diff options
| -rw-r--r-- | components/plugins/lints.rs | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/components/plugins/lints.rs b/components/plugins/lints.rs index cbae26eb2b2..61394651b1f 100644 --- a/components/plugins/lints.rs +++ b/components/plugins/lints.rs @@ -31,7 +31,7 @@ pub struct TransmutePass; /// /// - Not being used in a struct/enum field which is not `#[must_root]` itself /// - Not being used as an argument to a function (Except onces named `new` and `new_inherited`) -/// - Not being bound locally in a `let` statement. +/// - Not being bound locally in a `let` statement, assignment, `for` loop, or `match` statement. /// /// This helps catch most situations where pointers like `JS<T>` are used in a way that they can be invalidated by a GC pass. pub struct UnrootedPass; @@ -142,19 +142,32 @@ impl LintPass for UnrootedPass { } // Partially copied from rustc::middle::lint::builtin - // Catches `let` statements which store a #[must_root] value - // Expressions which return out of blocks eventually end up in a `let` + // Catches `let` statements and assignments which store a #[must_root] value + // Expressions which return out of blocks eventually end up in a `let` or assignment // statement or a function return (which will be caught when it is used elsewhere) fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) { - // Catch the let binding let expr = match s.node { + // Catch a `let` binding ast::StmtDecl(ref decl, _) => match decl.node { ast::DeclLocal(ref loc) => match loc.init { - Some(ref e) => &**e, - _ => return + Some(ref e) => &**e, + _ => return }, _ => return }, + ast::StmtExpr(ref expr, _) => match expr.node { + // This catches deferred `let` statements + ast::ExprAssign(_, ref e) | + // Match statements allow you to bind onto the variable later in an arm + // We need not check arms individually since enum/struct fields are already + // linted in `check_struct_def` and `check_variant ` + // (so there is no way of destructuring out a `#[must_root]` field) + ast::ExprMatch(ref e, _) | + // For loops allow you to bind a return value locally + ast::ExprForLoop(_, ref e, _, _) => &**e, + // XXXManishearth look into `if let` once it lands in our rustc + _ => return + }, _ => return }; |