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use build::{BlockAnd, BlockAndExtension, Builder};
use hair::*;
use rustc::middle::region;
use rustc::mir::*;
impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
pub fn as_temp<M>(&mut self,
block: BasicBlock,
temp_lifetime: Option<region::Scope>,
expr: M)
-> BlockAnd<Local>
where M: Mirror<'tcx, Output = Expr<'tcx>>
{
let expr = self.hir.mirror(expr);
self.expr_as_temp(block, temp_lifetime, expr)
}
fn expr_as_temp(&mut self,
mut block: BasicBlock,
temp_lifetime: Option<region::Scope>,
expr: Expr<'tcx>)
-> BlockAnd<Local> {
debug!("expr_as_temp(block={:?}, temp_lifetime={:?}, expr={:?})",
block, temp_lifetime, expr);
let this = self;
let expr_span = expr.span;
let source_info = this.source_info(expr_span);
if let ExprKind::Scope { region_scope, lint_level, value } = expr.kind {
return this.in_scope((region_scope, source_info), lint_level, block, |this| {
this.as_temp(block, temp_lifetime, value)
});
}
let expr_ty = expr.ty;
let temp = this.local_decls.push(LocalDecl::new_temp(expr_ty, expr_span));
if !expr_ty.is_never() {
this.cfg.push(block, Statement {
source_info,
kind: StatementKind::StorageLive(temp)
});
}
unpack!(block = this.into(&Place::Local(temp), block, expr));
if let Some(temp_lifetime) = temp_lifetime {
this.schedule_drop_storage_and_value(
expr_span, temp_lifetime, &Place::Local(temp), expr_ty,
);
}
block.and(temp)
}
}