for more information.
 
-// NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
-
 #![feature(core_intrinsics)]
 #![feature(drain_filter)]
 

src/build_helper/lib.rs

@@ -1,6 +1,3 @@
-// NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
-
 use std::fs::File;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};