From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- src/test/ui/borrowck/two-phase-nonrecv-autoref.rs | 166 ++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 src/test/ui/borrowck/two-phase-nonrecv-autoref.rs (limited to 'src/test/ui/borrowck/two-phase-nonrecv-autoref.rs') diff --git a/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs b/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs new file mode 100644 index 000000000..3d395d1f2 --- /dev/null +++ b/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs @@ -0,0 +1,166 @@ +// revisions: base + +//[g2p]compile-flags: -Z two-phase-beyond-autoref +// the above revision is disabled until two-phase-beyond-autoref support is better + +// This is a test checking that when we limit two-phase borrows to +// method receivers, we do not let other kinds of auto-ref to leak +// through. +// +// The g2p revision illustrates the "undesirable" behavior you would +// otherwise observe without limiting the phasing to autoref on method +// receivers (namely, in many cases demonstrated below, the error +// would not arise). + +use std::ops::{Index, IndexMut}; + +fn foo(x: &mut u32, y: u32) { + *x += y; +} + +fn deref_coercion(x: &mut u32) { + foo(x, *x); + // Above error is a known limitation of AST borrowck +} + +// While adding a flag to adjustments (indicating whether they +// should support two-phase borrows, here are the cases I +// encountered: +// +// - [x] Resolving overloaded_call_traits (call, call_mut, call_once) +// - [x] deref_coercion (shown above) +// - [x] coerce_unsized e.g., `&[T; n]`, `&mut [T; n] -> &[T]`, +// `&mut [T; n] -> &mut [T]`, `&Concrete -> &Trait` +// - [x] Method Call Receivers (the case we want to support!) +// - [x] ExprKind::Index and ExprKind::Unary Deref; only need to handle coerce_index_op +// - [x] overloaded_binops + +fn overloaded_call_traits() { + // Regarding overloaded call traits, note that there is no + // scenario where adding two-phase borrows should "fix" these + // cases, because either we will resolve both invocations to + // `call_mut` (in which case the inner call requires a mutable + // borrow which will conflict with the outer reservation), or we + // will resolve both to `call` (which will just work, regardless + // of two-phase borrow support), or we will resolve both to + // `call_once` (in which case the inner call requires moving the + // receiver, invalidating the outer call). + + fn twice_ten_sm i32>(f: &mut F) { + f(f(10)); + //~^ ERROR cannot borrow `*f` as mutable more than once at a time + } + fn twice_ten_si i32>(f: &mut F) { + f(f(10)); + } + fn twice_ten_so i32>(f: Box) { + f(f(10)); + //~^ ERROR use of moved value: `f` + } + + fn twice_ten_om(f: &mut dyn FnMut(i32) -> i32) { + f(f(10)); + //~^ ERROR cannot borrow `*f` as mutable more than once at a time + } + fn twice_ten_oi(f: &mut dyn Fn(i32) -> i32) { + f(f(10)); + } + fn twice_ten_oo(f: Box i32>) { + f(f(10)); + //~^ ERROR use of moved value: `f` + } + + twice_ten_sm(&mut |x| x + 1); + twice_ten_si(&mut |x| x + 1); + twice_ten_so(Box::new(|x| x + 1)); + twice_ten_om(&mut |x| x + 1); + twice_ten_oi(&mut |x| x + 1); + twice_ten_oo(Box::new(|x| x + 1)); +} + +trait TwoMethods { + fn m(&mut self, x: i32) -> i32 { x + 1 } + fn i(&self, x: i32) -> i32 { x + 1 } +} + +struct T; + +impl TwoMethods for T { } + +struct S; + +impl S { + fn m(&mut self, x: i32) -> i32 { x + 1 } + fn i(&self, x: i32) -> i32 { x + 1 } +} + +impl TwoMethods for [i32; 3] { } + +fn double_access(m: &mut [X], s: &[X]) { + m[0] = s[1]; +} + +fn coerce_unsized() { + let mut a = [1, 2, 3]; + + // This is not okay. + double_access(&mut a, &a); + //~^ ERROR cannot borrow `a` as immutable because it is also borrowed as mutable [E0502] + + // But this is okay. + a.m(a.i(10)); + // Above error is an expected limitation of AST borrowck +} + +struct I(i32); + +impl Index for I { + type Output = i32; + fn index(&self, _: i32) -> &i32 { + &self.0 + } +} + +impl IndexMut for I { + fn index_mut(&mut self, _: i32) -> &mut i32 { + &mut self.0 + } +} + +fn coerce_index_op() { + let mut i = I(10); + i[i[3]] = 4; + //~^ ERROR cannot borrow `i` as immutable because it is also borrowed as mutable [E0502] + // Shoud be accepted with g2p + + i[3] = i[4]; + + i[i[3]] = i[4]; + //~^ ERROR cannot borrow `i` as immutable because it is also borrowed as mutable [E0502] + // Shoud be accepted with g2p +} + +fn main() { + + // As a reminder, this is the basic case we want to ensure we handle. + let mut v = vec![1, 2, 3]; + v.push(v.len()); + // Error above is an expected limitation of AST borrowck + + // (as a rule, pnkfelix does not like to write tests with dead code.) + + deref_coercion(&mut 5); + overloaded_call_traits(); + + + let mut s = S; + s.m(s.i(10)); + // Error above is an expected limitation of AST borrowck + + let mut t = T; + t.m(t.i(10)); + // Error above is an expected limitation of AST borrowck + + coerce_unsized(); + coerce_index_op(); +} -- cgit v1.2.3