Rollup merge of #122060 - clubby789:stabilize-imported-main, r=lcnr

Stabilize `imported_main`

FCP: #28937 (comment)
Docs: rust-lang/reference#1461

Author: matthiaskrgr

compiler/rustc_feature/src/accepted.rs

@@ -203,6 +203,8 @@ declare_features! (
     (accepted, impl_header_lifetime_elision, "1.31.0", Some(15872)),
     /// Allows referencing `Self` and projections in impl-trait.
     (accepted, impl_trait_projections, "1.74.0", Some(103532)),
+    /// Allows using imported `main` function
+    (accepted, imported_main, "CURRENT_RUSTC_VERSION", Some(28937)),
     /// Allows using `a..=b` and `..=b` as inclusive range syntaxes.
     (accepted, inclusive_range_syntax, "1.26.0", Some(28237)),
     /// Allows inferring outlives requirements (RFC 2093).

compiler/rustc_feature/src/unstable.rs

@@ -495,8 +495,6 @@ declare_features! (
     (unstable, impl_trait_in_assoc_type, "1.70.0", Some(63063)),
     /// Allows `impl Trait` as output type in `Fn` traits in return position of functions.
     (unstable, impl_trait_in_fn_trait_return, "1.64.0", Some(99697)),
-    /// Allows using imported `main` function
-    (unstable, imported_main, "1.53.0", Some(28937)),
     /// Allows associated types in inherent impls.
     (incomplete, inherent_associated_types, "1.52.0", Some(8995)),
     /// Allow anonymous constants from an inline `const` block

compiler/rustc_passes/src/entry.rs

@@ -7,7 +7,6 @@ use rustc_hir::{ItemId, Node, CRATE_HIR_ID};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{sigpipe, CrateType, EntryFnType};
-use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
 
@@ -133,16 +132,6 @@ fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) -> Option<(DefId,
                 return None;
             }
 
-            if main_def.is_import && !tcx.features().imported_main {
-                let span = main_def.span;
-                feature_err(
-                    &tcx.sess,
-                    sym::imported_main,
-                    span,
-                    "using an imported function as entry point `main` is experimental",
-                )
-                .emit();
-            }
             return Some((def_id, EntryFnType::Main { sigpipe: sigpipe(tcx, def_id) }));
         }
         no_main_err(tcx, visitor);

src/tools/miri/test-cargo-miri/tests/main.rs

@@ -1,3 +1 @@
-#![feature(imported_main)]
-
 use cargo_miri_test::main;

src/tools/miri/tests/pass/imported_main.rs

@@ -1,5 +1,3 @@
-#![feature(imported_main)]
-
 pub mod foo {
     pub fn mymain() {
         println!("Hello, world!");

src/tools/miri/tests/pass/main_fn.rs

@@ -1,5 +1,3 @@
-#![feature(imported_main)]
-
 mod foo {
     pub(crate) fn bar() {}
 }

tests/ui/entry-point/imported_main_conflict.rs

@@ -1,5 +1,4 @@
-#![feature(imported_main)]
-//~^ ERROR `main` is ambiguous
+//~ ERROR `main` is ambiguous
 mod m1 { pub(crate) fn main() {} }
 mod m2 { pub(crate) fn main() {} }
 

tests/ui/entry-point/imported_main_conflict.stderr

@@ -2,13 +2,13 @@ error[E0659]: `main` is ambiguous
    |
    = note: ambiguous because of multiple glob imports of a name in the same module
 note: `main` could refer to the function imported here
-  --> $DIR/imported_main_conflict.rs:6:5
+  --> $DIR/imported_main_conflict.rs:5:5
    |
 LL | use m1::*;
    |     ^^^^^
    = help: consider adding an explicit import of `main` to disambiguate
 note: `main` could also refer to the function imported here
-  --> $DIR/imported_main_conflict.rs:7:5
+  --> $DIR/imported_main_conflict.rs:6:5
    |
 LL | use m2::*;
    |     ^^^^^

tests/ui/entry-point/imported_main_const_fn_item_type_forbidden.rs

@@ -1,4 +1,3 @@
-#![feature(imported_main)]
 #![feature(type_alias_impl_trait)]
 #![allow(incomplete_features)]
 pub mod foo {

tests/ui/entry-point/imported_main_const_fn_item_type_forbidden.stderr

@@ -1,5 +1,5 @@
 error[E0601]: `main` function not found in crate `imported_main_const_fn_item_type_forbidden`
-  --> $DIR/imported_main_const_fn_item_type_forbidden.rs:11:22
+  --> $DIR/imported_main_const_fn_item_type_forbidden.rs:10:22
    |
 LL | use foo::BAR as main;
    |     ---------------- ^ consider adding a `main` function to `$DIR/imported_main_const_fn_item_type_forbidden.rs`