Auto merge of #71431 - Dylan-DPC:rollup-rvm6tfy, r=Dylan-DPC

Rollup of 4 pull requests

Successful merges:

 - #71280 (Miri: mplace_access_checked: offer option to force different alignment on place)
 - #71336 (Exhaustively match on `{Statement,Terminator}Kind` during const checking)
 - #71370 (Added detailed error code explanation for issue E0696 in Rust compiler.)
 - #71401 (visit_place_base is just visit_local)

Failed merges:

r? @ghost

src/librustc_codegen_ssa/mir/analyze.rs

@@ -204,7 +204,7 @@ impl<Bx: BuilderMethods<'a, 'tcx>> LocalAnalyzer<'mir, 'a, 'tcx, Bx> {
  };
  }
 
- self.visit_place_base(&place_ref.local, context, location);
+ self.visit_local(&place_ref.local, context, location);
  self.visit_projection(place_ref.local, place_ref.projection, context, location);
  }
  }

src/librustc_error_codes/error_codes.rs

@@ -386,6 +386,7 @@ E0691: include_str!("./error_codes/E0691.md"),
 E0692: include_str!("./error_codes/E0692.md"),
 E0693: include_str!("./error_codes/E0693.md"),
 E0695: include_str!("./error_codes/E0695.md"),
+E0696: include_str!("./error_codes/E0696.md"),
 E0697: include_str!("./error_codes/E0697.md"),
 E0698: include_str!("./error_codes/E0698.md"),
 E0699: include_str!("./error_codes/E0699.md"),
@@ -604,7 +605,6 @@ E0753: include_str!("./error_codes/E0753.md"),
  E0687, // in-band lifetimes cannot be used in `fn`/`Fn` syntax
  E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
 // E0694, // an unknown tool name found in scoped attributes
- E0696, // `continue` pointing to a labeled block
 // E0702, // replaced with a generic attribute input check
 // E0707, // multiple elided lifetimes used in arguments of `async fn`
 // E0709, // multiple different lifetimes used in arguments of `async fn`

src/librustc_error_codes/error_codes/E0696.md

@@ -0,0 +1,49 @@
+A function is using `continue` keyword incorrectly.
+
+Erroneous code example:
+
+```compile_fail,E0696
+fn continue_simple() {
+ 'b: {
+ continue; // error!
+ }
+}
+fn continue_labeled() {
+ 'b: {
+ continue 'b; // error!
+ }
+}
+fn continue_crossing() {
+ loop {
+ 'b: {
+ continue; // error!
+ }
+ }
+}
+```
+
+Here we have used the `continue` keyword incorrectly. As we
+have seen above that `continue` pointing to a labeled block.
+
+To fix this we have to use the labeled block properly.
+For example:
+
+```
+fn continue_simple() {
+ 'b: loop {
+ continue ; // ok!
+ }
+}
+fn continue_labeled() {
+ 'b: loop {
+ continue 'b; // ok!
+ }
+}
+fn continue_crossing() {
+ loop {
+ 'b: loop {
+ continue; // ok!
+ }
+ }
+}
+```

src/librustc_middle/mir/visit.rs

@@ -163,13 +163,6 @@ macro_rules! make_mir_visitor {
  self.super_place(place, context, location);
  }
 
- fn visit_place_base(&mut self,
- local: & $($mutability)? Local,
- context: PlaceContext,
- location: Location) {
- self.super_place_base(local, context, location);
- }
-
  visit_place_fns!($($mutability)?);
 
  fn visit_constant(&mut self,
@@ -710,13 +703,6 @@ macro_rules! make_mir_visitor {
  );
  }
 
- fn super_place_base(&mut self,
- local: & $($mutability)? Local,
- context: PlaceContext,
- location: Location) {
- self.visit_local(local, context, location);
- }
-
  fn super_local_decl(&mut self,
  local: Local,
  local_decl: & $($mutability)? LocalDecl<'tcx>) {
@@ -847,7 +833,7 @@ macro_rules! visit_place_fns {
  context: PlaceContext,
  location: Location,
  ) {
- self.visit_place_base(&mut place.local, context, location);
+ self.visit_local(&mut place.local, context, location);
 
  if let Some(new_projection) = self.process_projection(&place.projection, location) {
  place.projection = self.tcx().intern_place_elems(&new_projection);
@@ -936,7 +922,7 @@ macro_rules! visit_place_fns {
  };
  }
 
- self.visit_place_base(&place.local, context, location);
+ self.visit_local(&place.local, context, location);
 
  self.visit_projection(place.local, &place.projection, context, location);
  }

src/librustc_mir/interpret/place.rs

@@ -333,7 +333,7 @@ where
  let val = self.read_immediate(src)?;
  trace!("deref to {} on {:?}", val.layout.ty, *val);
  let place = self.ref_to_mplace(val)?;
- self.mplace_access_checked(place)
+ self.mplace_access_checked(place, None)
  }
 
  /// Check if the given place is good for memory access with the given
@@ -358,15 +358,20 @@ where
 
  /// Return the "access-checked" version of this `MPlace`, where for non-ZST
  /// this is definitely a `Pointer`.
+ ///
+ /// `force_align` must only be used when correct alignment does not matter,
+ /// like in Stacked Borrows.
  pub fn mplace_access_checked(
  &self,
  mut place: MPlaceTy<'tcx, M::PointerTag>,
+ force_align: Option<Align>,
  ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
  let (size, align) = self
  .size_and_align_of_mplace(place)?
  .unwrap_or((place.layout.size, place.layout.align.abi));
  assert!(place.mplace.align <= align, "dynamic alignment less strict than static one?");
- place.mplace.align = align; // maximally strict checking
+ // Check (stricter) dynamic alignment, unless forced otherwise.
+ place.mplace.align = force_align.unwrap_or(align);
  // When dereferencing a pointer, it must be non-NULL, aligned, and live.
  if let Some(ptr) = self.check_mplace_access(place, Some(size))? {
  place.mplace.ptr = ptr.into();

src/librustc_mir/monomorphize/collector.rs

@@ -648,7 +648,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
  self.super_terminator_kind(kind, location);
  }
 
- fn visit_place_base(
+ fn visit_local(
  &mut self,
  _place_local: &Local,
  _context: mir::visit::PlaceContext,

src/librustc_mir/transform/check_consts/ops.rs

@@ -147,6 +147,10 @@ impl NonConstOp for IfOrMatch {
  }
 }
 
+#[derive(Debug)]
+pub struct InlineAsm;
+impl NonConstOp for InlineAsm {}
+
 #[derive(Debug)]
 pub struct LiveDrop;
 impl NonConstOp for LiveDrop {

src/librustc_mir/transform/check_consts/validation.rs

@@ -276,7 +276,7 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
  PlaceContext::MutatingUse(MutatingUseContext::Borrow)
  }
  };
- self.visit_place_base(&place.local, ctx, location);
+ self.visit_local(&place.local, ctx, location);
  self.visit_projection(place.local, reborrowed_proj, ctx, location);
  return;
  }
@@ -289,7 +289,7 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
  }
  Mutability::Mut => PlaceContext::MutatingUse(MutatingUseContext::AddressOf),
  };
- self.visit_place_base(&place.local, ctx, location);
+ self.visit_local(&place.local, ctx, location);
  self.visit_projection(place.local, reborrowed_proj, ctx, location);
  return;
  }
@@ -386,14 +386,13 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
  }
  }
 
- fn visit_place_base(&mut self, place_local: &Local, context: PlaceContext, location: Location) {
+ fn visit_local(&mut self, place_local: &Local, context: PlaceContext, location: Location) {
  trace!(
- "visit_place_base: place_local={:?} context={:?} location={:?}",
+ "visit_local: place_local={:?} context={:?} location={:?}",
  place_local,
  context,
  location,
  );
- self.super_place_base(place_local, context, location);
  }
 
  fn visit_operand(&mut self, op: &Operand<'tcx>, location: Location) {
@@ -478,14 +477,24 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
  StatementKind::Assign(..) | StatementKind::SetDiscriminant { .. } => {
  self.super_statement(statement, location);
  }
- StatementKind::FakeRead(FakeReadCause::ForMatchedPlace, _) => {
+
+ StatementKind::FakeRead(
+ FakeReadCause::ForMatchedPlace
+ | FakeReadCause::ForMatchGuard
+ | FakeReadCause::ForGuardBinding,
+ _,
+ ) => {
+ self.super_statement(statement, location);
  self.check_op(ops::IfOrMatch);
  }
- // FIXME(eddyb) should these really do nothing?
- StatementKind::FakeRead(..)
+ StatementKind::LlvmInlineAsm { .. } => {
+ self.super_statement(statement, location);
+ self.check_op(ops::InlineAsm);
+ }
+
+ StatementKind::FakeRead(FakeReadCause::ForLet | FakeReadCause::ForIndex, _)
  | StatementKind::StorageLive(_)
  | StatementKind::StorageDead(_)
- | StatementKind::LlvmInlineAsm { .. }
  | StatementKind::Retag { .. }
  | StatementKind::AscribeUserType(..)
  | StatementKind::Nop => {}
@@ -572,7 +581,19 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
  }
  }
 
- _ => {}
+ // FIXME: Some of these are only caught by `min_const_fn`, but should error here
+ // instead.
+ TerminatorKind::Abort
+ | TerminatorKind::Assert { .. }
+ | TerminatorKind::FalseEdges { .. }
+ | TerminatorKind::FalseUnwind { .. }
+ | TerminatorKind::GeneratorDrop
+ | TerminatorKind::Goto { .. }
+ | TerminatorKind::Resume
+ | TerminatorKind::Return
+ | TerminatorKind::SwitchInt { .. }
+ | TerminatorKind::Unreachable
+ | TerminatorKind::Yield { .. } => {}
  }
  }
 }

src/librustc_mir/transform/generator.rs

@@ -115,7 +115,7 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor<'tcx> {
  self.tcx,
  );
  } else {
- self.visit_place_base(&mut place.local, context, location);
+ self.visit_local(&mut place.local, context, location);
 
  for elem in place.projection.iter() {
  if let PlaceElem::Index(local) = elem {
@@ -154,7 +154,7 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
  self.tcx,
  );
  } else {
- self.visit_place_base(&mut place.local, context, location);
+ self.visit_local(&mut place.local, context, location);
 
  for elem in place.projection.iter() {
  if let PlaceElem::Index(local) = elem {

src/test/ui/consts/inline_asm.rs

@@ -0,0 +1,6 @@
+#![feature(llvm_asm)]
+
+const _: () = unsafe { llvm_asm!("nop") };
+//~^ ERROR contains unimplemented expression type
+
+fn main() {}

src/test/ui/consts/inline_asm.stderr

@@ -0,0 +1,11 @@
+error[E0019]: constant contains unimplemented expression type
+ --> $DIR/inline_asm.rs:3:24
+ |
+LL | const _: () = unsafe { llvm_asm!("nop") };
+ | ^^^^^^^^^^^^^^^^
+ |
+ = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0019`.

src/test/ui/consts/miri_unleashed/inline_asm.rs

@@ -11,4 +11,6 @@ static TEST_BAD: () = {
  //~^ ERROR could not evaluate static initializer
  //~| NOTE in this expansion of llvm_asm!
  //~| NOTE inline assembly is not supported
+ //~| WARN skipping const checks
+ //~| NOTE in this expansion of llvm_asm!
 };

src/test/ui/consts/miri_unleashed/inline_asm.stderr

@@ -1,3 +1,11 @@
+warning: skipping const checks
+ --> $DIR/inline_asm.rs:10:14
+ |
+LL | unsafe { llvm_asm!("xor %eax, %eax" ::: "eax"); }
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0080]: could not evaluate static initializer
  --> $DIR/inline_asm.rs:10:14
  |
@@ -6,6 +14,6 @@ LL | unsafe { llvm_asm!("xor %eax, %eax" ::: "eax"); }
  |
  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0080`.

src/test/ui/label/label_break_value_continue.stderr

@@ -21,4 +21,5 @@ LL | continue;
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0695`.
+Some errors have detailed explanations: E0695, E0696.
+For more information about an error, try `rustc --explain E0695`.