Auto merge of #72935 - Dylan-DPC:rollup-60g3ab6, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #72704 (Remote testing fixes)
 - #72820 (InstCombine: Don't optimize `&mut *x` into `x`)
 - #72848 (Correct generic parameter ordering in error note for E0747)
 - #72902 (Add a test to ensure Fuse stays covariant)
 - #72921 (Add assert to Vec with_capacity docs)

Failed merges:

r? @ghost

src/liballoc/vec.rs

@@ -348,9 +348,11 @@ impl<T> Vec<T> {
     /// for i in 0..10 {
     ///     vec.push(i);
     /// }
+    /// assert_eq!(vec.capacity(), 10);
     ///
     /// // ...but this may make the vector reallocate
     /// vec.push(11);
+    /// assert!(vec.capacity() >= 11);
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]

src/librustc_mir/transform/instcombine.rs

@@ -1,11 +1,12 @@
 //! Performs various peephole optimizations.
 
 use crate::transform::{MirPass, MirSource};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir::Mutability;
 use rustc_index::vec::Idx;
 use rustc_middle::mir::visit::{MutVisitor, Visitor};
 use rustc_middle::mir::{
-    Body, Constant, Local, Location, Mutability, Operand, Place, PlaceRef, ProjectionElem, Rvalue,
+    Body, Constant, Local, Location, Operand, Place, PlaceRef, ProjectionElem, Rvalue,
 };
 use rustc_middle::ty::{self, TyCtxt};
 use std::mem;
@@ -39,7 +40,7 @@ impl<'tcx> MutVisitor<'tcx> for InstCombineVisitor<'tcx> {
     }
 
     fn visit_rvalue(&mut self, rvalue: &mut Rvalue<'tcx>, location: Location) {
-        if let Some(mtbl) = self.optimizations.and_stars.remove(&location) {
+        if self.optimizations.and_stars.remove(&location) {
             debug!("replacing `&*`: {:?}", rvalue);
             let new_place = match rvalue {
                 Rvalue::Ref(_, _, place) => {
@@ -57,10 +58,7 @@ impl<'tcx> MutVisitor<'tcx> for InstCombineVisitor<'tcx> {
                 }
                 _ => bug!("Detected `&*` but didn't find `&*`!"),
             };
-            *rvalue = Rvalue::Use(match mtbl {
+            *rvalue = Rvalue::Use(Operand::Copy(new_place))
-                Mutability::Mut => Operand::Move(new_place),
-                Mutability::Not => Operand::Copy(new_place),
-            });
         }
 
         if let Some(constant) = self.optimizations.arrays_lengths.remove(&location) {
@@ -93,8 +91,8 @@ impl Visitor<'tcx> for OptimizationFinder<'b, 'tcx> {
             {
                 // The dereferenced place must have type `&_`.
                 let ty = Place::ty_from(local, proj_base, self.body, self.tcx).ty;
-                if let ty::Ref(_, _, mtbl) = ty.kind {
+                if let ty::Ref(_, _, Mutability::Not) = ty.kind {
-                    self.optimizations.and_stars.insert(location, mtbl);
+                    self.optimizations.and_stars.insert(location);
                 }
             }
         }
@@ -114,6 +112,6 @@ impl Visitor<'tcx> for OptimizationFinder<'b, 'tcx> {
 
 #[derive(Default)]
 struct OptimizationList<'tcx> {
-    and_stars: FxHashMap<Location, Mutability>,
+    and_stars: FxHashSet<Location>,
     arrays_lengths: FxHashMap<Location, Constant<'tcx>>,
 }

src/librustc_typeck/astconv.rs

@@ -8,6 +8,7 @@
 use crate::collect::PlaceholderHirTyCollector;
 use crate::middle::resolve_lifetime as rl;
 use crate::require_c_abi_if_c_variadic;
+use rustc_ast::ast::ParamKindOrd;
 use rustc_ast::util::lev_distance::find_best_match_for_name;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::ErrorReported;
@@ -483,8 +484,25 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             arg.descr(),
             kind,
         );
+
+        let kind_ord = match kind {
+            "lifetime" => ParamKindOrd::Lifetime,
+            "type" => ParamKindOrd::Type,
+            "constant" => ParamKindOrd::Const,
+            // It's more concise to match on the string representation, though it means
+            // the match is non-exhaustive.
+            _ => bug!("invalid generic parameter kind {}", kind),
+        };
+        let arg_ord = match arg {
+            GenericArg::Lifetime(_) => ParamKindOrd::Lifetime,
+            GenericArg::Type(_) => ParamKindOrd::Type,
+            GenericArg::Const(_) => ParamKindOrd::Const,
+        };
+
         // This note will be true as long as generic parameters are strictly ordered by their kind.
-        err.note(&format!("{} arguments must be provided before {} arguments", kind, arg.descr()));
+        let (first, last) =
+            if kind_ord < arg_ord { (kind, arg.descr()) } else { (arg.descr(), kind) };
+        err.note(&format!("{} arguments must be provided before {} arguments", first, last));
         err.emit();
     }
 

src/test/mir-opt/inline/issue-58867-inline-as-ref-as-mut/rustc.a.Inline.after.mir

@@ -8,6 +8,7 @@ fn a(_1: &mut [T]) -> &mut [T] {
     let mut _4: &mut [T];                // in scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:6
     scope 1 {
         debug self => _4;                // in scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
+        let mut _5: &mut [T];            // in scope 1 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:15
     }
 
     bb0: {
@@ -15,7 +16,10 @@ fn a(_1: &mut [T]) -> &mut [T] {
         StorageLive(_3);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:15
         StorageLive(_4);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:6
         _4 = &mut (*_1);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:6
-        _3 = move _4;                    // scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
+        StorageLive(_5);                 // scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
+        _5 = &mut (*_4);                 // scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
+        _3 = &mut (*_5);                 // scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
+        StorageDead(_5);                 // scope 1 at $SRC_DIR/libcore/convert/mod.rs:LL:COL
         _2 = &mut (*_3);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:15
         StorageDead(_4);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:14: 3:15
         _0 = &mut (*_2);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:3:5: 3:15

src/test/mir-opt/inline/issue-58867-inline-as-ref-as-mut/rustc.b.Inline.after.mir

@@ -9,6 +9,7 @@ fn b(_1: &mut std::boxed::Box<T>) -> &mut T {
     scope 1 {
         debug self => _4;                // in scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
         let mut _5: &mut T;              // in scope 1 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:15
+        let mut _6: &mut T;              // in scope 1 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:15
     }
 
     bb0: {
@@ -17,8 +18,11 @@ fn b(_1: &mut std::boxed::Box<T>) -> &mut T {
         StorageLive(_4);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:6
         _4 = &mut (*_1);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:6
         StorageLive(_5);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
-        _5 = &mut (*(*_4));              // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
+        StorageLive(_6);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
-        _3 = move _5;                    // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
+        _6 = &mut (*(*_4));              // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
+        _5 = &mut (*_6);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
+        _3 = &mut (*_5);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
+        StorageDead(_6);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
         StorageDead(_5);                 // scope 1 at $SRC_DIR/liballoc/boxed.rs:LL:COL
         _2 = &mut (*_3);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:15
         StorageDead(_4);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:14: 8:15

src/test/mir-opt/nrvo-simple/rustc.nrvo.RenameReturnPlace.diff

@@ -26,12 +26,17 @@
                                            // + span: $DIR/nrvo-simple.rs:3:20: 3:21
                                            // + literal: Const { ty: u8, val: Value(Scalar(0x00)) }
           StorageLive(_3);                 // scope 1 at $DIR/nrvo-simple.rs:4:5: 4:19
+          StorageLive(_5);                 // scope 1 at $DIR/nrvo-simple.rs:4:10: 4:18
+          StorageLive(_6);                 // scope 1 at $DIR/nrvo-simple.rs:4:10: 4:18
 -         _6 = &mut _2;                    // scope 1 at $DIR/nrvo-simple.rs:4:10: 4:18
 +         _6 = &mut _0;                    // scope 1 at $DIR/nrvo-simple.rs:4:10: 4:18
-          _3 = move _1(move _6) -> bb1;    // scope 1 at $DIR/nrvo-simple.rs:4:5: 4:19
+          _5 = &mut (*_6);                 // scope 1 at $DIR/nrvo-simple.rs:4:10: 4:18
+          _3 = move _1(move _5) -> bb1;    // scope 1 at $DIR/nrvo-simple.rs:4:5: 4:19
       }
   
       bb1: {
+          StorageDead(_5);                 // scope 1 at $DIR/nrvo-simple.rs:4:18: 4:19
+          StorageDead(_6);                 // scope 1 at $DIR/nrvo-simple.rs:4:19: 4:20
           StorageDead(_3);                 // scope 1 at $DIR/nrvo-simple.rs:4:19: 4:20
 -         _0 = _2;                         // scope 1 at $DIR/nrvo-simple.rs:5:5: 5:8
 -         StorageDead(_2);                 // scope 0 at $DIR/nrvo-simple.rs:6:1: 6:2

src/test/ui-fulldeps/compiler-calls.rs

@@ -3,6 +3,7 @@
 
 // ignore-cross-compile
 // ignore-stage1
+// ignore-remote
 
 #![feature(rustc_private)]
 

src/test/ui-fulldeps/mod_dir_path_canonicalized.rs

@@ -1,6 +1,7 @@
 // run-pass
 // Testing that a librustc_ast can parse modules with canonicalized base path
 // ignore-cross-compile
+// ignore-remote
 
 #![feature(rustc_private)]
 

src/test/ui/suggestions/suggest-move-types.stderr

@@ -124,7 +124,7 @@ error[E0747]: lifetime provided when a type was expected
 LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=(), U, 'b, V, 'c>> {
    |                                                        ^^
    |
-   = note: type arguments must be provided before lifetime arguments
+   = note: lifetime arguments must be provided before type arguments
 
 error[E0747]: lifetime provided when a type was expected
   --> $DIR/suggest-move-types.rs:82:56
@@ -132,7 +132,7 @@ error[E0747]: lifetime provided when a type was expected
 LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, 'b, C=(), V, 'c>> {
    |                                                        ^^
    |
-   = note: type arguments must be provided before lifetime arguments
+   = note: lifetime arguments must be provided before type arguments
 
 error: aborting due to 12 previous errors
 

src/test/ui/variance-iterators-in-libcore.rs

@@ -1,9 +1,10 @@
 // run-pass
 
-#![allow(warnings)]
+#![allow(dead_code)]
 
-use std::iter::Zip;
+use std::iter::{Fuse, Zip};
 
+fn fuse_covariant<'a, I>(iter: Fuse<&'static I>) -> Fuse<&'a I> { iter }
 fn zip_covariant<'a, A, B>(iter: Zip<&'static A, &'static B>) -> Zip<&'a A, &'a B> { iter }
 
 fn main() { }

src/tools/compiletest/src/header.rs

@@ -853,6 +853,7 @@ impl Config {
             name == util::get_pointer_width(&self.target) ||    // pointer width
             name == self.stage_id.split('-').next().unwrap() || // stage
             (self.target != self.host && name == "cross-compile") ||
+            (self.remote_test_client.is_some() && name == "remote") ||
             match self.compare_mode {
                 Some(CompareMode::Nll) => name == "compare-mode-nll",
                 Some(CompareMode::Polonius) => name == "compare-mode-polonius",

src/tools/remote-test-client/src/main.rs

@@ -224,7 +224,7 @@ fn run(support_lib_count: usize, exe: String, all_args: Vec<String>) {
     // by the client.
     for (k, v) in env::vars() {
         match &k[..] {
-            "PATH" | "LD_LIBRARY_PATH" | "PWD" => continue,
+            "PATH" | "LD_LIBRARY_PATH" | "PWD" | "RUST_TEST_TMPDIR" => continue,
             _ => {}
         }
         t!(client.write_all(k.as_bytes()));

src/tools/remote-test-server/src/main.rs

@@ -41,6 +41,7 @@ macro_rules! t {
 
 static TEST: AtomicUsize = AtomicUsize::new(0);
 
+#[derive(Copy, Clone)]
 struct Config {
     pub remote: bool,
     pub verbose: bool,
@@ -71,6 +72,12 @@ impl Config {
     }
 }
 
+fn print_verbose(s: &str, conf: Config) {
+    if conf.verbose {
+        println!("{}", s);
+    }
+}
+
 fn main() {
     println!("starting test server");
 
@@ -83,16 +90,19 @@ fn main() {
     };
 
     let listener = t!(TcpListener::bind(bind_addr));
-    let work: PathBuf = if cfg!(target_os = "android") {
+    let (work, tmp): (PathBuf, PathBuf) = if cfg!(target_os = "android") {
-        "/data/tmp/work".into()
+        ("/data/tmp/work".into(), "/data/tmp/work/tmp".into())
     } else {
-        let mut temp_dir = env::temp_dir();
+        let mut work_dir = env::temp_dir();
-        temp_dir.push("work");
+        work_dir.push("work");
-        temp_dir
+        let mut tmp_dir = work_dir.clone();
+        tmp_dir.push("tmp");
+        (work_dir, tmp_dir)
     };
-    println!("listening!");
+    println!("listening on {}!", bind_addr);
 
     t!(fs::create_dir_all(&work));
+    t!(fs::create_dir_all(&tmp));
 
     let lock = Arc::new(Mutex::new(()));
 
@@ -103,22 +113,25 @@ fn main() {
             continue;
         }
         if &buf[..] == b"ping" {
+            print_verbose("Received ping", config);
             t!(socket.write_all(b"pong"));
         } else if &buf[..] == b"push" {
-            handle_push(socket, &work);
+            handle_push(socket, &work, config);
         } else if &buf[..] == b"run " {
             let lock = lock.clone();
             let work = work.clone();
-            thread::spawn(move || handle_run(socket, &work, &lock));
+            let tmp = tmp.clone();
+            thread::spawn(move || handle_run(socket, &work, &tmp, &lock, config));
         } else {
             panic!("unknown command {:?}", buf);
         }
     }
 }
 
-fn handle_push(socket: TcpStream, work: &Path) {
+fn handle_push(socket: TcpStream, work: &Path, config: Config) {
     let mut reader = BufReader::new(socket);
-    recv(&work, &mut reader);
+    let dst = recv(&work, &mut reader);
+    print_verbose(&format!("push {:#?}", dst), config);
 
     let mut socket = reader.into_inner();
     t!(socket.write_all(b"ack "));
@@ -134,7 +147,7 @@ impl Drop for RemoveOnDrop<'_> {
     }
 }
 
-fn handle_run(socket: TcpStream, work: &Path, lock: &Mutex<()>) {
+fn handle_run(socket: TcpStream, work: &Path, tmp: &Path, lock: &Mutex<()>, config: Config) {
     let mut arg = Vec::new();
     let mut reader = BufReader::new(socket);
 
@@ -201,6 +214,7 @@ fn handle_run(socket: TcpStream, work: &Path, lock: &Mutex<()>) {
     // binary is and then we'll download it all to the exe path we calculated
     // earlier.
     let exe = recv(&path, &mut reader);
+    print_verbose(&format!("run {:#?}", exe), config);
 
     let mut cmd = Command::new(&exe);
     cmd.args(args);
@@ -226,6 +240,9 @@ fn handle_run(socket: TcpStream, work: &Path, lock: &Mutex<()>) {
         cmd.env("LD_LIBRARY_PATH", format!("{}:{}", work.display(), path.display()));
     }
 
+    // Some tests assume RUST_TEST_TMPDIR exists
+    cmd.env("RUST_TEST_TMPDIR", tmp.to_owned());
+
     // Spawn the child and ferry over stdout/stderr to the socket in a framed
     // fashion (poor man's style)
     let mut child =