span: Span,
expr_ty: Ty<'tcx>)
-> cmt_<'tcx> {
+ debug!(
+ "cat_rvalue_node(id={:?}, span={:?}, expr_ty={:?})",
+ id,
+ span,
+ expr_ty,
+ );
let hir_id = self.tcx.hir.node_to_hir_id(id);
let promotable = self.rvalue_promotable_map.as_ref().map(|m| m.contains(&hir_id.local_id))
.unwrap_or(false);
+ debug!(
+ "cat_rvalue_node: promotable = {:?}",
+ promotable,
+ );
+
// Always promote `[T; 0]` (even when e.g. borrowed mutably).
let promotable = match expr_ty.sty {
ty::TyArray(_, len) if len.assert_usize(self.tcx) == Some(0) => true,
_ => promotable,
};
+ debug!(
+ "cat_rvalue_node: promotable = {:?} (2)",
+ promotable,
+ );
+
// Compute maximum lifetime of this rvalue. This is 'static if
// we can promote to a constant, otherwise equal to enclosing temp
// lifetime.
span.allows_unstable();
}
}
+
+ /// While the `ExprUseVisitor` walks, we will identify which
+ /// expressions are borrowed, and insert their ids into this
+ /// table. Actually, we insert the "borrow-id", which is normally
+ /// the id of the expession being borrowed: but in the case of
+ /// `ref mut` borrows, the `id` of the pattern is
+ /// inserted. Therefore later we remove that entry from the table
+ /// and transfer it over to the value being matched. This will
+ /// then prevent said value from being promoted.
+ fn remove_mut_rvalue_borrow(&mut self, pat: &hir::Pat) -> bool {
+ let mut any_removed = false;
+ pat.walk(|p| {
+ any_removed |= self.mut_rvalue_borrows.remove(&p.id);
+ true
+ });
+ any_removed
+ }
}
impl<'a, 'tcx> Visitor<'tcx> for CheckCrateVisitor<'a, 'tcx> {
fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt) {
match stmt.node {
hir::StmtDecl(ref decl, _) => {
- match decl.node {
- hir::DeclLocal(_) => {
+ match &decl.node {
+ hir::DeclLocal(local) => {
self.promotable = false;
+
+ if self.remove_mut_rvalue_borrow(&local.pat) {
+ if let Some(init) = &local.init {
+ self.mut_rvalue_borrows.insert(init.id);
+ }
+ }
}
// Item statements are allowed
hir::DeclItem(_) => {}
// patterns and set that on the discriminator.
let mut mut_borrow = false;
for pat in arms.iter().flat_map(|arm| &arm.pats) {
- if self.mut_rvalue_borrows.remove(&pat.id) {
- mut_borrow = true;
- }
+ mut_borrow = self.remove_mut_rvalue_borrow(pat);
}
if mut_borrow {
self.mut_rvalue_borrows.insert(discr.id);
_loan_region: ty::Region<'tcx>,
bk: ty::BorrowKind,
loan_cause: euv::LoanCause) {
+ debug!(
+ "borrow(borrow_id={:?}, cmt={:?}, bk={:?}, loan_cause={:?})",
+ borrow_id,
+ cmt,
+ bk,
+ loan_cause,
+ );
+
// Kind of hacky, but we allow Unsafe coercions in constants.
// These occur when we convert a &T or *T to a *U, as well as
// when making a thin pointer (e.g., `*T`) into a fat pointer
--- /dev/null
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:15:21
+ |
+LL | fn gimme_static_mut_let() -> &'static mut u32 {
+ | _______________________________________________-
+LL | | let ref mut x = 1234543; //~ ERROR
+ | | ^^^^^^^ temporary value does not live long enough
+LL | | x
+LL | | }
+ | | -
+ | | |
+ | |_temporary value only lives until here
+ | borrow later used here
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:20:25
+ |
+LL | fn gimme_static_mut_let_nested() -> &'static mut u32 {
+ | ______________________________________________________-
+LL | | let (ref mut x, ) = (1234543, ); //~ ERROR
+ | | ^^^^^^^^^^^ temporary value does not live long enough
+LL | | x
+LL | | }
+ | | -
+ | | |
+ | |_temporary value only lives until here
+ | borrow later used here
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:25:11
+ |
+LL | match 1234543 {
+ | ^^^^^^^ temporary value does not live long enough
+...
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:31:11
+ |
+LL | match (123443,) {
+ | ^^^^^^^^^ temporary value does not live long enough
+...
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:37:10
+ |
+LL | &mut 1234543 //~ ERROR
+ | ^^^^^^^ temporary value does not live long enough
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0597`.
--- /dev/null
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test that we fail to promote the constant here which has a `ref
+// mut` borrow.
+
+fn gimme_static_mut_let() -> &'static mut u32 {
+ let ref mut x = 1234543; //~ ERROR
+ x
+}
+
+fn gimme_static_mut_let_nested() -> &'static mut u32 {
+ let (ref mut x, ) = (1234543, ); //~ ERROR
+ x
+}
+
+fn gimme_static_mut_match() -> &'static mut u32 {
+ match 1234543 {
+ ref mut x => x //~ ERROR
+ }
+}
+
+fn gimme_static_mut_match_nested() -> &'static mut u32 {
+ match (123443,) {
+ (ref mut x,) => x, //~ ERROR
+ }
+}
+
+fn gimme_static_mut_ampersand() -> &'static mut u32 {
+ &mut 1234543 //~ ERROR
+}
+
+fn main() {
+}
--- /dev/null
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:15:9
+ |
+LL | let ref mut x = 1234543; //~ ERROR
+ | ^^^^^^^^^ temporary value does not live long enough
+LL | x
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:20:10
+ |
+LL | let (ref mut x, ) = (1234543, ); //~ ERROR
+ | ^^^^^^^^^ borrowed value does not live long enough
+LL | x
+LL | }
+ | - borrowed value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:26:9
+ |
+LL | ref mut x => x //~ ERROR
+ | ^^^^^^^^^ temporary value does not live long enough
+LL | }
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:32:10
+ |
+LL | (ref mut x,) => x, //~ ERROR
+ | ^^^^^^^^^ borrowed value does not live long enough
+LL | }
+LL | }
+ | - borrowed value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/promote-ref-mut-in-let-issue-46557.rs:37:10
+ |
+LL | &mut 1234543 //~ ERROR
+ | ^^^^^^^ temporary value does not live long enough
+LL | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for the static lifetime...
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0597`.
projects / rust.git / commitdiff