diff options
7 files changed, 129 insertions, 25 deletions
diff --git a/src/librustc/middle/expr_use_visitor.rs b/src/librustc/middle/expr_use_visitor.rs index 78a9e406c95..8ada67efaaf 100644 --- a/src/librustc/middle/expr_use_visitor.rs +++ b/src/librustc/middle/expr_use_visitor.rs @@ -82,6 +82,9 @@ pub trait Delegate<'tcx> { assignment_span: Span, assignee_cmt: &mc::cmt_<'tcx>, mode: MutateMode); + + // A nested closure or generator - only one layer deep. + fn nested_body(&mut self, _body_id: hir::BodyId) {} } #[derive(Copy, Clone, PartialEq, Debug)] @@ -531,8 +534,9 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> { self.consume_expr(&base); } - hir::ExprKind::Closure(.., fn_decl_span, _) => { - self.walk_captures(expr, fn_decl_span) + hir::ExprKind::Closure(_, _, body_id, fn_decl_span, _) => { + self.delegate.nested_body(body_id); + self.walk_captures(expr, fn_decl_span); } hir::ExprKind::Box(ref base) => { diff --git a/src/librustc_borrowck/borrowck/gather_loans/mod.rs b/src/librustc_borrowck/borrowck/gather_loans/mod.rs index bf730ba41f4..1e3364ecb9a 100644 --- a/src/librustc_borrowck/borrowck/gather_loans/mod.rs +++ b/src/librustc_borrowck/borrowck/gather_loans/mod.rs @@ -153,6 +153,24 @@ impl<'a, 'tcx> euv::Delegate<'tcx> for GatherLoanCtxt<'a, 'tcx> { .node_type(id); gather_moves::gather_decl(self.bccx, &self.move_data, id, ty); } + + fn nested_body(&mut self, body_id: hir::BodyId) { + debug!("nested_body(body_id={:?})", body_id); + // rust-lang/rust#58776: MIR and AST borrow check disagree on where + // certain closure errors are reported. As such migrate borrowck has to + // operate at the level of items, rather than bodies. Check if the + // contained closure had any errors and set `signalled_any_error` if it + // has. + let bccx = self.bccx; + if bccx.tcx.migrate_borrowck() { + if let SignalledError::NoErrorsSeen = bccx.signalled_any_error.get() { + let closure_def_id = bccx.tcx.hir().body_owner_def_id(body_id); + debug!("checking closure: {:?}", closure_def_id); + + bccx.signalled_any_error.set(bccx.tcx.borrowck(closure_def_id).signalled_any_error); + } + } + } } /// Implements the A-* rules in README.md. diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs index d5dfdf0add5..0bdf44c2ae0 100644 --- a/src/librustc_mir/borrow_check/mod.rs +++ b/src/librustc_mir/borrow_check/mod.rs @@ -329,30 +329,12 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>( // When borrowck=migrate, check if AST-borrowck would // error on the given code. - // rust-lang/rust#55492: loop over parents to ensure that - // errors that AST-borrowck only detects in some parent of - // a closure still allows NLL to signal an error. - let mut curr_def_id = def_id; - let signalled_any_error = loop { - match tcx.borrowck(curr_def_id).signalled_any_error { - SignalledError::NoErrorsSeen => { - // keep traversing (and borrow-checking) parents - } - SignalledError::SawSomeError => { - // stop search here - break SignalledError::SawSomeError; - } - } - - if tcx.is_closure(curr_def_id) { - curr_def_id = tcx.parent_def_id(curr_def_id) - .expect("a closure must have a parent_def_id"); - } else { - break SignalledError::NoErrorsSeen; - } - }; + // rust-lang/rust#55492, rust-lang/rust#58776 check the base def id + // for errors. AST borrowck is responsible for aggregating + // `signalled_any_error` from all of the nested closures here. + let base_def_id = tcx.closure_base_def_id(def_id); - match signalled_any_error { + match tcx.borrowck(base_def_id).signalled_any_error { SignalledError::NoErrorsSeen => { // if AST-borrowck signalled no errors, then // downgrade all the buffered MIR-borrowck errors diff --git a/src/test/ui/borrowck/issue-58776-borrowck-scans-children.ast.stderr b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.ast.stderr new file mode 100644 index 00000000000..9e0b0aac1e3 --- /dev/null +++ b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.ast.stderr @@ -0,0 +1,15 @@ +error[E0597]: `**greeting` does not live long enough + --> $DIR/issue-58776-borrowck-scans-children.rs:10:24 + | +LL | let res = (|| (|| &greeting)())(); + | -- ^^^^^^^^ - borrowed value only lives until here + | | | + | | borrowed value does not live long enough + | capture occurs here +... +LL | } + | - borrowed value needs to live until here + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0597`. diff --git a/src/test/ui/borrowck/issue-58776-borrowck-scans-children.migrate.stderr b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.migrate.stderr new file mode 100644 index 00000000000..bd8f2286f17 --- /dev/null +++ b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.migrate.stderr @@ -0,0 +1,32 @@ +error[E0506]: cannot assign to `greeting` because it is borrowed + --> $DIR/issue-58776-borrowck-scans-children.rs:13:5 + | +LL | let res = (|| (|| &greeting)())(); + | -- -------- borrow occurs due to use in closure + | | + | borrow of `greeting` occurs here +... +LL | greeting = "DEALLOCATED".to_string(); + | ^^^^^^^^ assignment to borrowed `greeting` occurs here +... +LL | println!("thread result: {:?}", res); + | --- borrow later used here + +error[E0505]: cannot move out of `greeting` because it is borrowed + --> $DIR/issue-58776-borrowck-scans-children.rs:16:10 + | +LL | let res = (|| (|| &greeting)())(); + | -- -------- borrow occurs due to use in closure + | | + | borrow of `greeting` occurs here +... +LL | drop(greeting); + | ^^^^^^^^ move out of `greeting` occurs here +... +LL | println!("thread result: {:?}", res); + | --- borrow later used here + +error: aborting due to 2 previous errors + +Some errors occurred: E0505, E0506. +For more information about an error, try `rustc --explain E0505`. diff --git a/src/test/ui/borrowck/issue-58776-borrowck-scans-children.nll.stderr b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.nll.stderr new file mode 100644 index 00000000000..bd8f2286f17 --- /dev/null +++ b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.nll.stderr @@ -0,0 +1,32 @@ +error[E0506]: cannot assign to `greeting` because it is borrowed + --> $DIR/issue-58776-borrowck-scans-children.rs:13:5 + | +LL | let res = (|| (|| &greeting)())(); + | -- -------- borrow occurs due to use in closure + | | + | borrow of `greeting` occurs here +... +LL | greeting = "DEALLOCATED".to_string(); + | ^^^^^^^^ assignment to borrowed `greeting` occurs here +... +LL | println!("thread result: {:?}", res); + | --- borrow later used here + +error[E0505]: cannot move out of `greeting` because it is borrowed + --> $DIR/issue-58776-borrowck-scans-children.rs:16:10 + | +LL | let res = (|| (|| &greeting)())(); + | -- -------- borrow occurs due to use in closure + | | + | borrow of `greeting` occurs here +... +LL | drop(greeting); + | ^^^^^^^^ move out of `greeting` occurs here +... +LL | println!("thread result: {:?}", res); + | --- borrow later used here + +error: aborting due to 2 previous errors + +Some errors occurred: E0505, E0506. +For more information about an error, try `rustc --explain E0505`. diff --git a/src/test/ui/borrowck/issue-58776-borrowck-scans-children.rs b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.rs new file mode 100644 index 00000000000..378969f9a18 --- /dev/null +++ b/src/test/ui/borrowck/issue-58776-borrowck-scans-children.rs @@ -0,0 +1,21 @@ +// ignore-compare-mode-nll + +// revisions: ast migrate nll + +//[migrate]compile-flags: -Z borrowck=migrate +#![cfg_attr(nll, feature(nll))] + +fn main() { + let mut greeting = "Hello world!".to_string(); + let res = (|| (|| &greeting)())(); + //[ast]~^ ERROR does not live long enough + + greeting = "DEALLOCATED".to_string(); + //[migrate]~^ ERROR cannot assign + //[nll]~^^ ERROR cannot assign + drop(greeting); + //[migrate]~^ ERROR cannot move + //[nll]~^^ ERROR cannot move + + println!("thread result: {:?}", res); +} |