Auto merge of #125645 - RalfJung:unclear_local_imports, r=nnethercote

add unqualified_local_imports lint

This lint helps deal with rust-lang/rustfmt#4709 by having the compiler detect imports of local items that are not syntactically distinguishable from imports from other cates. Making them  syntactically distinguishable ensures rustfmt can consistently apply the desired import grouping.

Author: bors

src/borrow_tracker/stacked_borrows/mod.rs

@@ -22,9 +22,9 @@ use crate::borrow_tracker::{
 use crate::concurrency::data_race::{NaReadType, NaWriteType};
 use crate::*;
 
-use diagnostics::{RetagCause, RetagInfo};
-pub use item::{Item, Permission};
-pub use stack::Stack;
+use self::diagnostics::{RetagCause, RetagInfo};
+pub use self::item::{Item, Permission};
+pub use self::stack::Stack;
 
 pub type AllocState = Stacks;
 

src/borrow_tracker/tree_borrows/mod.rs

@@ -19,8 +19,8 @@ mod unimap;
 #[cfg(test)]
 mod exhaustive;
 
-use perms::Permission;
-pub use tree::Tree;
+use self::perms::Permission;
+pub use self::tree::Tree;
 
 pub type AllocState = Tree;
 

src/borrow_tracker/tree_borrows/perms.rs

@@ -47,7 +47,7 @@ enum PermissionPriv {
     /// rejects: all child accesses (UB).
     Disabled,
 }
-use PermissionPriv::*;
+use self::PermissionPriv::*;
 
 impl PartialOrd for PermissionPriv {
     /// PermissionPriv is ordered by the reflexive transitive closure of

src/concurrency/mod.rs

@@ -7,4 +7,4 @@ pub mod thread;
 mod vector_clock;
 pub mod weak_memory;
 
-pub use vector_clock::VClock;
+pub use self::vector_clock::VClock;

src/intrinsics/atomic.rs

@@ -1,7 +1,7 @@
 use rustc_middle::{mir, mir::BinOp, ty};
 
 use crate::*;
-use helpers::check_arg_count;
+use self::helpers::check_arg_count;
 
 pub enum AtomicOp {
     /// The `bool` indicates whether the result of the operation should be negated (`UnOp::Not`,

src/intrinsics/mod.rs

@@ -13,9 +13,9 @@ use rustc_span::{Symbol, sym};
 use rustc_target::abi::Size;
 
 use crate::*;
-use atomic::EvalContextExt as _;
-use helpers::{ToHost, ToSoft, check_arg_count};
-use simd::EvalContextExt as _;
+use self::atomic::EvalContextExt as _;
+use self::helpers::{ToHost, ToSoft, check_arg_count};
+use self::simd::EvalContextExt as _;
 
 impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
 pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {

src/lib.rs

@@ -51,6 +51,8 @@
     clippy::cast_lossless,
     clippy::cast_possible_truncation,
 )]
+#![cfg_attr(not(bootstrap), feature(unqualified_local_imports))]
+#![cfg_attr(not(bootstrap), warn(unqualified_local_imports))]
 // Needed for rustdoc from bootstrap (with `-Znormalize-docs`).
 #![recursion_limit = "256"]
 

src/shims/env.rs

@@ -3,7 +3,7 @@ use std::ffi::{OsStr, OsString};
 use rustc_data_structures::fx::FxHashMap;
 
 use crate::*;
-use shims::{unix::UnixEnvVars, windows::WindowsEnvVars};
+use self::shims::{unix::UnixEnvVars, windows::WindowsEnvVars};
 
 #[derive(Default)]
 pub enum EnvVars<'tcx> {

src/shims/foreign_items.rs

@@ -15,7 +15,7 @@ use rustc_target::{
 use super::alloc::EvalContextExt as _;
 use super::backtrace::EvalContextExt as _;
 use crate::*;
-use helpers::{ToHost, ToSoft};
+use self::helpers::{ToHost, ToSoft};
 
 /// Type of dynamic symbols (for `dlsym` et al)
 #[derive(Debug, Copy, Clone)]

src/shims/mod.rs

@@ -17,7 +17,7 @@ pub mod panic;
 pub mod time;
 pub mod tls;
 
-pub use unix::{DirTable, EpollInterestTable, FdTable};
+pub use self::unix::{DirTable, EpollInterestTable, FdTable};
 
 /// What needs to be done after emulating an item (a shim or an intrinsic) is done.
 pub enum EmulateItemResult {