Remove uses of box_syntax in rustc and tools

Author: clubby789

compiler/rustc_codegen_cranelift/example/alloc_example.rs

@@ -1,4 +1,4 @@
-#![feature(start, core_intrinsics, alloc_error_handler, box_syntax)]
+#![feature(start, core_intrinsics, alloc_error_handler)]
 #![no_std]
 
 extern crate alloc;
@@ -29,7 +29,7 @@ fn alloc_error_handler(_: alloc::alloc::Layout) -> ! {
 
 #[start]
 fn main(_argc: isize, _argv: *const *const u8) -> isize {
-    let world: Box<&str> = box "Hello World!\0";
+    let world: Box<&str> = Box::new("Hello World!\0");
     unsafe {
         puts(*world as *const str as *const u8);
     }

compiler/rustc_codegen_cranelift/example/mini_core_hello_world.rs

@@ -1,4 +1,4 @@
-#![feature(no_core, lang_items, never_type, linkage, extern_types, thread_local, box_syntax)]
+#![feature(no_core, lang_items, never_type, linkage, extern_types, thread_local)]
 #![no_core]
 #![allow(dead_code, non_camel_case_types)]
 
@@ -178,7 +178,7 @@ fn main() {
         let ptr: *const i8 = hello as *const [u8] as *const i8;
         puts(ptr);
 
-        let world: Box<&str> = box "World!\0";
+        let world: Box<&str> = Box::new("World!\0");
         puts(*world as *const str as *const i8);
         world as Box<dyn SomeTrait>;
 
@@ -238,10 +238,10 @@ fn main() {
         }
     }
 
-    let _ = box NoisyDrop {
+    let _ = Box::new(NoisyDrop {
         text: "Boxed outer got dropped!\0",
         inner: NoisyDropInner,
-    } as Box<dyn SomeTrait>;
+    }) as Box<dyn SomeTrait>;
 
     const FUNC_REF: Option<fn()> = Some(main);
     match FUNC_REF {

compiler/rustc_codegen_gcc/example/alloc_example.rs

@@ -1,4 +1,4 @@
-#![feature(start, box_syntax, core_intrinsics, alloc_error_handler, lang_items)]
+#![feature(start, core_intrinsics, alloc_error_handler, lang_items)]
 #![no_std]
 
 extern crate alloc;
@@ -38,7 +38,7 @@ unsafe extern "C" fn _Unwind_Resume() {
 
 #[start]
 fn main(_argc: isize, _argv: *const *const u8) -> isize {
-    let world: Box<&str> = box "Hello World!\0";
+    let world: Box<&str> = Box::new("Hello World!\0");
     unsafe {
         puts(*world as *const str as *const u8);
     }

compiler/rustc_codegen_gcc/example/mini_core_hello_world.rs

@@ -1,7 +1,7 @@
 // Adapted from https://github.com/sunfishcode/mir2cranelift/blob/master/rust-examples/nocore-hello-world.rs
 
 #![feature(
-    no_core, unboxed_closures, start, lang_items, box_syntax, never_type, linkage,
+    no_core, unboxed_closures, start, lang_items, never_type, linkage,
     extern_types, thread_local
 )]
 #![no_core]
@@ -163,7 +163,7 @@ fn main() {
         let ptr: *const u8 = hello as *const [u8] as *const u8;
         puts(ptr);
 
-        let world: Box<&str> = box "World!\0";
+        let world: Box<&str> = Box::new("World!\0");
         puts(*world as *const str as *const u8);
         world as Box<dyn SomeTrait>;
 
@@ -223,10 +223,10 @@ fn main() {
         }
     }
 
-    let _ = box NoisyDrop {
+    let _ = Box::new(NoisyDrop {
         text: "Boxed outer got dropped!\0",
         inner: NoisyDropInner,
-    } as Box<dyn SomeTrait>;
+    }) as Box<dyn SomeTrait>;
 
     const FUNC_REF: Option<fn()> = Some(main);
     #[allow(unreachable_code)]

compiler/rustc_codegen_gcc/example/mod_bench.rs

@@ -1,4 +1,4 @@
-#![feature(start, box_syntax, core_intrinsics, lang_items)]
+#![feature(start, core_intrinsics, lang_items)]
 #![no_std]
 
 #[link(name = "c")]

compiler/rustc_error_codes/src/error_codes/E0010.md

@@ -5,7 +5,5 @@ the heap at runtime, and therefore cannot be done at compile time.
 Erroneous code example:
 
 ```compile_fail,E0010
-#![feature(box_syntax)]
-
-const CON : Box<i32> = box 0;
+const CON : Vec<i32> = vec![1, 2, 3];
 ```

compiler/rustc_hir_pretty/src/lib.rs

@@ -1367,8 +1367,8 @@ impl<'a> State<'a> {
         self.ann.pre(self, AnnNode::Expr(expr));
         match expr.kind {
             hir::ExprKind::Box(expr) => {
-                self.word_space("box");
-                self.print_expr_maybe_paren(expr, parser::PREC_PREFIX);
+                self.word_space("Box::new");
+                self.print_call_post(std::slice::from_ref(expr));
             }
             hir::ExprKind::Array(exprs) => {
                 self.print_expr_vec(exprs);

compiler/rustc_lint/src/unused.rs

@@ -1371,7 +1371,6 @@ declare_lint_pass!(UnusedAllocation => [UNUSED_ALLOCATION]);
 impl<'tcx> LateLintPass<'tcx> for UnusedAllocation {
     fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) {
         match e.kind {
-            hir::ExprKind::Box(_) => {}
             hir::ExprKind::Call(path_expr, [_])
                 if let hir::ExprKind::Path(qpath) = &path_expr.kind
                 && let Some(did) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id()

compiler/rustc_mir_transform/src/large_enums.rs

@@ -158,10 +158,12 @@ impl EnumSizeOpt {
                             tmp_ty,
                         ),
                     };
-                    let rval = Rvalue::Use(Operand::Constant(box (constant_vals)));
+                    let rval = Rvalue::Use(Operand::Constant(Box::new(constant_vals)));
 
-                    let const_assign =
-                        Statement { source_info, kind: StatementKind::Assign(box (place, rval)) };
+                    let const_assign = Statement {
+                        source_info,
+                        kind: StatementKind::Assign(Box::new((place, rval))),
+                    };
 
                     let discr_place = Place::from(
                         local_decls
@@ -170,48 +172,51 @@ impl EnumSizeOpt {
 
                     let store_discr = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (discr_place, Rvalue::Discriminant(*rhs))),
+                        kind: StatementKind::Assign(Box::new((
+                            discr_place,
+                            Rvalue::Discriminant(*rhs),
+                        ))),
                     };
 
                     let discr_cast_place =
                         Place::from(local_decls.push(LocalDecl::new(tcx.types.usize, span)));
 
                     let cast_discr = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             discr_cast_place,
                             Rvalue::Cast(
                                 CastKind::IntToInt,
                                 Operand::Copy(discr_place),
                                 tcx.types.usize,
                             ),
-                        )),
+                        ))),
                     };
 
                     let size_place =
                         Place::from(local_decls.push(LocalDecl::new(tcx.types.usize, span)));
 
                     let store_size = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             size_place,
                             Rvalue::Use(Operand::Copy(Place {
                                 local: size_array_local,
                                 projection: tcx
                                     .mk_place_elems(&[PlaceElem::Index(discr_cast_place.local)]),
                             })),
-                        )),
+                        ))),
                     };
 
                     let dst =
                         Place::from(local_decls.push(LocalDecl::new(tcx.mk_mut_ptr(ty), span)));
 
                     let dst_ptr = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             dst,
                             Rvalue::AddressOf(Mutability::Mut, *lhs),
-                        )),
+                        ))),
                     };
 
                     let dst_cast_ty = tcx.mk_mut_ptr(tcx.types.u8);
@@ -220,21 +225,21 @@ impl EnumSizeOpt {
 
                     let dst_cast = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             dst_cast_place,
                             Rvalue::Cast(CastKind::PtrToPtr, Operand::Copy(dst), dst_cast_ty),
-                        )),
+                        ))),
                     };
 
                     let src =
                         Place::from(local_decls.push(LocalDecl::new(tcx.mk_imm_ptr(ty), span)));
 
                     let src_ptr = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             src,
                             Rvalue::AddressOf(Mutability::Not, *rhs),
-                        )),
+                        ))),
                     };
 
                     let src_cast_ty = tcx.mk_imm_ptr(tcx.types.u8);
@@ -243,24 +248,24 @@ impl EnumSizeOpt {
 
                     let src_cast = Statement {
                         source_info,
-                        kind: StatementKind::Assign(box (
+                        kind: StatementKind::Assign(Box::new((
                             src_cast_place,
                             Rvalue::Cast(CastKind::PtrToPtr, Operand::Copy(src), src_cast_ty),
-                        )),
+                        ))),
                     };
 
                     let deinit_old =
-                        Statement { source_info, kind: StatementKind::Deinit(box dst) };
+                        Statement { source_info, kind: StatementKind::Deinit(Box::new(dst)) };
 
                     let copy_bytes = Statement {
                         source_info,
-                        kind: StatementKind::Intrinsic(
-                            box NonDivergingIntrinsic::CopyNonOverlapping(CopyNonOverlapping {
+                        kind: StatementKind::Intrinsic(Box::new(
+                            NonDivergingIntrinsic::CopyNonOverlapping(CopyNonOverlapping {
                                 src: Operand::Copy(src_cast_place),
                                 dst: Operand::Copy(dst_cast_place),
                                 count: Operand::Copy(size_place),
                             }),
-                        ),
+                        )),
                     };
 
                     let store_dead = Statement {

compiler/rustc_mir_transform/src/lib.rs

@@ -1,7 +1,6 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(drain_filter)]
-#![feature(box_syntax)]
 #![feature(let_chains)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]

src/doc/unstable-book/src/the-unstable-book.md

@@ -5,16 +5,31 @@ each one organized by a "feature flag." That is, when using an unstable
 feature of Rust, you must use a flag, like this:
 
 ```rust
-#![feature(box_syntax)]
+#![feature(generators, generator_trait)]
+
+use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
 
 fn main() {
-    let five = box 5;
+    let mut generator = || {
+        yield 1;
+        return "foo"
+    };
+
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Yielded(1) => {}
+        _ => panic!("unexpected value from resume"),
+    }
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Complete("foo") => {}
+        _ => panic!("unexpected value from resume"),
+    }
 }
 ```
 
-The `box_syntax` feature [has a chapter][box] describing how to use it.
+The `generators` feature [has a chapter][generators] describing how to use it.
 
-[box]: language-features/box-syntax.md
+[generators]: language-features/generators.md
 
 Because this documentation relates to unstable features, we make no guarantees
 that what is contained here is accurate or up to date. It's developed on a

src/tools/clippy/tests/ui/boxed_local.rs

@@ -1,4 +1,3 @@
-#![feature(box_syntax)]
 #![feature(lint_reasons)]
 #![allow(
     clippy::borrowed_box,
@@ -34,7 +33,7 @@ fn ok_box_trait(boxed_trait: &Box<dyn Z>) {
 }
 
 fn warn_call() {
-    let x = box A;
+    let x = Box::new(A);
     x.foo();
 }
 
@@ -43,41 +42,41 @@ fn warn_arg(x: Box<A>) {
 }
 
 fn nowarn_closure_arg() {
-    let x = Some(box A);
+    let x = Some(Box::new(A));
     x.map_or((), |x| take_ref(&x));
 }
 
 fn warn_rename_call() {
-    let x = box A;
+    let x = Box::new(A);
 
     let y = x;
     y.foo(); // via autoderef
 }
 
 fn warn_notuse() {
-    let bz = box A;
+    let bz = Box::new(A);
 }
 
 fn warn_pass() {
-    let bz = box A;
+    let bz = Box::new(A);
     take_ref(&bz); // via deref coercion
 }
 
 fn nowarn_return() -> Box<A> {
-    box A // moved out, "escapes"
+    Box::new(A) // moved out, "escapes"
 }
 
 fn nowarn_move() {
-    let bx = box A;
+    let bx = Box::new(A);
     drop(bx) // moved in, "escapes"
 }
 fn nowarn_call() {
-    let bx = box A;
+    let bx = Box::new(A);
     bx.clone(); // method only available to Box, not via autoderef
 }
 
 fn nowarn_pass() {
-    let bx = box A;
+    let bx = Box::new(A);
     take_box(&bx); // fn needs &Box
 }
 
@@ -86,30 +85,20 @@ fn take_ref(x: &A) {}
 
 fn nowarn_ref_take() {
     // false positive, should actually warn
-    let x = box A;
+    let x = Box::new(A);
     let y = &x;
     take_box(y);
 }
 
 fn nowarn_match() {
-    let x = box A; // moved into a match
+    let x = Box::new(A); // moved into a match
     match x {
         y => drop(y),
     }
 }
 
 fn warn_match() {
-    let x = box A;
-    match &x {
-        // not moved
-        y => (),
-    }
-}
-
-fn nowarn_large_array() {
-    // should not warn, is large array
-    // and should not be on stack
-    let x = box [1; 10000];
+    let x = Box::new(A);
     match &x {
         // not moved
         y => (),