diff options
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/into.rs | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs index 7e1a066e105..69f3d3101fa 100644 --- a/compiler/rustc_mir_build/src/build/expr/into.rs +++ b/compiler/rustc_mir_build/src/build/expr/into.rs @@ -66,6 +66,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { (if_then_scope, then_source_info), LintLevel::Inherited, |this| { + // FIXME: Does this need extra logic to handle let-chains? let source_info = if this.is_let(cond) { let variable_scope = this.new_source_scope(then_span, LintLevel::Inherited, None); @@ -74,6 +75,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { } else { this.source_info(then_span) }; + + // Lower the condition, and have it branch into `then` and `else` blocks. let (then_block, else_block) = this.in_if_then_scope(condition_scope, then_span, |this| { let then_blk = unpack!(this.then_else_break( @@ -85,8 +88,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { true, // Declare `let` bindings normally )); + // Lower the `then` arm into its block. this.expr_into_dest(destination, then_blk, then) }); + + // Pack `(then_block, else_block)` into `BlockAnd<BasicBlock>`. then_block.and(else_block) }, ); @@ -105,6 +111,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { this.cfg.push_assign_unit(else_blk, correct_si, destination, this.tcx); } + // The `then` and `else` arms have been lowered into their respective + // blocks, so make both of them meet up in a new block. let join_block = this.cfg.start_new_block(); this.cfg.goto(then_blk, source_info, join_block); this.cfg.goto(else_blk, source_info, join_block); |