From bd7cc779b65e658ff5b6bbd9d2bdd8ed07ea38f2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= Date: Sat, 17 Jun 2017 01:51:55 +0200 Subject: [PATCH] Make the `next` variable mutable to allow for ref mut in for patterns. --- src/librustc/hir/lowering.rs | 14 +++++++------- src/test/run-pass/for-loop-mut-ref-element.rs | 15 +++++++++++++++ 2 files changed, 22 insertions(+), 7 deletions(-) create mode 100644 src/test/run-pass/for-loop-mut-ref-element.rs diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index f2a434979535d..4b8ee8d8aecfb 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -2170,12 +2170,12 @@ impl<'a> LoweringContext<'a> { // let result = match ::std::iter::IntoIterator::into_iter() { // mut iter => { // [opt_ident]: loop { - // let next; + // let mut _next; // match ::std::iter::Iterator::next(&mut iter) { - // ::std::option::Option::Some(val) => next = val, + // ::std::option::Option::Some(val) => _next = val, // ::std::option::Option::None => break // }; - // let = next; + // let = _next; // StmtExpr(); // } // } @@ -2188,8 +2188,8 @@ impl<'a> LoweringContext<'a> { let iter = self.str_to_ident("iter"); - let next_ident = self.str_to_ident("next"); - let next_pat = self.pat_ident(e.span, next_ident); + let next_ident = self.str_to_ident("_next"); + let next_pat = self.pat_ident_binding_mode(e.span, next_ident, hir::BindByValue(hir::MutMutable)); // `::std::option::Option::Some(val) => next = val` let pat_arm = { @@ -2235,13 +2235,13 @@ impl<'a> LoweringContext<'a> { let next_expr = P(self.expr_ident(e.span, next_ident, next_pat.id)); - // `let next` + // `let mut _next` let next_let = self.stmt_let_pat(e.span, None, next_pat, hir::LocalSource::ForLoopDesugar); - // `let = next` + // `let = _next` let pat = self.lower_pat(pat); let pat_let = self.stmt_let_pat(e.span, Some(next_expr), diff --git a/src/test/run-pass/for-loop-mut-ref-element.rs b/src/test/run-pass/for-loop-mut-ref-element.rs new file mode 100644 index 0000000000000..14ce23b07242c --- /dev/null +++ b/src/test/run-pass/for-loop-mut-ref-element.rs @@ -0,0 +1,15 @@ +// 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Tests that for loops can bind elements as mutable references + +fn main() { + for ref mut _a in std::iter::once(true) {} +} \ No newline at end of file