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account temporary borrow by raw-ptr

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This commit is contained in:
csmoe 2020-01-19 12:59:15 +08:00
parent 2480c9eac1
commit 42b6ed13be
1 changed files with 32 additions and 5 deletions
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37
src/librustc/traits/error_reporting/suggestions.rs
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@ -13,6 +13,7 @@ use rustc_errors::{
};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_hir::def::DefKind;
use rustc_hir::intravisit::Visitor;
use rustc_hir::Node;
use rustc_span::source_map::SourceMap;
@ -1366,14 +1367,40 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
if let Some(expr_id) = expr {
let expr = hir.expect_expr(expr_id);
let is_ref = tables.expr_adjustments(expr).iter().any(|adj| adj.is_region_borrow());
debug!("target_ty evaluated from {:?}", expr);
let parent = hir.get_parent_node(expr_id);
if let Some(hir::Node::Expr(e)) = hir.find(parent) {
let method_span = hir.span(parent);
if tables.is_method_call(e) && is_ref {
let parent_span = hir.span(parent);
let parent_did = parent.owner_def_id();
// ```rust
// impl T {
// fn foo(&self) -> i32 {}
// }
// T.foo();
// ^^^^^^^ a temporary `&T` created inside this method call due to `&self`
// ```
//
let is_region_borrow =
tables.expr_adjustments(expr).iter().any(|adj| adj.is_region_borrow());
// ```rust
// struct Foo(*const u8);
// bar(Foo(std::ptr::null())).await;
// ^^^^^^^^^^^^^^^^^^^^^ raw-ptr `*T` created inside this struct ctor.
// ```
debug!("parent_def_kind: {:?}", self.tcx.def_kind(parent_did));
let is_raw_borrow_inside_fn_like_call = match self.tcx.def_kind(parent_did) {
Some(DefKind::Fn) | Some(DefKind::Ctor(..)) => target_ty.is_unsafe_ptr(),
_ => false,
};
if (tables.is_method_call(e) && is_region_borrow)
|| is_raw_borrow_inside_fn_like_call
{
err.span_help(
method_span,
"consider moving this method call into a `let` \
parent_span,
"consider moving this into a `let` \
binding to create a shorter lived borrow",
);
}