Remove migrate borrowck mode

compiler/rustc_apfloat/src/lib.rs

@@ -33,7 +33,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![no_std]
 #![forbid(unsafe_code)]
-#![feature(nll)]
 
 #[macro_use]
 extern crate alloc;

compiler/rustc_ast/src/lib.rs

@@ -17,7 +17,6 @@
 #![feature(let_chains)]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
-#![feature(nll)]
 #![feature(slice_internals)]
 #![feature(stmt_expr_attributes)]
 #![recursion_limit = "256"]

compiler/rustc_builtin_macros/src/lib.rs

@@ -9,7 +9,6 @@
 #![feature(is_sorted)]
 #![feature(let_chains)]
 #![feature(let_else)]
-#![feature(nll)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![recursion_limit = "256"]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -9,7 +9,6 @@
 #![feature(let_else)]
 #![feature(extern_types)]
 #![feature(once_cell)]
-#![feature(nll)]
 #![feature(iter_intersperse)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]

compiler/rustc_codegen_ssa/src/lib.rs

@@ -3,7 +3,6 @@
 #![feature(try_blocks)]
 #![feature(let_else)]
 #![feature(once_cell)]
-#![feature(nll)]
 #![feature(associated_type_bounds)]
 #![feature(strict_provenance)]
 #![feature(int_roundings)]

compiler/rustc_driver/src/lib.rs

@@ -5,7 +5,6 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(nll)]
 #![feature(let_else)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]

compiler/rustc_error_codes/src/error_codes/E0312.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 Reference's lifetime of borrowed content doesn't match the expected lifetime.
 
 Erroneous code example:
 
-```compile_fail,E0312
+```compile_fail
 pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'static str {
     if maybestr.is_none() {
         "(none)"

compiler/rustc_error_codes/src/error_codes/E0477.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 The type does not fulfill the required lifetime.
 
 Erroneous code example:
 
-```compile_fail,E0477
+```compile_fail
 use std::sync::Mutex;
 
 struct MyString<'a> {

compiler/rustc_error_codes/src/error_codes/E0495.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 A lifetime cannot be determined in the given situation.
 
 Erroneous code example:
 
-```compile_fail,E0495
+```compile_fail
 fn transmute_lifetime<'a, 'b, T>(t: &'a (T,)) -> &'b T {
     match (&t,) { // error!
         ((u,),) => u,

compiler/rustc_error_codes/src/error_codes/E0623.md

@@ -3,39 +3,70 @@ A lifetime didn't match what was expected.
 Erroneous code example:
 
 ```compile_fail,E0623
-struct Foo<'a> {
-    x: &'a isize,
-}
+struct Foo<'a, 'b, T>(std::marker::PhantomData<(&'a (), &'b (), T)>)
+where
+    T: Convert<'a, 'b>;
 
-fn bar<'short, 'long>(c: Foo<'short>, l: &'long isize) {
-    let _: Foo<'long> = c; // error!
+trait Convert<'a, 'b>: Sized {
+    fn cast(&'a self) -> &'b Self;
+}
+impl<'long: 'short, 'short, T> Convert<'long, 'short> for T {
+    fn cast(&'long self) -> &'short T {
+        self
+    }
+}
+// error
+fn badboi<'in_, 'out, T>(
+    x: Foo<'in_, 'out, T>,
+    sadness: &'in_ T
+) -> &'out T {
+    sadness.cast()
 }
 ```
 
 In this example, we tried to set a value with an incompatible lifetime to
-another one (`'long` is unrelated to `'short`). We can solve this issue in
+another one (`'in_` is unrelated to `'out`). We can solve this issue in
 two different ways:
 
-Either we make `'short` live at least as long as `'long`:
+Either we make `'in_` live at least as long as `'out`:
 
 ```
-struct Foo<'a> {
-    x: &'a isize,
-}
+struct Foo<'a, 'b, T>(std::marker::PhantomData<(&'a (), &'b (), T)>)
+where
+    T: Convert<'a, 'b>;
 
-// we set 'short to live at least as long as 'long
-fn bar<'short: 'long, 'long>(c: Foo<'short>, l: &'long isize) {
-    let _: Foo<'long> = c; // ok!
+trait Convert<'a, 'b>: Sized {
+    fn cast(&'a self) -> &'b Self;
+}
+impl<'long: 'short, 'short, T> Convert<'long, 'short> for T {
+    fn cast(&'long self) -> &'short T {
+        self
+    }
+}
+fn badboi<'in_: 'out, 'out, T>(
+    x: Foo<'in_, 'out, T>,
+    sadness: &'in_ T
+) -> &'out T {
+    sadness.cast()
 }
 ```
 
 Or we use only one lifetime:
 
 ```
-struct Foo<'a> {
-    x: &'a isize,
+struct Foo<'a, 'b, T>(std::marker::PhantomData<(&'a (), &'b (), T)>)
+where
+    T: Convert<'a, 'b>;
+
+trait Convert<'a, 'b>: Sized {
+    fn cast(&'a self) -> &'b Self;
+}
+impl<'long: 'short, 'short, T> Convert<'long, 'short> for T {
+    fn cast(&'long self) -> &'short T {
+        self
+    }
 }
-fn bar<'short>(c: Foo<'short>, l: &'short isize) {
-    let _: Foo<'short> = c; // ok!
+fn badboi<'out, T>(x: Foo<'out, 'out, T>, sadness: &'out T) -> &'out T {
+    sadness.cast()
 }
 ```

compiler/rustc_error_codes/src/error_codes/E0713.md

@@ -4,8 +4,6 @@ lifetime of a type that implements the `Drop` trait.
 Erroneous code example:
 
 ```compile_fail,E0713
-#![feature(nll)]
-
 pub struct S<'a> { data: &'a mut String }
 
 impl<'a> Drop for S<'a> {

compiler/rustc_error_codes/src/error_codes/E0759.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 Return type involving a trait did not require `'static` lifetime.
 
 Erroneous code examples:
 
-```compile_fail,E0759
+```compile_fail
 use std::fmt::Debug;
 
 fn foo(x: &i32) -> impl Debug { // error!

compiler/rustc_error_codes/src/error_codes/E0772.md

@@ -1,9 +1,11 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 A trait object has some specific lifetime `'1`, but it was used in a way that
 requires it to have a `'static` lifetime.
 
 Example of erroneous code:
 
-```compile_fail,E0772
+```compile_fail
 trait BooleanLike {}
 trait Person {}
 

compiler/rustc_errors/src/lib.rs

@@ -8,7 +8,6 @@
 #![feature(if_let_guard)]
 #![feature(let_else)]
 #![feature(never_type)]
-#![feature(nll)]
 #![feature(adt_const_params)]
 #![allow(incomplete_features)]
 #![allow(rustc::potential_query_instability)]

compiler/rustc_feature/src/accepted.rs

@@ -221,6 +221,8 @@ declare_features! (
     (accepted, native_link_modifiers, "1.61.0", Some(81490), None),
     /// Allows specifying the whole-archive link modifier
     (accepted, native_link_modifiers_whole_archive, "1.61.0", Some(81490), None),
+    /// Allows using non lexical lifetimes (RFC 2094).
+    (accepted, nll, "1.63.0", Some(43234), None),
     /// Allows using `#![no_std]`.
     (accepted, no_std, "1.6.0", None, None),
     /// Allows defining identifiers beyond ASCII.

compiler/rustc_feature/src/active.rs

@@ -461,8 +461,6 @@ declare_features! (
     (active, never_type, "1.13.0", Some(35121), None),
     /// Allows diverging expressions to fall back to `!` rather than `()`.
     (active, never_type_fallback, "1.41.0", Some(65992), None),
-    /// Allows using non lexical lifetimes (RFC 2094).
-    (active, nll, "1.0.0", Some(43234), None),
     /// Allows `#![no_core]`.
     (active, no_core, "1.3.0", Some(29639), None),
     /// Allows function attribute `#[no_coverage]`, to bypass coverage

compiler/rustc_graphviz/src/lib.rs

@@ -273,7 +273,6 @@
     html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(attr(allow(unused_variables), deny(warnings)))
 )]
-#![feature(nll)]
 
 use LabelText::*;
 

compiler/rustc_incremental/src/lib.rs

@@ -3,7 +3,6 @@
 #![deny(missing_docs)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(let_else)]
-#![feature(nll)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 

compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs

@@ -42,18 +42,7 @@ pub(crate) fn resolve<'tcx>(
             let values = resolver.infer_variable_values(&mut errors);
             (values, errors)
         }
-        RegionckMode::Erase { suppress_errors: false } => {
-            // Do real inference to get errors, then erase the results.
-            let mut values = resolver.infer_variable_values(&mut errors);
-            let re_erased = region_rels.tcx.lifetimes.re_erased;
-
-            values.values.iter_mut().for_each(|v| match *v {
-                VarValue::Value(ref mut r) => *r = re_erased,
-                VarValue::ErrorValue => {}
-            });
-            (values, errors)
-        }
-        RegionckMode::Erase { suppress_errors: true } => {
+        RegionckMode::Erase => {
             // Skip region inference entirely.
             (resolver.erased_data(region_rels.tcx), Vec::new())
         }

compiler/rustc_infer/src/infer/mod.rs

@@ -29,7 +29,6 @@ use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Substs
 pub use rustc_middle::ty::IntVarValue;
 use rustc_middle::ty::{self, GenericParamDefKind, InferConst, Ty, TyCtxt};
 use rustc_middle::ty::{ConstVid, FloatVid, IntVid, TyVid};
-use rustc_session::config::BorrowckMode;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 
@@ -97,29 +96,7 @@ pub enum RegionckMode {
     #[default]
     Solve,
     /// Erase the results of region after solving.
-    Erase {
-        /// A flag that is used to suppress region errors, when we are doing
-        /// region checks that the NLL borrow checker will also do -- it might
-        /// be set to true.
-        suppress_errors: bool,
-    },
-}
-
-impl RegionckMode {
-    /// Indicates that the MIR borrowck will repeat these region
-    /// checks, so we should ignore errors if NLL is (unconditionally)
-    /// enabled.
-    pub fn for_item_body(tcx: TyCtxt<'_>) -> Self {
-        // FIXME(Centril): Once we actually remove `::Migrate` also make
-        // this always `true` and then proceed to eliminate the dead code.
-        match tcx.borrowck_mode() {
-            // If we're on Migrate mode, report AST region errors
-            BorrowckMode::Migrate => RegionckMode::Erase { suppress_errors: false },
-
-            // If we're on MIR, don't report AST region errors as they should be reported by NLL
-            BorrowckMode::Mir => RegionckMode::Erase { suppress_errors: true },
-        }
-    }
+    Erase,
 }
 
 /// This type contains all the things within `InferCtxt` that sit within a

compiler/rustc_interface/src/lib.rs

@@ -2,7 +2,6 @@
 #![feature(let_else)]
 #![feature(internal_output_capture)]
 #![feature(thread_spawn_unchecked)]
-#![feature(nll)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]

compiler/rustc_interface/src/tests.rs

@@ -644,7 +644,6 @@ fn test_debugging_options_tracking_hash() {
     // Make sure that changing an [UNTRACKED] option leaves the hash unchanged.
     // This list is in alphabetical order.
     untracked!(assert_incr_state, Some(String::from("loaded")));
-    untracked!(borrowck, String::from("other"));
     untracked!(deduplicate_diagnostics, false);
     untracked!(dep_tasks, true);
     untracked!(dlltool, Some(PathBuf::from("custom_dlltool.exe")));

compiler/rustc_lint/src/lib.rs

@@ -36,7 +36,6 @@
 #![feature(let_chains)]
 #![feature(let_else)]
 #![feature(never_type)]
-#![feature(nll)]
 #![recursion_limit = "256"]
 
 #[macro_use]

compiler/rustc_llvm/src/lib.rs

@@ -1,4 +1,3 @@
-#![feature(nll)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 
 // NOTE: This crate only exists to allow linking on mingw targets.

compiler/rustc_metadata/src/lib.rs

@@ -6,7 +6,6 @@
 #![feature(iter_from_generator)]
 #![feature(let_chains)]
 #![feature(let_else)]
-#![feature(nll)]
 #![feature(once_cell)]
 #![feature(proc_macro_internals)]
 #![feature(macro_metavar_expr)]

compiler/rustc_middle/src/lib.rs

@@ -39,7 +39,6 @@
 #![feature(never_type)]
 #![feature(extern_types)]
 #![feature(new_uninit)]
-#![feature(nll)]
 #![feature(once_cell)]
 #![feature(let_chains)]
 #![feature(let_else)]