Auto merge of #104889 - GuillaumeGomez:fix-impl-block-in-const-expr, r=notriddle

[rust.git] / compiler / rustc_mir_transform / src / cleanup_post_borrowck.rs

diff --git a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
index fe5295afaced711959a5d705790908d46e1ca43c..d435d3ee69b76a94eda4fe73a4ff40d60eb8aa0d 100644 (file)
--- a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
+++ b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
@@ -1,32 +1,26 @@
-//! This module provides a pass to replacing the following statements with
-//! [`Nop`]s
+//! This module provides a pass that removes parts of MIR that are no longer relevant after
+//! analysis phase and borrowck. In particular, it removes false edges, user type annotations and
+//! replaces following statements with [`Nop`]s:
 //!
 //!   - [`AscribeUserType`]
 //!   - [`FakeRead`]
 //!   - [`Assign`] statements with a [`Shallow`] borrow
 //!
-//! The `CleanFakeReadsAndBorrows` "pass" is actually implemented as two
-//! traversals (aka visits) of the input MIR. The first traversal,
-//! `DeleteAndRecordFakeReads`, deletes the fake reads and finds the
-//! temporaries read by [`ForMatchGuard`] reads, and `DeleteFakeBorrows`
-//! deletes the initialization of those temporaries.
-//!
 //! [`AscribeUserType`]: rustc_middle::mir::StatementKind::AscribeUserType
-//! [`Shallow`]: rustc_middle::mir::BorrowKind::Shallow
-//! [`FakeRead`]: rustc_middle::mir::StatementKind::FakeRead
 //! [`Assign`]: rustc_middle::mir::StatementKind::Assign
-//! [`ForMatchGuard`]: rustc_middle::mir::FakeReadCause::ForMatchGuard
+//! [`FakeRead`]: rustc_middle::mir::StatementKind::FakeRead
 //! [`Nop`]: rustc_middle::mir::StatementKind::Nop
+//! [`Shallow`]: rustc_middle::mir::BorrowKind::Shallow
 
 use crate::MirPass;
-use rustc_middle::mir::{Body, BorrowKind, Rvalue, StatementKind};
+use rustc_middle::mir::{Body, BorrowKind, Rvalue, StatementKind, TerminatorKind};
 use rustc_middle::ty::TyCtxt;
 
 pub struct CleanupPostBorrowck;
 
 impl<'tcx> MirPass<'tcx> for CleanupPostBorrowck {
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        for basic_block in body.basic_blocks.as_mut_preserves_cfg() {
+        for basic_block in body.basic_blocks.as_mut() {
             for statement in basic_block.statements.iter_mut() {
                 match statement.kind {
                     StatementKind::AscribeUserType(..)
@@ -35,6 +29,14 @@ fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
                     _ => (),
                 }
             }
+            let terminator = basic_block.terminator_mut();
+            match terminator.kind {
+                TerminatorKind::FalseEdge { real_target, .. }
+                | TerminatorKind::FalseUnwind { real_target, .. } => {
+                    terminator.kind = TerminatorKind::Goto { target: real_target };
+                }
+                _ => {}
+            }
         }
 
         body.user_type_annotations.raw.clear();