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Fix diagnostic issue when using FakeReads in closures

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This commit is contained in:
Roxane 2021-03-25 23:03:12 -04:00
parent 138fd56cf9
commit 2fb1fb7634
31 changed files with 119 additions and 80 deletions
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16
compiler/rustc_middle/src/mir/mod.rs
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@ -1452,7 +1452,7 @@ pub struct Statement<'tcx> {
// `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
static_assert_size!(Statement<'_>, 32);
static_assert_size!(Statement<'_>, 40);
impl Statement<'_> {
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
@ -1575,7 +1575,12 @@ pub enum FakeReadCause {
/// `let x: !; match x {}` doesn't generate any read of x so we need to
/// generate a read of x to check that it is initialized and safe.
ForMatchedPlace,
///
/// If a closure pattern matches a Place starting with an Upvar, then we introduce a
/// FakeRead for that Place outside the closure, in such a case this option would be
/// Some(closure_def_id).
/// Otherwise, the value of the optional DefId will be None.
ForMatchedPlace(Option<DefId>),
/// A fake read of the RefWithinGuard version of a bind-by-value variable
/// in a match guard to ensure that it's value hasn't change by the time
@ -1594,7 +1599,12 @@ pub enum FakeReadCause {
/// but in some cases it can affect the borrow checker, as in #53695.
/// Therefore, we insert a "fake read" here to ensure that we get
/// appropriate errors.
ForLet,
///
/// If a closure pattern matches a Place starting with an Upvar, then we introduce a
/// FakeRead for that Place outside the closure, in such a case this option would be
/// Some(closure_def_id).
/// Otherwise, the value of the optional DefId will be None.
ForLet(Option<DefId>),
/// If we have an index expression like
///