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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,
mutability: Mutability,
) -> BlockAnd<Local>
where
M: Mirror<'tcx, Output = Expr<'tcx>>,
{
let expr = self.hir.mirror(expr);
self.expr_as_temp(block, temp_lifetime, expr, mutability)
}
fn expr_as_temp(
&mut self,
mut block: BasicBlock,
temp_lifetime: Option<region::Scope>,
expr: Expr<'tcx>,
mutability: Mutability,
) -> BlockAnd<Local> {
debug!(
"expr_as_temp(block={:?}, temp_lifetime={:?}, expr={:?}, mutability={:?})",
block, temp_lifetime, expr, mutability
);
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, mutability)
});
}
let expr_ty = expr.ty;
let temp = if mutability == Mutability::Not {
this.local_decls
.push(LocalDecl::new_immutable_temp(expr_ty, expr_span))
} else {
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)
}
}