Auto merge of rust-lang#86226 - JohnTitor:rollup-5ubdolf, r=JohnTitor

Rollup of 7 pull requests

Successful merges:

 - rust-lang#85800 (Fix some diagnostic issues with const_generics_defaults feature gate)
 - rust-lang#85823 (Do not suggest ampmut if rhs is already mutable)
 - rust-lang#86153 (Print dummy spans as `no-location`)
 - rust-lang#86174 (Detect incorrect vtable alignment during const eval)
 - rust-lang#86189 (Make `relate_type_and_mut` public)
 - rust-lang#86205 (Run full const-generics test for issue-72293)
 - rust-lang#86217 (Remove "generic type" in boxed.rs)

Failed merges:

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

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -938,8 +938,11 @@ fn validate_generic_param_order(
                 }
                 GenericParamKind::Type { default: None } => (),
                 GenericParamKind::Lifetime => (),
-                // FIXME(const_generics_defaults)
-                GenericParamKind::Const { ty: _, kw_span: _, default: _ } => (),
+                GenericParamKind::Const { ty: _, kw_span: _, default: Some(default) } => {
+                    ordered_params += " = ";
+                    ordered_params += &pprust::expr_to_string(&*default.value);
+                }
+                GenericParamKind::Const { ty: _, kw_span: _, default: None } => (),
             }
             first = false;
         }
@@ -959,7 +962,7 @@ fn validate_generic_param_order(
             span,
             &format!(
                 "reorder the parameters: lifetimes, {}",
-                if sess.features_untracked().const_generics {
+                if sess.features_untracked().unordered_const_ty_params() {
                     "then consts and types"
                 } else {
                     "then types, then consts"

compiler/rustc_middle/src/ty/diagnostics.rs

@@ -54,7 +54,7 @@ impl<'tcx> TyS<'tcx> {
     /// ADTs with no type arguments.
     pub fn is_simple_text(&self) -> bool {
         match self.kind() {
-            Adt(_, substs) => substs.types().next().is_none(),
+            Adt(_, substs) => substs.non_erasable_generics().next().is_none(),
             Ref(_, ty, _) => ty.is_simple_text(),
             _ => self.is_simple_ty(),
         }

compiler/rustc_middle/src/ty/relate.rs

@@ -112,7 +112,7 @@ pub trait Relate<'tcx>: TypeFoldable<'tcx> + Copy {
 ///////////////////////////////////////////////////////////////////////////
 // Relate impls
 
-fn relate_type_and_mut<'tcx, R: TypeRelation<'tcx>>(
+pub fn relate_type_and_mut<'tcx, R: TypeRelation<'tcx>>(
     relation: &mut R,
     a: ty::TypeAndMut<'tcx>,
     b: ty::TypeAndMut<'tcx>,

compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs

@@ -902,9 +902,13 @@ fn suggest_ampmut<'tcx>(
             {
                 let lt_name = &src[1..ws_pos];
                 let ty = &src[ws_pos..];
-                return (assignment_rhs_span, format!("&{} mut {}", lt_name, ty));
+                if !ty.trim_start().starts_with("mut") {
+                    return (assignment_rhs_span, format!("&{} mut {}", lt_name, ty));
+                }
             } else if let Some(stripped) = src.strip_prefix('&') {
-                return (assignment_rhs_span, format!("&mut {}", stripped));
+                if !stripped.trim_start().starts_with("mut") {
+                    return (assignment_rhs_span, format!("&mut {}", stripped));
+                }
             }
         }
     }

compiler/rustc_mir/src/interpret/traits.rs

@@ -158,13 +158,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let size = u64::try_from(self.force_bits(size, pointer_size)?).unwrap();
         let align = vtable.read_ptr_sized(pointer_size * 2)?.check_init()?;
         let align = u64::try_from(self.force_bits(align, pointer_size)?).unwrap();
+        let align = Align::from_bytes(align)
+            .map_err(|e| err_ub_format!("invalid vtable: alignment {}", e))?;
 
         if size >= self.tcx.data_layout.obj_size_bound() {
             throw_ub_format!(
                 "invalid vtable: \
                 size is bigger than largest supported object"
             );
         }
-        Ok((Size::from_bytes(size), Align::from_bytes(align).unwrap()))
+        Ok((Size::from_bytes(size), align))
     }
 }

compiler/rustc_span/src/source_map.rs

@@ -407,7 +407,7 @@ impl SourceMap {
     }
 
     fn span_to_string(&self, sp: Span, prefer_local: bool) -> String {
-        if self.files.borrow().source_files.is_empty() && sp.is_dummy() {
+        if self.files.borrow().source_files.is_empty() || sp.is_dummy() {
             return "no-location".to_string();
         }
 

library/alloc/src/boxed.rs

@@ -1209,7 +1209,7 @@ impl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A> {
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "from_for_ptrs", since = "1.6.0")]
 impl<T> From<T> for Box<T> {
-    /// Converts a generic type `T` into a `Box<T>`
+    /// Converts a `T` into a `Box<T>`
     ///
     /// The conversion allocates on the heap and moves `t`
     /// from the stack into it.

src/test/mir-opt/generator_storage_dead_unwind.main-{closure#0}.StateTransform.before.mir

@@ -85,13 +85,13 @@ yields ()
     bb8 (cleanup): {
         StorageDead(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:15: 27:16
         StorageDead(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:16: 27:17
-        goto -> bb10;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:1:1: 1:1
+        goto -> bb10;                    // scope 2 at no-location
     }
 
     bb9 (cleanup): {
         StorageDead(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:15: 26:16
         StorageDead(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:16: 26:17
-        goto -> bb10;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:1:1: 1:1
+        goto -> bb10;                    // scope 2 at no-location
     }
 
     bb10 (cleanup): {

src/test/mir-opt/loop_test.main.SimplifyCfg-promote-consts.after.mir

@@ -43,7 +43,7 @@ fn main() -> () {
         _6 = const 1_i32;                // scope 0 at $DIR/loop_test.rs:14:17: 14:18
         FakeRead(ForLet(None), _6);      // scope 0 at $DIR/loop_test.rs:14:13: 14:14
         StorageDead(_6);                 // scope 0 at $DIR/loop_test.rs:16:5: 16:6
-        goto -> bb3;                     // scope 0 at $DIR/loop_test.rs:1:1: 1:1
+        goto -> bb3;                     // scope 0 at no-location
     }
 
     bb5 (cleanup): {

src/test/mir-opt/match_arm_scopes.complicated_match.SimplifyCfg-initial.after-ElaborateDrops.after.diff

@@ -94,8 +94,8 @@
           _0 = const 3_i32;                // scope 0 at $DIR/match-arm-scopes.rs:15:59: 15:60
           StorageDead(_10);                // scope 0 at $DIR/match-arm-scopes.rs:15:72: 15:73
           StorageDead(_9);                 // scope 0 at $DIR/match-arm-scopes.rs:15:77: 15:78
--         goto -> bb23;                    // scope 0 at $DIR/match-arm-scopes.rs:1:1: 1:1
-+         goto -> bb20;                    // scope 0 at $DIR/match-arm-scopes.rs:1:1: 1:1
+-         goto -> bb23;                    // scope 0 at no-location
++         goto -> bb20;                    // scope 0 at no-location
       }
 
 -     bb10: {
@@ -150,8 +150,8 @@
           _0 = const 3_i32;                // scope 0 at $DIR/match-arm-scopes.rs:15:59: 15:60
           StorageDead(_13);                // scope 0 at $DIR/match-arm-scopes.rs:15:72: 15:73
           StorageDead(_12);                // scope 0 at $DIR/match-arm-scopes.rs:15:77: 15:78
--         goto -> bb23;                    // scope 0 at $DIR/match-arm-scopes.rs:1:1: 1:1
-+         goto -> bb20;                    // scope 0 at $DIR/match-arm-scopes.rs:1:1: 1:1
+-         goto -> bb23;                    // scope 0 at no-location
++         goto -> bb20;                    // scope 0 at no-location
       }
 
 -     bb15: {

src/test/mir-opt/while_storage.while_loop.PreCodegen.after.mir

@@ -40,7 +40,7 @@ fn while_loop(_1: bool) -> () {
 
     bb4: {
         StorageDead(_4);                 // scope 0 at $DIR/while-storage.rs:13:9: 13:10
-        goto -> bb6;                     // scope 0 at $DIR/while-storage.rs:1:1: 1:1
+        goto -> bb6;                     // scope 0 at no-location
     }
 
     bb5: {

src/test/ui/borrowck/issue-85765.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let mut test = Vec::new();
+    let rofl: &Vec<Vec<i32>> = &mut test;
+    //~^ HELP consider changing this to be a mutable reference
+    rofl.push(Vec::new());
+    //~^ ERROR cannot borrow `*rofl` as mutable, as it is behind a `&` reference
+    //~| NOTE `rofl` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+}

src/test/ui/borrowck/issue-85765.stderr

@@ -0,0 +1,12 @@
+error[E0596]: cannot borrow `*rofl` as mutable, as it is behind a `&` reference
+  --> $DIR/issue-85765.rs:5:5
+   |
+LL |     let rofl: &Vec<Vec<i32>> = &mut test;
+   |         ---- help: consider changing this to be a mutable reference: `&mut Vec<Vec<i32>>`
+LL |
+LL |     rofl.push(Vec::new());
+   |     ^^^^ `rofl` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0596`.

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

@@ -2,13 +2,13 @@ error: lifetime parameters must be declared prior to const parameters
   --> $DIR/intermixed-lifetime.rs:7:28
    |
 LL | struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
-   |           -----------------^^---------- help: reorder the parameters: lifetimes, then types, then consts: `<'a, const N: usize, T = u32>`
+   |           -----------------^^---------- 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
   --> $DIR/intermixed-lifetime.rs:10:37
    |
 LL | struct Bar<const N: usize, T = u32, 'a>(&'a (), T);
-   |           --------------------------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, const N: usize, T = u32>`
+   |           --------------------------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, const N: usize, T = u32>`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/defaults/mismatch.full.stderr

@@ -5,9 +5,12 @@ LL |     let e: Example::<13> = ();
    |            -------------   ^^ expected struct `Example`, found `()`
    |            |
    |            expected due to this
+   |
+   = note: expected struct `Example`
+           found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:14:34
+  --> $DIR/mismatch.rs:15:34
    |
 LL |     let e: Example2::<u32, 13> = ();
    |            -------------------   ^^ expected struct `Example2`, found `()`
@@ -18,7 +21,7 @@ LL |     let e: Example2::<u32, 13> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:16:34
+  --> $DIR/mismatch.rs:18:34
    |
 LL |     let e: Example3::<13, u32> = ();
    |            -------------------   ^^ expected struct `Example3`, found `()`
@@ -29,7 +32,7 @@ LL |     let e: Example3::<13, u32> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:18:28
+  --> $DIR/mismatch.rs:21:28
    |
 LL |     let e: Example3::<7> = ();
    |            -------------   ^^ expected struct `Example3`, found `()`
@@ -40,12 +43,15 @@ LL |     let e: Example3::<7> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:22:28
+  --> $DIR/mismatch.rs:24:28
    |
 LL |     let e: Example4::<7> = ();
    |            -------------   ^^ expected struct `Example4`, found `()`
    |            |
    |            expected due to this
+   |
+   = note: expected struct `Example4<7_usize>`
+           found unit type `()`
 
 error: aborting due to 5 previous errors
 

src/test/ui/const-generics/defaults/mismatch.min.stderr

@@ -5,9 +5,12 @@ LL |     let e: Example::<13> = ();
    |            -------------   ^^ expected struct `Example`, found `()`
    |            |
    |            expected due to this
+   |
+   = note: expected struct `Example`
+           found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:14:34
+  --> $DIR/mismatch.rs:15:34
    |
 LL |     let e: Example2::<u32, 13> = ();
    |            -------------------   ^^ expected struct `Example2`, found `()`
@@ -18,7 +21,7 @@ LL |     let e: Example2::<u32, 13> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:16:34
+  --> $DIR/mismatch.rs:18:34
    |
 LL |     let e: Example3::<13, u32> = ();
    |            -------------------   ^^ expected struct `Example3`, found `()`
@@ -29,7 +32,7 @@ LL |     let e: Example3::<13, u32> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:18:28
+  --> $DIR/mismatch.rs:21:28
    |
 LL |     let e: Example3::<7> = ();
    |            -------------   ^^ expected struct `Example3`, found `()`
@@ -40,12 +43,15 @@ LL |     let e: Example3::<7> = ();
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> $DIR/mismatch.rs:22:28
+  --> $DIR/mismatch.rs:24:28
    |
 LL |     let e: Example4::<7> = ();
    |            -------------   ^^ expected struct `Example4`, found `()`
    |            |
    |            expected due to this
+   |
+   = note: expected struct `Example4<7_usize>`
+           found unit type `()`
 
 error: aborting due to 5 previous errors
 

src/test/ui/const-generics/defaults/mismatch.rs

@@ -11,14 +11,17 @@ pub struct Example4<const N: usize=13, const M: usize=4>;
 fn main() {
     let e: Example::<13> = ();
     //~^ Error: mismatched types
+    //~| expected struct `Example`
     let e: Example2::<u32, 13> = ();
     //~^ Error: mismatched types
+    //~| expected struct `Example2`
     let e: Example3::<13, u32> = ();
     //~^ Error: mismatched types
+    //~| expected struct `Example3`
     let e: Example3::<7> = ();
     //~^ Error: mismatched types
-    // FIXME(const_generics_defaults): There should be a note for the error below, but it is
-    // missing.
+    //~| expected struct `Example3<7_usize>`
     let e: Example4::<7> = ();
     //~^ Error: mismatched types
+    //~| expected struct `Example4<7_usize>`
 }

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

@@ -0,0 +1,5 @@
+#![feature(const_generics_defaults)]
+struct Foo<const M: usize = 10, 'a>(&'a u32);
+//~^ Error lifetime parameters must be declared prior to const parameters
+
+fn main() {}

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

@@ -0,0 +1,8 @@
+error: lifetime parameters must be declared prior to const parameters
+  --> $DIR/param-order-err-pretty-prints-default.rs:2:33
+   |
+LL | struct Foo<const M: usize = 10, 'a>(&'a u32);
+   |           ----------------------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, const M: usize = 10>`
+
+error: aborting due to previous error
+

src/test/ui/const-generics/min_const_generics/transmute-const-param-static-reference.stderr → src/test/ui/const-generics/transmute-const-param-static-reference.min.stderr

@@ -1,5 +1,5 @@
 error: `&'static ()` is forbidden as the type of a const generic parameter
-  --> $DIR/transmute-const-param-static-reference.rs:1:23
+  --> $DIR/transmute-const-param-static-reference.rs:7:23
    |
 LL | struct Const<const P: &'static ()>;
    |                       ^^^^^^^^^^^

src/test/ui/const-generics/transmute-const-param-static-reference.rs

@@ -0,0 +1,16 @@
+// revisions: full min
+//[full] check-pass
+
+#![cfg_attr(full, feature(const_generics))]
+#![cfg_attr(full, allow(incomplete_features))]
+
+struct Const<const P: &'static ()>;
+//[min]~^ ERROR `&'static ()` is forbidden as the type of a const generic parameter
+
+fn main() {
+    const A: &'static () = unsafe {
+        std::mem::transmute(10 as *const ())
+    };
+
+    let _ = Const::<{A}>;
+}

src/test/ui/consts/const-eval/ub-incorrect-vtable.rs

@@ -0,0 +1,21 @@
+// This test contains code with incorrect vtables in a const context:
+// - from issue 86132: a trait object with invalid alignment caused an ICE in const eval, and now
+//   triggers an error
+// - a similar test that triggers a previously-untested const UB error: emitted close to the above
+//   error, it checks the correctness of the size
+
+trait Trait {}
+
+const INVALID_VTABLE_ALIGNMENT: &dyn Trait =
+    unsafe { std::mem::transmute((&92u8, &[0usize, 1usize, 1000usize])) };
+//~^ ERROR any use of this value will cause an error
+//~| WARNING this was previously accepted by the compiler
+//~| invalid vtable: alignment `1000` is not a power of 2
+
+const INVALID_VTABLE_SIZE: &dyn Trait =
+    unsafe { std::mem::transmute((&92u8, &[1usize, usize::MAX, 1usize])) };
+//~^ ERROR any use of this value will cause an error
+//~| WARNING this was previously accepted by the compiler
+//~| invalid vtable: size is bigger than largest supported object
+
+fn main() {}