jiebi/CodeConvo huggingface dataset:
Code change:
Gives:
cc ICE-ing instead of user error on misuse seems somewhat okay given that it's an internal attribute, IMO.
agreed. We don't protect against mis-use of rustc internal attributes beyond making sure that you can't trivially create buggy code. I don't think we should put any effort into making this nicer to use and instead create the const-generic based replacement.

Related discussion:
text: use rustc_middle::ty::query::Providers; use rustc_middle::ty::TyCtxt; <del> use rustc_ast::{Attribute, LitKind, NestedMetaItem}; </del> <ins> use rustc_ast::{Attribute, Lit, LitKind, NestedMetaItem}; </ins> use rustc_errors::{pluralize, struct_span_err}; use rustc_hir as hir; use rustc_hir::def_id::LocalDefId;
Code change:
Gives:
cc ICE-ing instead of user error on misuse seems somewhat okay given that it's an internal attribute, IMO.
agreed. We don't protect against mis-use of rustc internal attributes beyond making sure that you can't trivially create buggy code. I don't think we should put any effort into making this nicer to use and instead create the const-generic based replacement.

Related discussion:
text: self.check_export_name(hir_id, &attr, span, target) } else if self.tcx.sess.check_name(attr, sym::rustc_args_required_const) { self.check_rustc_args_required_const(&attr, span, target, item) <ins> } else if self.tcx.sess.check_name(attr, sym::rustc_layout_scalar_valid_range_start) { self.check_rustc_layout_scalar_valid_range(&attr, span, target) } else if self.tcx.sess.check_name(attr, sym::rustc_layout_scalar_valid_range_end) { self.check_rustc_layout_scalar_valid_range(&attr, span, target) </ins> } else if self.tcx.sess.check_name(attr, sym::allow_internal_unstable) { self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs) } else if self.tcx.sess.check_name(attr, sym::rustc_allow_const_fn_unstable) {
Code change:
Gives:
cc ICE-ing instead of user error on misuse seems somewhat okay given that it's an internal attribute, IMO.
agreed. We don't protect against mis-use of rustc internal attributes beyond making sure that you can't trivially create buggy code. I don't think we should put any effort into making this nicer to use and instead create the const-generic based replacement.

Related discussion:
text: } } <ins> fn check_rustc_layout_scalar_valid_range( &self, attr: &Attribute, span: &Span, target: Target, ) -> bool { if target != Target::Struct { self.tcx .sess .struct_span_err(attr.span, "attribute should be applied to a struct") .span_label(*span, "not a struct") .emit(); return false; } let list = match attr.meta_item_list() { None => return false, Some(it) => it, }; if matches!(&list[..], &[NestedMetaItem::Literal(Lit { kind: LitKind::Int(..), .. })]) { true } else { self.tcx .sess .struct_span_err(attr.span, "expected exactly one integer literal argument") .emit(); false } } </ins> /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument. fn check_rustc_legacy_const_generics( &self,
Code change:
Gives:
cc ICE-ing instead of user error on misuse seems somewhat okay given that it's an internal attribute, IMO.
agreed. We don't protect against mis-use of rustc internal attributes beyond making sure that you can't trivially create buggy code. I don't think we should put any effort into making this nicer to use and instead create the const-generic based replacement.

Related discussion:
text: <ins> #![feature(rustc_attrs)] #[rustc_layout_scalar_valid_range_start(u32::MAX)] //~ ERROR pub struct A(u32); #[rustc_layout_scalar_valid_range_end(1, 2)] //~ ERROR pub struct B(u8); #[rustc_layout_scalar_valid_range_end(a = "a")] //~ ERROR pub struct C(i32); #[rustc_layout_scalar_valid_range_end(1)] //~ ERROR enum E { X = 1, Y = 14, } fn main() { let _ = A(0); let _ = B(0); let _ = C(0); let _ = E::X; } </ins>
Code change:
Gives:
cc ICE-ing instead of user error on misuse seems somewhat okay given that it's an internal attribute, IMO.
agreed. We don't protect against mis-use of rustc internal attributes beyond making sure that you can't trivially create buggy code. I don't think we should put any effort into making this nicer to use and instead create the const-generic based replacement.

Related discussion:
text: <ins> error: expected exactly one integer literal argument --> $DIR/invalid_rustc_layout_scalar_valid_range.rs:3:1 | LL | #[rustc_layout_scalar_valid_range_start(u32::MAX)] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: expected exactly one integer literal argument --> $DIR/invalid_rustc_layout_scalar_valid_range.rs:6:1 | LL | #[rustc_layout_scalar_valid_range_end(1, 2)] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: expected exactly one integer literal argument --> $DIR/invalid_rustc_layout_scalar_valid_range.rs:9:1 | LL | #[rustc_layout_scalar_valid_range_end(a = "a")] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: attribute should be applied to a struct --> $DIR/invalid_rustc_layout_scalar_valid_range.rs:12:1 | LL |   #[rustc_layout_scalar_valid_range_end(1)] |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ LL | / enum E { LL | |     X = 1, LL | |     Y = 14, LL | | } | |_- not a struct error: aborting due to 4 previous errors </ins>
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: pub struct Zip<A, B> { a: A, b: B, <del> // index and len are only used by the specialized version of zip </del> <ins> // index, len and a_len are only used by the specialized version of zip </ins> index: usize, len: usize, <ins> a_len: usize, </ins> } impl<A: Iterator, B: Iterator> Zip<A, B> { pub(in crate::iter) fn new(a: A, b: B) -> Zip<A, B> {
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: b, index: 0, // unused len: 0,   // unused <ins> a_len: 0, // unused </ins> } }
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: B: TrustedRandomAccess + Iterator, { fn new(a: A, b: B) -> Self { <del> let len = cmp::min(a.size(), b.size()); Zip { a, b, index: 0, len } </del> <ins> let a_len = a.size(); let len = cmp::min(a_len, b.size()); Zip { a, b, index: 0, len, a_len } </ins> } #[inline]
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: unsafe { Some((self.a.__iterator_get_unchecked(i), self.b.__iterator_get_unchecked(i))) } <del> } else if A::MAY_HAVE_SIDE_EFFECT && self.index < self.a.size() { </del> <ins> } else if A::MAY_HAVE_SIDE_EFFECT && self.index < self.a_len { </ins> let i = self.index; self.index += 1; self.len += 1;
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: for _ in 0..sz_a - self.len { self.a.next_back(); } <ins> self.a_len = self.len; </ins> } let sz_b = self.b.size(); if B::MAY_HAVE_SIDE_EFFECT && sz_b > self.len {
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: } if self.index < self.len { self.len -= 1; <ins> self.a_len -= 1; </ins> let i = self.len; // SAFETY: `i` is smaller than the previous value of `self.len`, // which is also smaller than or equal to `self.a.len()` and `self.b.len()`
Code change:
Here is called for potential side effects until , ignoring however that it could have already been called in with those indexes. that demonstrates how this can be exploited to get two mutable references to the same data and cause an use-after-free bug.
Assigning as part of the .
The gift that keeps on giving Maybe it is time to get rid of as it exists today and replace it with a ? One that imposes the additional requirement on the caller that it must bring the iterator back into a safe state after it is done iterating. The upside would be eliminating a lot of code in and enabling the same optimization for and similar sources. While the downside would be that external iteration (i.e. loops and manual calls to ) would cease to benefit from optimizations and only internal iteration methods (including ) would continue to do so.
I don't know, I feel like that would just make more complex to upheld the invariants. IMO a good improvement over the current would be separating forward and backward iteration, this way it becomes easier to keep track of the state and I think would also make it possible to implement them for
I don't see how separating the forward and backward state would help with a drop implementation. The issue is that the source () currently does not have access to that state, instead the consumer drives the iteration by direct access through and never informs the source about it.
It would help because it allows the source iterator to keep track of its state by updating it when the method is called. Anyway, looks like someone already and it resulted in worse optimizations, but maybe LLVM got better in the meantime, or maybe that implementation could have been better. Anyway I don't think this is the right place to discuss this, a topic on zulip would probably be better.
https://rust-

Related discussion:
text: panic!(); } } <ins> #[test] fn test_issue_82291() { use std::cell::Cell; let mut v1 = [()]; let v2 = [()]; let called = Cell::new(0); let mut zip = v1 .iter_mut() .map(|r| { called.set(called.get() + 1); r }) .zip(&v2); zip.next_back(); assert_eq!(called.get(), 1); zip.next(); assert_eq!(called.get(), 1); } </ins>
Code change:
<!-- Thank you for filing a bug report! Please provide a short summary of the bug, along with any information you feel relevant to replicating the bug. --I tried this code: I expected to see this happen: I expected that the help text would give syntactically correct code, or that there would be no help text. Instead, this happened: The provided code snippet is not valid - it tries to deference the else-block, which is impossible. Better would be to put the inside the else-block. <!-- If you're using the stable version of the compiler, you should also check if the bug also exists in the beta or nightly versions. --: Also occurs on stable, 1.50.0. <!-- TRIAGEBOTSTART --<!-- TRIAGEBOTASSIGNSTART --<!-- TRIAGEBOTASSIGNDATASTARTTRIAGEBOTASSIGNDATAEND --<!-- TRIAGEBOTASSIGNEND --<!-- TRIAGEBOTEND --
claim I have a fix for this bug + an improvement. Gotta got for now but will submit the PR later today.

Related discussion:
text: expr } <ins> pub fn peel_blocks(&self) -> &Self { let mut expr = self; while let ExprKind::Block(Block { expr: Some(inner), .. }, _) = &expr.kind { expr = inner; } expr } </ins> pub fn can_have_side_effects(&self) -> bool { match self.peel_drop_temps().kind { ExprKind::Path(_) | ExprKind::Lit(_) => false,
Code change:
<!-- Thank you for filing a bug report! Please provide a short summary of the bug, along with any information you feel relevant to replicating the bug. --I tried this code: I expected to see this happen: I expected that the help text would give syntactically correct code, or that there would be no help text. Instead, this happened: The provided code snippet is not valid - it tries to deference the else-block, which is impossible. Better would be to put the inside the else-block. <!-- If you're using the stable version of the compiler, you should also check if the bug also exists in the beta or nightly versions. --: Also occurs on stable, 1.50.0. <!-- TRIAGEBOTSTART --<!-- TRIAGEBOTASSIGNSTART --<!-- TRIAGEBOTASSIGNDATASTARTTRIAGEBOTASSIGNDATAEND --<!-- TRIAGEBOTASSIGNEND --<!-- TRIAGEBOTEND --
claim I have a fix for this bug + an improvement. Gotta got for now but will submit the PR later today.

Related discussion:
text: } _ if sp == expr.span && !is_macro => { if let Some(steps) = self.deref_steps(checked_ty, expected) { <ins> let expr = expr.peel_blocks(); </ins> if steps == 1 { <del> // For a suggestion to make sense, the type would need to be `Copy`. if self.infcx.type_is_copy_modulo_regions(self.param_env, expected, sp) { if let Ok(code) = sm.span_to_snippet(sp) { </del> <ins> if let hir::ExprKind::AddrOf(_, mutbl, inner) = expr.kind { // If the expression has `&`, removing it would fix the error let prefix_span = expr.span.with_hi(inner.span.lo()); let message = match mutbl { hir::Mutability::Not => "consider removing the `&`", hir::Mutability::Mut => "consider removing the `&mut`", }; let suggestion = String::new(); return Some(( prefix_span, message, suggestion, Applicability::MachineApplicable, )); } else if self.infcx.type_is_copy_modulo_regions( self.param_env, expected, sp, ) { // For this suggestion to make sense, the type would need to be `Copy`. if let Ok(code) = sm.span_to_snippet(expr.span) { </ins> let message = if checked_ty.is_region_ptr() { "consider dereferencing the borrow" } else {
Code change:
<!-- Thank you for filing a bug report! Please provide a short summary of the bug, along with any information you feel relevant to replicating the bug. --I tried this code: I expected to see this happen: I expected that the help text would give syntactically correct code, or that there would be no help text. Instead, this happened: The provided code snippet is not valid - it tries to deference the else-block, which is impossible. Better would be to put the inside the else-block. <!-- If you're using the stable version of the compiler, you should also check if the bug also exists in the beta or nightly versions. --: Also occurs on stable, 1.50.0. <!-- TRIAGEBOTSTART --<!-- TRIAGEBOTASSIGNSTART --<!-- TRIAGEBOTASSIGNDATASTARTTRIAGEBOTASSIGNDATAEND --<!-- TRIAGEBOTASSIGNEND --<!-- TRIAGEBOTEND --
claim I have a fix for this bug + an improvement. Gotta got for now but will submit the PR later today.

Related discussion:
text: format!("*{}", code) }; return Some(( <del> sp, </del> <ins> expr.span, </ins> message, suggestion, Applicability::MachineApplicable,