Rollup of 6 pull requests

src/librustc_error_codes/error_codes/E0746.md

@@ -1,4 +1,4 @@
-Return types cannot be `dyn Trait`s as they must be `Sized`.
+An unboxed trait object was used as a return value.
 
 Erroneous code example:
 
@@ -13,11 +13,13 @@ impl T for S {
 
 // Having the trait `T` as return type is invalid because
 // unboxed trait objects do not have a statically known size:
-fn foo() -> dyn T {
+fn foo() -> dyn T { // error!
     S(42)
 }
 ```
 
+Return types cannot be `dyn Trait`s as they must be `Sized`.
+
 To avoid the error there are a couple of options.
 
 If there is a single type involved, you can use [`impl Trait`]:
@@ -32,7 +34,7 @@ If there is a single type involved, you can use [`impl Trait`]:
 # }
 // The compiler will select `S(usize)` as the materialized return type of this
 // function, but callers will only know that the return type implements `T`.
-fn foo() -> impl T {
+fn foo() -> impl T { // ok!
     S(42)
 }
 ```
@@ -57,7 +59,7 @@ impl T for O {
 
 // This now returns a "trait object" and callers are only be able to access
 // associated items from `T`.
-fn foo(x: bool) -> Box<dyn T> {
+fn foo(x: bool) -> Box<dyn T> { // ok!
     if x {
         Box::new(S(42))
     } else {

src/librustc_feature/active.rs

@@ -576,7 +576,7 @@ declare_features! (
     /// Lazily evaluate constants. This allows constants to depend on type parameters.
     (active, lazy_normalization_consts, "1.46.0", Some(72219), None),
 
-    /// Alloc calling `transmute` in const fn
+    /// Allows calling `transmute` in const fn
     (active, const_fn_transmute, "1.46.0", Some(53605), None),
 
     // -------------------------------------------------------------------------

src/librustc_resolve/diagnostics.rs

@@ -1075,10 +1075,9 @@ impl<'a> Resolver<'a> {
         ) = binding.kind
         {
             let def_id = (&*self).parent(ctor_def_id).expect("no parent for a constructor");
-            if let Some(fields) = self.field_names.get(&def_id) {
-                let first_field = fields.first().expect("empty field list in the map");
-                return Some(fields.iter().fold(first_field.span, |acc, field| acc.to(field.span)));
-            }
+            let fields = self.field_names.get(&def_id)?;
+            let first_field = fields.first()?; // Handle `struct Foo()`
+            return Some(fields.iter().fold(first_field.span, |acc, field| acc.to(field.span)));
         }
         None
     }

src/test/mir-opt/const-promotion-extern-static.rs

@@ -1,7 +1,7 @@
+// ignore-endian-big
 extern "C" {
     static X: i32;
 }
-
 static Y: i32 = 42;
 
 // EMIT_MIR const_promotion_extern_static.BAR.PromoteTemps.diff

src/test/mir-opt/const_allocation.rs

@@ -1,5 +1,5 @@
+// ignore-endian-big
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
-
 static FOO: &[(Option<i32>, &[&str])] =
     &[(None, &[]), (None, &["foo", "bar"]), (Some(42), &["meh", "mop", "möp"])];
 

src/test/mir-opt/const_allocation2.rs

@@ -1,5 +1,5 @@
+// ignore-endian-big
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
-
 // EMIT_MIR const_allocation2.main.ConstProp.after.mir
 fn main() {
     FOO;

src/test/mir-opt/const_allocation3.rs

@@ -1,5 +1,5 @@
+// ignore-endian-big
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
-
 // EMIT_MIR const_allocation3.main.ConstProp.after.mir
 fn main() {
     FOO;

src/test/mir-opt/inline/inline-into-box-place.rs

@@ -1,8 +1,8 @@
+// ignore-endian-big
 // ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -Z mir-opt-level=3
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
 #![feature(box_syntax)]
-
 // EMIT_MIR inline_into_box_place.main.Inline.diff
 fn main() {
     let _x: Box<Vec<u32>> = box Vec::new();

src/test/ui/higher-rank-trait-bounds/issue-59311.rs

@@ -0,0 +1,20 @@
+// Regression test for #59311. The test is taken from
+// rust-lang/rust/issues/71546#issuecomment-620638437
+// as they seem to have the same cause.
+
+// FIXME: It's not clear that this code ought to report
+// an error, but the regression test is here to ensure
+// that it does not ICE. See discussion on #74889 for details.
+
+pub trait T {
+    fn t<F: Fn()>(&self, _: F) {}
+}
+
+pub fn crash<V>(v: &V)
+where
+    for<'a> &'a V: T + 'static,
+{
+    v.t(|| {}); //~ ERROR: higher-ranked subtype error
+}
+
+fn main() {}

src/test/ui/higher-rank-trait-bounds/issue-59311.stderr

@@ -0,0 +1,8 @@
+error: higher-ranked subtype error
+  --> $DIR/issue-59311.rs:17:9
+   |
+LL |     v.t(|| {});
+   |         ^^^^^
+
+error: aborting due to previous error
+

src/test/ui/privacy/issue-75062-fieldless-tuple-struct.rs

@@ -0,0 +1,10 @@
+// Regression test for issue #75062
+// Tests that we don't ICE on a privacy error for a fieldless tuple struct.
+
+mod foo {
+    struct Bar();
+}
+
+fn main() {
+    foo::Bar(); //~ ERROR tuple struct
+}

src/test/ui/privacy/issue-75062-fieldless-tuple-struct.stderr

@@ -0,0 +1,15 @@
+error[E0603]: tuple struct `Bar` is private
+  --> $DIR/issue-75062-fieldless-tuple-struct.rs:9:10
+   |
+LL |     foo::Bar();
+   |          ^^^ private tuple struct
+   |
+note: the tuple struct `Bar` is defined here
+  --> $DIR/issue-75062-fieldless-tuple-struct.rs:5:5
+   |
+LL |     struct Bar();
+   |     ^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0603`.

src/test/ui/simd/simd-intrinsic-generic-bitmask.rs

@@ -2,6 +2,7 @@
 #![allow(non_camel_case_types)]
 
 // ignore-emscripten
+// ignore-endian-big behavior of simd_bitmask is endian-specific
 
 // Test that the simd_bitmask intrinsic produces correct results.
 

src/test/ui/simd/simd-intrinsic-generic-select.rs

@@ -2,10 +2,7 @@
 #![allow(non_camel_case_types)]
 
 // ignore-emscripten
-// ignore-mips       behavior of simd_select_bitmask is endian-specific
-// ignore-mips64     behavior of simd_select_bitmask is endian-specific
-// ignore-powerpc    behavior of simd_select_bitmask is endian-specific
-// ignore-powerpc64  behavior of simd_select_bitmask is endian-specific
+// ignore-endian-big behavior of simd_select_bitmask is endian-specific
 
 // Test that the simd_select intrinsics produces correct results.
 

src/tools/compiletest/src/header.rs

@@ -827,6 +827,7 @@ 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") ||
+            (name == "endian-big" && util::is_big_endian(&self.target)) ||
             (self.remote_test_client.is_some() && name == "remote") ||
             match self.compare_mode {
                 Some(CompareMode::Nll) => name == "compare-mode-nll",

src/tools/compiletest/src/util.rs

@@ -99,6 +99,20 @@ pub const MSAN_SUPPORTED_TARGETS: &'static [&'static str] =
 pub const TSAN_SUPPORTED_TARGETS: &'static [&'static str] =
     &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
+const BIG_ENDIAN: &'static [&'static str] = &[
+    "armebv7r",
+    "mips",
+    "mips64",
+    "mipsisa32r6",
+    "mipsisa64r6",
+    "powerpc",
+    "powerpc64",
+    "s390x",
+    "sparc",
+    "sparc64",
+    "sparcv9",
+];
+
 pub fn matches_os(triple: &str, name: &str) -> bool {
     // For the wasm32 bare target we ignore anything also ignored on emscripten
     // and then we also recognize `wasm32-bare` as the os for the target
@@ -125,6 +139,12 @@ pub fn get_arch(triple: &str) -> &'static str {
     panic!("Cannot determine Architecture from triple");
 }
 
+/// Determine the endianness from `triple`
+pub fn is_big_endian(triple: &str) -> bool {
+    let triple_arch = triple.split('-').next().unwrap();
+    BIG_ENDIAN.contains(&triple_arch)
+}
+
 pub fn matches_env(triple: &str, name: &str) -> bool {
     if let Some(env) = triple.split('-').nth(3) { env.starts_with(name) } else { false }
 }

src/tools/publish_toolstate.py

@@ -42,7 +42,7 @@
 LABELS = {
     'miri': ['A-miri', 'C-bug'],
     'rls': ['A-rls', 'C-bug'],
-    'rustfmt': ['C-bug'],
+    'rustfmt': ['A-rustfmt', 'C-bug'],
     'book': ['C-bug'],
     'nomicon': ['C-bug'],
     'reference': ['C-bug'],