Rollup merge of rust-lang#157479 - JonathanBrouwer:macro-use-root, r=Kivooeo

Warn when `#[macro_use]` or `#[macro_escape]` is used on the crate root

Fixes rust-lang#157250

Author: jhpratt

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -35,7 +35,6 @@ const MACRO_USE_TEMPLATE: AttributeTemplate = template!(
 const MACRO_USE_ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
     Allow(Target::Mod),
     Allow(Target::ExternCrate),
-    Allow(Target::Crate),
     Error(Target::WherePredicate),
 ]);
 

tests/ui/attributes/attr-on-mac-call.stderr

@@ -173,7 +173,7 @@ warning: `#[macro_use]` attribute cannot be used on macro calls
 LL |     #[macro_use]
    |     ^^^^^^^^^^^^
    |
-   = help: `#[macro_use]` can be applied to crates, extern crates, and modules
+   = help: `#[macro_use]` can be applied to extern crates and modules
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 warning: `#[must_use]` attribute cannot be used on macro calls

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -42,7 +42,10 @@
 #![allow(x5300)] //~ WARN unknown lint: `x5300`
 #![forbid(x5200)] //~ WARN unknown lint: `x5200`
 #![deny(x5100)] //~ WARN unknown lint: `x5100`
-#![macro_use] // (allowed if no argument; see issue-43160-gating-of-macro_use.rs)
+#![macro_use] //~ WARN attribute cannot be used on
+//~| WARN previously accepted
+//~| HELP can be applied to
+//~| HELP remove the attribute
 // skipping testing of cfg
 // skipping testing of cfg_attr
 #![should_panic] //~ WARN attribute cannot be used on