diff options
| -rw-r--r-- | src/librustc/middle/borrowck/mod.rs | 31 | ||||
| -rw-r--r-- | src/test/compile-fail/closure-bounds-cant-mutably-borrow-with-copy.rs (renamed from src/test/compile-fail/the-case-of-the-recurring-closure-2.rs) | 0 | ||||
| -rw-r--r-- | src/test/compile-fail/moves-based-on-type-no-recursive-stack-closure.rs (renamed from src/test/compile-fail/the-case-of-the-recurring-closure.rs) | 0 | ||||
| -rw-r--r-- | src/test/compile-fail/moves-based-on-type-tuple.rs (renamed from src/test/compile-fail/move-based-on-type-tuple.rs) | 0 | ||||
| -rw-r--r-- | src/test/run-pass/closure-bounds-recursive-stack-closure.rs | 31 |
5 files changed, 55 insertions, 7 deletions
diff --git a/src/librustc/middle/borrowck/mod.rs b/src/librustc/middle/borrowck/mod.rs index 7d667c2043c..2e3813f57e0 100644 --- a/src/librustc/middle/borrowck/mod.rs +++ b/src/librustc/middle/borrowck/mod.rs @@ -538,12 +538,13 @@ impl BorrowckCtxt { move_data::MoveExpr(expr) => { let expr_ty = ty::expr_ty_adjusted(self.tcx, expr); + let suggestion = move_suggestion(self.tcx, expr_ty, + "moved by default (use `copy` to override)"); self.tcx.sess.span_note( expr.span, - fmt!("`%s` moved here because it has type `%s`, \ - which is moved by default (use `copy` to override)", + fmt!("`%s` moved here because it has type `%s`, which is %s", self.loan_path_to_str(moved_lp), - expr_ty.user_string(self.tcx))); + expr_ty.user_string(self.tcx), suggestion)); } move_data::MovePat(pat) => { @@ -557,12 +558,28 @@ impl BorrowckCtxt { } move_data::Captured(expr) => { + let expr_ty = ty::expr_ty_adjusted(self.tcx, expr); + let suggestion = move_suggestion(self.tcx, expr_ty, + "moved by default (make a copy and \ + capture that instead to override)"); self.tcx.sess.span_note( expr.span, - fmt!("`%s` moved into closure environment here \ - because its type is moved by default \ - (make a copy and capture that instead to override)", - self.loan_path_to_str(moved_lp))); + fmt!("`%s` moved into closure environment here because it \ + has type `%s`, which is %s", + self.loan_path_to_str(moved_lp), + expr_ty.user_string(self.tcx), suggestion)); + } + } + + fn move_suggestion(tcx: ty::ctxt, ty: ty::t, default_msg: &'static str) + -> &'static str { + match ty::get(ty).sty { + ty::ty_closure(ref cty) if cty.sigil == ast::BorrowedSigil => + "a non-copyable stack closure (capture it in a new closure, \ + e.g. `|x| f(x)`, to override)", + _ if !ty::type_is_copyable(tcx, ty) => + "non-copyable (perhaps you meant to use clone()?)", + _ => default_msg, } } } diff --git a/src/test/compile-fail/the-case-of-the-recurring-closure-2.rs b/src/test/compile-fail/closure-bounds-cant-mutably-borrow-with-copy.rs index bfb1e910495..bfb1e910495 100644 --- a/src/test/compile-fail/the-case-of-the-recurring-closure-2.rs +++ b/src/test/compile-fail/closure-bounds-cant-mutably-borrow-with-copy.rs diff --git a/src/test/compile-fail/the-case-of-the-recurring-closure.rs b/src/test/compile-fail/moves-based-on-type-no-recursive-stack-closure.rs index f05c30c3355..f05c30c3355 100644 --- a/src/test/compile-fail/the-case-of-the-recurring-closure.rs +++ b/src/test/compile-fail/moves-based-on-type-no-recursive-stack-closure.rs diff --git a/src/test/compile-fail/move-based-on-type-tuple.rs b/src/test/compile-fail/moves-based-on-type-tuple.rs index 6d5bb638be6..6d5bb638be6 100644 --- a/src/test/compile-fail/move-based-on-type-tuple.rs +++ b/src/test/compile-fail/moves-based-on-type-tuple.rs diff --git a/src/test/run-pass/closure-bounds-recursive-stack-closure.rs b/src/test/run-pass/closure-bounds-recursive-stack-closure.rs new file mode 100644 index 00000000000..8bb57ebaaf5 --- /dev/null +++ b/src/test/run-pass/closure-bounds-recursive-stack-closure.rs @@ -0,0 +1,31 @@ +// Copyright 2013 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. + +// Ensures that it's legal to create a recursive stack closure as long as +// its environment is copyable + +struct R<'self> { + // This struct is needed to create the + // otherwise infinite type of a fn that + // accepts itself as argument: + c: &'self fn:Copy(&R, uint) -> uint +} + +fn main() { + // Stupid version of fibonacci. + let fib: &fn:Copy(&R, uint) -> uint = |fib, x| { + if x == 0 || x == 1 { + x + } else { + (fib.c)(fib, x-1) + (fib.c)(fib, x-2) + } + }; + assert!(fib(&R { c: fib }, 7) == 13); +} |