Auto merge of #120496 - GuillaumeGomez:rollup-fmu9jre, r=GuillaumeGomez

Rollup of 11 pull requests

Successful merges:

 - #117906 (Improve display of crate name when hovered)
 - #118533 (Suppress unhelpful diagnostics for unresolved top level attributes)
 - #120293 (Deduplicate more sized errors on call exprs)
 - #120295 (Remove `raw_os_nonzero` feature.)
 - #120310 (adapt test for v0 symbol mangling)
 - #120342 (Remove various `has_errors` or `err_count` uses)
 - #120434 (Revert outdated version of "Add the wasm32-wasi-preview2 target")
 - #120445 (Fix some `Arc` allocator leaks)
 - #120475 (Improve error message when `cargo build` is used to build the compiler)
 - #120476 (Remove some unnecessary check logic for lang items in HIR typeck)
 - #120485 (add missing potential_query_instability for keys and values in hashmap)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 16 insertions, 0 deletions

diff --git a/compiler/rustc_macros/build.rs b/compiler/rustc_macros/build.rs
new file mode 100644
index 00000000000..717f8a92245
--- /dev/null
+++ b/compiler/rustc_macros/build.rs
@@ -0,0 +1,16 @@
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-env-changed=RUSTC_BOOTSTRAP");
+    if !std::env::var("RUSTC_BOOTSTRAP").is_ok() {
+        eprintln!(
+            "error: you are attempting to build the compiler without going through bootstrap"
+        );
+        eprintln!(
+            "help: see https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html for how to build the compiler"
+        );
+        eprintln!(
+            "help: if you know what you're doing, set the RUSTC_BOOTSTRAP environment variable to any value"
+        );
+        panic!("wrong command used for building");
+    }
+}