Auto merge of #101617 - Dylan-DPC:rollup-iiy4ipc, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #101366 (Restore old behaviour on broken UNC paths)
 - #101492 (Suggest adding array lengths to references to arrays if possible)
 - #101529 (Fix the example code and doctest for Formatter::sign_plus)
 - #101573 (update `ParamKindOrd`)
 - #101612 (Fix code generation of `Rvalue::Repeat` with 128 bit values)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast/src/ast.rs

@@ -33,7 +33,6 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use std::cmp::Ordering;
 use std::convert::TryFrom;
 use std::fmt;
 use std::mem;
@@ -324,46 +323,17 @@ pub type GenericBounds = Vec<GenericBound>;
 /// Specifies the enforced ordering for generic parameters. In the future,
 /// if we wanted to relax this order, we could override `PartialEq` and
 /// `PartialOrd`, to allow the kinds to be unordered.
-#[derive(Hash, Clone, Copy)]
+#[derive(Hash, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum ParamKindOrd {
     Lifetime,
-    Type,
-    Const,
-    // `Infer` is not actually constructed directly from the AST, but is implicitly constructed
-    // during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
-    Infer,
-}
-
-impl Ord for ParamKindOrd {
-    fn cmp(&self, other: &Self) -> Ordering {
-        use ParamKindOrd::*;
-        let to_int = |v| match v {
-            Lifetime => 0,
-            Infer | Type | Const => 1,
-        };
-
-        to_int(*self).cmp(&to_int(*other))
-    }
-}
-impl PartialOrd for ParamKindOrd {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-impl PartialEq for ParamKindOrd {
-    fn eq(&self, other: &Self) -> bool {
-        self.cmp(other) == Ordering::Equal
-    }
+    TypeOrConst,
 }
-impl Eq for ParamKindOrd {}
 
 impl fmt::Display for ParamKindOrd {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             ParamKindOrd::Lifetime => "lifetime".fmt(f),
-            ParamKindOrd::Type => "type".fmt(f),
-            ParamKindOrd::Const { .. } => "const".fmt(f),
-            ParamKindOrd::Infer => "infer".fmt(f),
+            ParamKindOrd::TypeOrConst => "type and const".fmt(f),
         }
     }
 }

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -839,10 +839,10 @@ fn validate_generic_param_order(
         let (kind, bounds, span) = (&param.kind, &param.bounds, ident.span);
         let (ord_kind, ident) = match &param.kind {
             GenericParamKind::Lifetime => (ParamKindOrd::Lifetime, ident.to_string()),
-            GenericParamKind::Type { default: _ } => (ParamKindOrd::Type, ident.to_string()),
+            GenericParamKind::Type { default: _ } => (ParamKindOrd::TypeOrConst, ident.to_string()),
             GenericParamKind::Const { ref ty, kw_span: _, default: _ } => {
                 let ty = pprust::ty_to_string(ty);
-                (ParamKindOrd::Const, format!("const {}: {}", ident, ty))
+                (ParamKindOrd::TypeOrConst, format!("const {}: {}", ident, ty))
             }
         };
         param_idents.push((kind, ord_kind, bounds, idx, ident));

compiler/rustc_codegen_llvm/src/common.rs

@@ -215,7 +215,11 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     }
 
     fn const_to_opt_uint(&self, v: &'ll Value) -> Option<u64> {
-        try_as_const_integral(v).map(|v| unsafe { llvm::LLVMConstIntGetZExtValue(v) })
+        try_as_const_integral(v).and_then(|v| unsafe {
+            let mut i = 0u64;
+            let success = llvm::LLVMRustConstIntGetZExtValue(v, &mut i);
+            success.then_some(i)
+        })
     }
 
     fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1096,7 +1096,7 @@ extern "C" {
     pub fn LLVMConstInt(IntTy: &Type, N: c_ulonglong, SignExtend: Bool) -> &Value;
     pub fn LLVMConstIntOfArbitraryPrecision(IntTy: &Type, Wn: c_uint, Ws: *const u64) -> &Value;
     pub fn LLVMConstReal(RealTy: &Type, N: f64) -> &Value;
-    pub fn LLVMConstIntGetZExtValue(ConstantVal: &ConstantInt) -> c_ulonglong;
+    pub fn LLVMRustConstIntGetZExtValue(ConstantVal: &ConstantInt, Value: &mut u64) -> bool;
     pub fn LLVMRustConstInt128Get(
         ConstantVal: &ConstantInt,
         SExt: bool,

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -87,7 +87,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     let size = bx.const_usize(dest.layout.size.bytes());
 
                     // Use llvm.memset.p0i8.* to initialize all zero arrays
-                    if bx.cx().const_to_opt_uint(v) == Some(0) {
+                    if bx.cx().const_to_opt_u128(v, false) == Some(0) {
                         let fill = bx.cx().const_u8(0);
                         bx.memset(start, fill, size, dest.align, MemFlags::empty());
                         return bx;

compiler/rustc_hir/src/hir.rs

@@ -300,9 +300,9 @@ impl GenericArg<'_> {
     pub fn to_ord(&self) -> ast::ParamKindOrd {
         match self {
             GenericArg::Lifetime(_) => ast::ParamKindOrd::Lifetime,
-            GenericArg::Type(_) => ast::ParamKindOrd::Type,
-            GenericArg::Const(_) => ast::ParamKindOrd::Const,
-            GenericArg::Infer(_) => ast::ParamKindOrd::Infer,
+            GenericArg::Type(_) | GenericArg::Const(_) | GenericArg::Infer(_) => {
+                ast::ParamKindOrd::TypeOrConst
+            }
         }
     }
 

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1618,6 +1618,14 @@ extern "C" LLVMValueRef LLVMRustConstInBoundsGEP2(LLVMTypeRef Ty,
   return wrap(ConstantExpr::getInBoundsGetElementPtr(unwrap(Ty), Val, IdxList));
 }
 
+extern "C" bool LLVMRustConstIntGetZExtValue(LLVMValueRef CV, uint64_t *value) {
+    auto C = unwrap<llvm::ConstantInt>(CV);
+    if (C->getBitWidth() > 64)
+      return false;
+    *value = C->getZExtValue();
+    return true;
+}
+
 // Returns true if both high and low were successfully set. Fails in case constant wasn’t any of
 // the common sizes (1, 8, 16, 32, 64, 128 bits)
 extern "C" bool LLVMRustConstInt128Get(LLVMValueRef CV, bool sext, uint64_t *high, uint64_t *low)

compiler/rustc_middle/src/ty/generics.rs

@@ -27,8 +27,9 @@ impl GenericParamDefKind {
     pub fn to_ord(&self) -> ast::ParamKindOrd {
         match self {
             GenericParamDefKind::Lifetime => ast::ParamKindOrd::Lifetime,
-            GenericParamDefKind::Type { .. } => ast::ParamKindOrd::Type,
-            GenericParamDefKind::Const { .. } => ast::ParamKindOrd::Const,
+            GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
+                ast::ParamKindOrd::TypeOrConst
+            }
         }
     }
 

compiler/rustc_typeck/src/collect/type_of.rs

@@ -65,8 +65,8 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
             let ty = item_ctxt.ast_ty_to_ty(hir_ty);
 
             // Iterate through the generics of the projection to find the one that corresponds to
-            // the def_id that this query was called with. We filter to only const args here as a
-            // precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't
+            // the def_id that this query was called with. We filter to only type and const args here
+            // as a precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't
             // but it can't hurt to be safe ^^
             if let ty::Projection(projection) = ty.kind() {
                 let generics = tcx.generics_of(projection.item_def_id);

library/std/src/sys/windows/path.rs

@@ -198,14 +198,7 @@ fn parse_next_component(path: &OsStr, verbatim: bool) -> (&OsStr, &OsStr) {
 
     match path.bytes().iter().position(|&x| separator(x)) {
         Some(separator_start) => {
-            let mut separator_end = separator_start + 1;
-
-            // a series of multiple separator characters is treated as a single separator,
-            // except in verbatim paths
-            while !verbatim && separator_end < path.len() && separator(path.bytes()[separator_end])
-            {
-                separator_end += 1;
-            }
+            let separator_end = separator_start + 1;
 
             let component = &path.bytes()[..separator_start];
 

library/std/src/sys/windows/path/tests.rs

@@ -31,16 +31,6 @@ fn test_parse_next_component() {
         parse_next_component(OsStr::new(r"servershare"), false),
         (OsStr::new(r"servershare"), OsStr::new(""))
     );
-
-    assert_eq!(
-        parse_next_component(OsStr::new(r"server/\//\/\\\\/////\/share"), false),
-        (OsStr::new(r"server"), OsStr::new(r"share"))
-    );
-
-    assert_eq!(
-        parse_next_component(OsStr::new(r"server\\\\\\\\\\\\\\share"), true),
-        (OsStr::new(r"server"), OsStr::new(r"\\\\\\\\\\\\\share"))
-    );
 }
 
 #[test]
@@ -126,3 +116,22 @@ fn test_windows_prefix_components() {
     assert_eq!(drive.as_os_str(), OsStr::new("C:"));
     assert_eq!(components.as_path(), Path::new(""));
 }
+
+/// See #101358.
+///
+/// Note that the exact behaviour here may change in the future.
+/// In which case this test will need to adjusted.
+#[test]
+fn broken_unc_path() {
+    use crate::path::Component;
+
+    let mut components = Path::new(r"\\foo\\bar\\").components();
+    assert_eq!(components.next(), Some(Component::RootDir));
+    assert_eq!(components.next(), Some(Component::Normal("foo".as_ref())));
+    assert_eq!(components.next(), Some(Component::Normal("bar".as_ref())));
+
+    let mut components = Path::new("//foo//bar//").components();
+    assert_eq!(components.next(), Some(Component::RootDir));
+    assert_eq!(components.next(), Some(Component::Normal("foo".as_ref())));
+    assert_eq!(components.next(), Some(Component::Normal("bar".as_ref())));
+}

src/test/ui/codegen/issue-101585-128bit-repeat.rs

@@ -0,0 +1,14 @@
+// Regression test for issue 101585.
+// run-pass
+
+fn main() {
+    fn min_array_ok() -> [i128; 1] {
+        [i128::MIN]
+    }
+    assert_eq!(min_array_ok(), [-170141183460469231731687303715884105728i128]);
+
+    fn min_array_nok() -> [i128; 1] {
+        [i128::MIN; 1]
+    }
+    assert_eq!(min_array_nok(), [-170141183460469231731687303715884105728i128]);
+}

src/test/ui/const-generics/argument_order.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/argument_order.rs:6:32
    |
 LL | struct AlsoBad<const N: usize, 'a, T, 'b, const M: usize, U> {
@@ -11,7 +11,7 @@ LL |     let _: AlsoBad<7, 'static, u32, 'static, 17, u16>;
    |                       ^^^^^^^
    |
    = note: lifetime arguments must be provided before type arguments
-   = help: reorder the arguments: lifetimes, then consts: `<'a, 'b, N, T, M, U>`
+   = help: reorder the arguments: lifetimes, then type and consts: `<'a, 'b, N, T, M, U>`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/const-param-before-other-params.rs

@@ -1,5 +1,5 @@
 fn bar<const X: u8, 'a>(_: &'a ()) {
-    //~^ ERROR lifetime parameters must be declared prior to const parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
 }
 
 fn foo<const X: u8, T>(_: &T) {}

src/test/ui/const-generics/const-param-before-other-params.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/const-param-before-other-params.rs:1:21
    |
 LL | fn bar<const X: u8, 'a>(_: &'a ()) {

src/test/ui/const-generics/defaults/intermixed-lifetime.rs

@@ -1,9 +1,9 @@
 // Checks that lifetimes cannot be interspersed between consts and types.
 
 struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
-//~^ Error lifetime parameters must be declared prior to const parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 struct Bar<const N: usize, T = u32, 'a>(&'a (), T);
-//~^ Error lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}

src/test/ui/const-generics/defaults/intermixed-lifetime.stderr

@@ -1,10 +1,10 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/intermixed-lifetime.rs:3:28
    |
 LL | struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
    |           -----------------^^---------- help: reorder the parameters: lifetimes, then consts and types: `<'a, const N: usize, T = u32>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/intermixed-lifetime.rs:6:37
    |
 LL | struct Bar<const N: usize, T = u32, 'a>(&'a (), T);

src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs

@@ -1,4 +1,4 @@
 struct Foo<const M: usize = 10, 'a>(&'a u32);
-//~^ Error lifetime parameters must be declared prior to const parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}

src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/param-order-err-pretty-prints-default.rs:1:33
    |
 LL | struct Foo<const M: usize = 10, 'a>(&'a u32);

src/test/ui/generics/issue-59508-1.rs

@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<T, 'a, 'b: 'a>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }

src/test/ui/generics/issue-59508-1.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-59508-1.rs:10:25
    |
 LL |     pub fn do_things<T, 'a, 'b: 'a>() {

src/test/ui/generics/issue-59508.fixed

@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<'a, 'b: 'a, T>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }

src/test/ui/generics/issue-59508.rs

@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<T, 'a, 'b: 'a>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }

src/test/ui/generics/issue-59508.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-59508.rs:10:25
    |
 LL |     pub fn do_things<T, 'a, 'b: 'a>() {

src/test/ui/generics/issue-80512-param-reordering-with-defaults.rs

@@ -1,4 +1,4 @@
 #![crate_type = "lib"]
 
 struct S<T = (), 'a>(&'a T);
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters

src/test/ui/generics/issue-80512-param-reordering-with-defaults.stderr

@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-80512-param-reordering-with-defaults.rs:3:18
    |
 LL | struct S<T = (), 'a>(&'a T);

src/test/ui/generics/lifetime-before-type-params.rs

@@ -1,11 +1,11 @@
 #![allow(unused)]
 fn first<T, 'a, 'b>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn second<'a, T, 'b>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn third<T, U, 'a>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn fourth<'a, T, 'b, U, 'c, V>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}

src/test/ui/generics/lifetime-before-type-params.stderr

@@ -1,22 +1,22 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:2:13
    |
 LL | fn first<T, 'a, 'b>() {}
    |         ----^^--^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:4:18
    |
 LL | fn second<'a, T, 'b>() {}
    |          --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:6:16
    |
 LL | fn third<T, U, 'a>() {}
    |         -------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, T, U>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:8:18
    |
 LL | fn fourth<'a, T, 'b, U, 'c, V>() {}