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Add help for trying to do C-like pointer arithmetics

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This commit is contained in:
许杰友 Jieyou Xu (Joe) 2023-06-04 10:18:09 +08:00
parent 8b35c0bb0f
commit 63d643da84
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GPG Key ID: C5FD5D32014FDB47
5 changed files with 135 additions and 0 deletions
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15
compiler/rustc_hir_typeck/src/expr.rs
View File

@ -2870,6 +2870,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
}
}
if base_t.is_unsafe_ptr() && idx_t.is_integral() {
err.multipart_suggestion(
"consider using `wrapping_add` or `add` for indexing into raw pointer",
vec![
(base.span.between(idx.span), ".wrapping_add(".to_owned()),
(
idx.span.shrink_to_hi().until(expr.span.shrink_to_hi()),
")".to_owned(),
),
],
Applicability::MaybeIncorrect,
);
}
let reported = err.emit();
self.tcx.ty_error(reported)
}

46
compiler/rustc_hir_typeck/src/op.rs
View File

@ -521,6 +521,52 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
}
// Suggest using `add`, `offset` or `offset_from` for pointer - {integer},
// pointer + {integer} or pointer - pointer.
if op.span.can_be_used_for_suggestions() {
match op.node {
hir::BinOpKind::Add if lhs_ty.is_unsafe_ptr() && rhs_ty.is_integral() => {
err.multipart_suggestion(
"consider using `wrapping_add` or `add` for pointer + {integer}",
vec![
(
lhs_expr.span.between(rhs_expr.span),
".wrapping_add(".to_owned(),
),
(rhs_expr.span.shrink_to_hi(), ")".to_owned()),
],
Applicability::MaybeIncorrect,
);
}
hir::BinOpKind::Sub => {
if lhs_ty.is_unsafe_ptr() && rhs_ty.is_integral() {
err.multipart_suggestion(
"consider using `wrapping_sub` or `sub` for pointer - {integer}",
vec![
(lhs_expr.span.between(rhs_expr.span), ".wrapping_sub(".to_owned()),
(rhs_expr.span.shrink_to_hi(), ")".to_owned()),
],
Applicability::MaybeIncorrect
);
}
if lhs_ty.is_unsafe_ptr() && rhs_ty.is_unsafe_ptr() {
err.multipart_suggestion(
"consider using `offset_from` for pointer - pointer if the pointers point to the same allocation",
vec![
(lhs_expr.span.shrink_to_lo(), "unsafe { ".to_owned()),
(lhs_expr.span.between(rhs_expr.span), ".offset_from(".to_owned()),
(rhs_expr.span.shrink_to_hi(), ") }".to_owned()),
],
Applicability::MaybeIncorrect
);
}
}
_ => {}
}
}
let reported = err.emit();
self.tcx.ty_error(reported)
}

10
tests/ui/typeck/issue-112252-ptr-arithmetics-help.fixed Normal file
View File

@ -0,0 +1,10 @@
// run-rustfix
fn main() {
let _ptr1: *const u32 = std::ptr::null();
let _ptr2: *const u32 = std::ptr::null();
let _a = _ptr1.wrapping_add(5); //~ ERROR cannot add
let _b = _ptr1.wrapping_sub(5); //~ ERROR cannot subtract
let _c = unsafe { _ptr2.offset_from(_ptr1) }; //~ ERROR cannot subtract
let _d = _ptr1.wrapping_add(5); //~ ERROR cannot index
}

10
tests/ui/typeck/issue-112252-ptr-arithmetics-help.rs Normal file
View File

@ -0,0 +1,10 @@
// run-rustfix
fn main() {
let _ptr1: *const u32 = std::ptr::null();
let _ptr2: *const u32 = std::ptr::null();
let _a = _ptr1 + 5; //~ ERROR cannot add
let _b = _ptr1 - 5; //~ ERROR cannot subtract
let _c = _ptr2 - _ptr1; //~ ERROR cannot subtract
let _d = _ptr1[5]; //~ ERROR cannot index
}

54
tests/ui/typeck/issue-112252-ptr-arithmetics-help.stderr Normal file
View File

@ -0,0 +1,54 @@
error[E0369]: cannot add `{integer}` to `*const u32`
--> $DIR/issue-112252-ptr-arithmetics-help.rs:6:20
|
LL | let _a = _ptr1 + 5;
| ----- ^ - {integer}
| |
| *const u32
|
help: consider using `wrapping_add` or `add` for pointer + {integer}
|
LL | let _a = _ptr1.wrapping_add(5);
| ~~~~~~~~~~~~~~ +
error[E0369]: cannot subtract `{integer}` from `*const u32`
--> $DIR/issue-112252-ptr-arithmetics-help.rs:7:20
|
LL | let _b = _ptr1 - 5;
| ----- ^ - {integer}
| |
| *const u32
|
help: consider using `wrapping_sub` or `sub` for pointer - {integer}
|
LL | let _b = _ptr1.wrapping_sub(5);
| ~~~~~~~~~~~~~~ +
error[E0369]: cannot subtract `*const u32` from `*const u32`
--> $DIR/issue-112252-ptr-arithmetics-help.rs:8:20
|
LL | let _c = _ptr2 - _ptr1;
| ----- ^ ----- *const u32
| |
| *const u32
|
help: consider using `offset_from` for pointer - pointer if the pointers point to the same allocation
|
LL | let _c = unsafe { _ptr2.offset_from(_ptr1) };
| ++++++++ ~~~~~~~~~~~~~ +++
error[E0608]: cannot index into a value of type `*const u32`
--> $DIR/issue-112252-ptr-arithmetics-help.rs:9:14
|
LL | let _d = _ptr1[5];
| ^^^^^^^^
|
help: consider using `wrapping_add` or `add` for indexing into raw pointer
|
LL | let _d = _ptr1.wrapping_add(5);
| ~~~~~~~~~~~~~~ ~
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0369, E0608.
For more information about an error, try `rustc --explain E0369`.