From 3322595e896e95c3e19ca33c854ad529f2ef3c19 Mon Sep 17 00:00:00 2001 From: Niko Matsakis Date: Mon, 1 Apr 2013 22:32:37 -0700 Subject: Reason about nested free variables that appear in a function signature. In a nutshell, the idea is to (1) report an error if, for a region pointer `'a T`, the lifetime `'a` is longer than any lifetimes that appear in `T` (in other words, if a borrowed pointer outlives any portion of its contents) and then (2) use this to assume that in a function like `fn(self: &'a &'b T)`, the relationship `'a <= 'b` holds. This is needed for #5656. Fixes #5728. --- .../compile-fail/kindck-owned-trait-contains.rs | 3 +- .../regions-escape-via-trait-or-not.rs | 4 +-- .../regions-free-region-ordering-callee.rs | 37 ++++++++++++++++++++ .../regions-free-region-ordering-caller.rs | 40 ++++++++++++++++++++++ src/test/compile-fail/regions-trait-2.rs | 8 ++++- 5 files changed, 88 insertions(+), 4 deletions(-) create mode 100644 src/test/compile-fail/regions-free-region-ordering-callee.rs create mode 100644 src/test/compile-fail/regions-free-region-ordering-caller.rs (limited to 'src/test') diff --git a/src/test/compile-fail/kindck-owned-trait-contains.rs b/src/test/compile-fail/kindck-owned-trait-contains.rs index f5153265308..54ee8bcc70e 100644 --- a/src/test/compile-fail/kindck-owned-trait-contains.rs +++ b/src/test/compile-fail/kindck-owned-trait-contains.rs @@ -27,5 +27,6 @@ fn main() { let x: &'blk int = &3; repeater(@x) }; - assert!(3 == *(y.get())); //~ ERROR reference is not valid + assert!(3 == *(y.get())); //~ ERROR dereference of reference outside its lifetime + //~^ ERROR reference is not valid outside of its lifetime } diff --git a/src/test/compile-fail/regions-escape-via-trait-or-not.rs b/src/test/compile-fail/regions-escape-via-trait-or-not.rs index fb9d963dc80..f7165784c79 100644 --- a/src/test/compile-fail/regions-escape-via-trait-or-not.rs +++ b/src/test/compile-fail/regions-escape-via-trait-or-not.rs @@ -24,9 +24,9 @@ fn with(f: &fn(x: &int) -> R) -> int { fn return_it() -> int { with(|o| o) - //~^ ERROR reference is not valid outside of its lifetime + //~^ ERROR cannot infer an appropriate lifetime due to conflicting requirements //~^^ ERROR reference is not valid outside of its lifetime - //~^^^ ERROR cannot infer an appropriate lifetime + //~^^^ ERROR reference is not valid outside of its lifetime } fn main() { diff --git a/src/test/compile-fail/regions-free-region-ordering-callee.rs b/src/test/compile-fail/regions-free-region-ordering-callee.rs new file mode 100644 index 00000000000..e5399fc7fa3 --- /dev/null +++ b/src/test/compile-fail/regions-free-region-ordering-callee.rs @@ -0,0 +1,37 @@ +// Copyright 2012 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 callees correctly infer an ordering between free regions +// that appear in their parameter list. See also +// regions-free-region-ordering-caller.rs + +fn ordering1<'a, 'b>(x: &'a &'b uint) -> &'a uint { + // It is safe to assume that 'a <= 'b due to the type of x + let y: &'b uint = &**x; + return y; +} + +fn ordering2<'a, 'b>(x: &'a &'b uint, y: &'a uint) -> &'b uint { + // However, it is not safe to assume that 'b <= 'a + &*y //~ ERROR cannot infer an appropriate lifetime +} + +fn ordering3<'a, 'b>(x: &'a uint, y: &'b uint) -> &'a &'b uint { + // Do not infer an ordering from the return value. + let z: &'b uint = &*x; + //~^ ERROR cannot infer an appropriate lifetime due to conflicting requirements + fail!(); +} + +fn ordering4<'a, 'b>(a: &'a uint, b: &'b uint, x: &fn(&'a &'b uint)) { + let z: Option<&'a &'b uint> = None; +} + +fn main() {} \ No newline at end of file diff --git a/src/test/compile-fail/regions-free-region-ordering-caller.rs b/src/test/compile-fail/regions-free-region-ordering-caller.rs new file mode 100644 index 00000000000..d06dcd8aa86 --- /dev/null +++ b/src/test/compile-fail/regions-free-region-ordering-caller.rs @@ -0,0 +1,40 @@ +// Copyright 2012 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. + +// Test various ways to construct a pointer with a longer lifetime +// than the thing it points at and ensure that they result in +// errors. See also regions-free-region-ordering-callee.rs + +struct Paramd<'self> { x: &'self uint } + +fn call1<'a>(x: &'a uint) { + let y: uint = 3; + let z: &'a &'blk uint = &(&y); + //~^ ERROR pointer has a longer lifetime than the data it references +} + +fn call2<'a, 'b>(a: &'a uint, b: &'b uint) { + let z: Option<&'b &'a uint> = None; + //~^ ERROR pointer has a longer lifetime than the data it references +} + +fn call3<'a, 'b>(a: &'a uint, b: &'b uint) { + let y: Paramd<'a> = Paramd { x: a }; + let z: Option<&'b Paramd<'a>> = None; + //~^ ERROR pointer has a longer lifetime than the data it references +} + +fn call4<'a, 'b>(a: &'a uint, b: &'b uint) { + let z: Option<&fn(&'a &'b uint)> = None; + //~^ ERROR pointer has a longer lifetime than the data it references +} + + +fn main() {} \ No newline at end of file diff --git a/src/test/compile-fail/regions-trait-2.rs b/src/test/compile-fail/regions-trait-2.rs index 5811496cab4..9855a234618 100644 --- a/src/test/compile-fail/regions-trait-2.rs +++ b/src/test/compile-fail/regions-trait-2.rs @@ -8,6 +8,11 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. +// xfail-test #5723 + +// Test that you cannot escape a borrowed pointer +// into a trait. + struct ctxt { v: uint } trait get_ctxt { @@ -24,8 +29,9 @@ fn make_gc() -> @get_ctxt { let ctxt = ctxt { v: 22u }; let hc = has_ctxt { c: &ctxt }; return @hc as @get_ctxt; + //^~ ERROR source contains borrowed pointer } fn main() { - make_gc().get_ctxt().v; //~ ERROR illegal borrow + make_gc().get_ctxt().v; } -- cgit 1.4.1-3-g733a5