mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-02 07:22:42 +00:00
Use as_temp
to evaluate statement expressions
This commit is contained in:
parent
62bec71446
commit
101a2f59b4
@ -78,7 +78,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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let source_info = this.source_info(span);
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for stmt in stmts {
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let Stmt { kind, opt_destruction_scope, span: stmt_span } = this.hir.mirror(stmt);
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let Stmt { kind, opt_destruction_scope } = this.hir.mirror(stmt);
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match kind {
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StmtKind::Expr { scope, expr } => {
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this.block_context.push(BlockFrame::Statement { ignores_expr_result: true });
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@ -87,7 +87,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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let si = (scope, source_info);
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this.in_scope(si, LintLevel::Inherited, |this| {
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let expr = this.hir.mirror(expr);
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this.stmt_expr(block, expr, Some(stmt_span))
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this.stmt_expr(block, expr, Some(scope))
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})
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}));
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}
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@ -1,6 +1,7 @@
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use crate::build::scope::BreakableScope;
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use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
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use crate::hair::*;
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use rustc::middle::region;
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use rustc::mir::*;
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impl<'a, 'tcx> Builder<'a, 'tcx> {
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@ -8,14 +9,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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/// If the original expression was an AST statement,
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/// (e.g., `some().code(&here());`) then `opt_stmt_span` is the
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/// span of that statement (including its semicolon, if any).
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/// Diagnostics use this span (which may be larger than that of
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/// `expr`) to identify when statement temporaries are dropped.
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pub fn stmt_expr(&mut self,
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mut block: BasicBlock,
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expr: Expr<'tcx>,
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opt_stmt_span: Option<StatementSpan>)
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-> BlockAnd<()>
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{
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/// The scope is used if a statement temporary must be dropped.
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pub fn stmt_expr(
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&mut self,
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mut block: BasicBlock,
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expr: Expr<'tcx>,
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statement_scope: Option<region::Scope>,
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) -> BlockAnd<()> {
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let this = self;
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let expr_span = expr.span;
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let source_info = this.source_info(expr.span);
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@ -30,7 +30,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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} => {
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let value = this.hir.mirror(value);
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this.in_scope((region_scope, source_info), lint_level, |this| {
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this.stmt_expr(block, value, opt_stmt_span)
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this.stmt_expr(block, value, statement_scope)
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})
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}
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ExprKind::Assign { lhs, rhs } => {
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@ -199,7 +199,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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block.unit()
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}
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_ => {
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let expr_ty = expr.ty;
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assert!(
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statement_scope.is_some(),
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"Should not be calling `stmt_expr` on a general expression \
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without a statement scope",
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);
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// Issue #54382: When creating temp for the value of
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// expression like:
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@ -208,48 +212,34 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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//
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// it is usually better to focus on `the_value` rather
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// than the entirety of block(s) surrounding it.
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let mut temp_span = expr_span;
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let mut temp_in_tail_of_block = false;
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if let ExprKind::Block { body } = expr.kind {
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if let Some(tail_expr) = &body.expr {
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let mut expr = tail_expr;
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while let rustc::hir::ExprKind::Block(subblock, _label) = &expr.node {
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if let Some(subtail_expr) = &subblock.expr {
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expr = subtail_expr
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} else {
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break;
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let adjusted_span = (|| {
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if let ExprKind::Block { body } = expr.kind {
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if let Some(tail_expr) = &body.expr {
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let mut expr = tail_expr;
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while let rustc::hir::ExprKind::Block(subblock, _label) = &expr.node {
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if let Some(subtail_expr) = &subblock.expr {
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expr = subtail_expr
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} else {
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break;
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}
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}
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}
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temp_span = expr.span;
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temp_in_tail_of_block = true;
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}
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}
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let temp = {
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let mut local_decl = LocalDecl::new_temp(expr.ty.clone(), temp_span);
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if temp_in_tail_of_block {
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if this.block_context.currently_ignores_tail_results() {
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local_decl = local_decl.block_tail(BlockTailInfo {
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this.block_context.push(BlockFrame::TailExpr {
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tail_result_is_ignored: true
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});
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return Some(expr.span);
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}
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}
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let temp = this.local_decls.push(local_decl);
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let place = Place::from(temp);
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debug!("created temp {:?} for expr {:?} in block_context: {:?}",
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temp, expr, this.block_context);
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place
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};
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unpack!(block = this.into(&temp, block, expr));
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None
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})();
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// Attribute drops of the statement's temps to the
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// semicolon at the statement's end.
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let drop_point = this.hir.tcx().sess.source_map().end_point(match opt_stmt_span {
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None => expr_span,
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Some(StatementSpan(span)) => span,
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});
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let temp = unpack!(block =
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this.as_temp(block, statement_scope, expr, Mutability::Not));
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if let Some(span) = adjusted_span {
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this.local_decls[temp].source_info.span = span;
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this.block_context.pop();
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}
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unpack!(block = this.build_drop(block, drop_point, temp, expr_ty));
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block.unit()
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}
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}
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@ -805,27 +805,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
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target
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}
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/// Utility function for *non*-scope code to build their own drops
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pub fn build_drop(&mut self,
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block: BasicBlock,
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span: Span,
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location: Place<'tcx>,
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ty: Ty<'tcx>) -> BlockAnd<()> {
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if !self.hir.needs_drop(ty) {
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return block.unit();
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}
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let source_info = self.source_info(span);
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let next_target = self.cfg.start_new_block();
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let diverge_target = self.diverge_cleanup();
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self.cfg.terminate(block, source_info,
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TerminatorKind::Drop {
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location,
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target: next_target,
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unwind: Some(diverge_target),
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});
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next_target.unit()
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}
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/// Utility function for *non*-scope code to build their own drops
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pub fn build_drop_and_replace(&mut self,
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block: BasicBlock,
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@ -49,7 +49,6 @@ fn mirror_stmts<'a, 'tcx>(
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for (index, stmt) in stmts.iter().enumerate() {
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let hir_id = stmt.hir_id;
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let opt_dxn_ext = cx.region_scope_tree.opt_destruction_scope(hir_id.local_id);
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let stmt_span = StatementSpan(cx.tcx.hir().span(hir_id));
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match stmt.node {
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hir::StmtKind::Expr(ref expr) |
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hir::StmtKind::Semi(ref expr) => {
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@ -62,7 +61,6 @@ fn mirror_stmts<'a, 'tcx>(
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expr: expr.to_ref(),
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},
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opt_destruction_scope: opt_dxn_ext,
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span: stmt_span,
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})))
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}
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hir::StmtKind::Item(..) => {
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@ -107,7 +105,6 @@ fn mirror_stmts<'a, 'tcx>(
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lint_level: LintLevel::Explicit(local.hir_id),
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},
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opt_destruction_scope: opt_dxn_ext,
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span: stmt_span,
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})));
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}
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}
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@ -55,14 +55,10 @@ pub enum StmtRef<'tcx> {
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Mirror(Box<Stmt<'tcx>>),
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}
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#[derive(Clone, Debug)]
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pub struct StatementSpan(pub Span);
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#[derive(Clone, Debug)]
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pub struct Stmt<'tcx> {
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pub kind: StmtKind<'tcx>,
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pub opt_destruction_scope: Option<region::Scope>,
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pub span: StatementSpan,
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}
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#[derive(Clone, Debug)]
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@ -24,7 +24,7 @@ impl Drop for S {
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// let mut _0: ();
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// let _1: std::boxed::Box<S>;
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// let mut _2: std::boxed::Box<S>;
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// let mut _3: ();
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// let _3: ();
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// let mut _4: std::boxed::Box<S>;
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// scope 1 {
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// }
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@ -50,6 +50,7 @@ impl Drop for S {
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//
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// bb4: {
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// StorageDead(_2);
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// StorageLive(_3);
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// StorageLive(_4);
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// _4 = move _1;
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// _3 = const std::mem::drop::<std::boxed::Box<S>>(move _4) -> [return: bb5, unwind: bb7];
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@ -69,6 +70,7 @@ impl Drop for S {
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//
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// bb8: {
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// StorageDead(_4);
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// StorageDead(_3);
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// _0 = ();
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// drop(_1) -> bb9;
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// }
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@ -61,12 +61,14 @@ fn main() {
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// END rustc.foo.CopyPropagation.after.mir
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// START rustc.bar.CopyPropagation.before.mir
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// bb0: {
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// StorageLive(_2);
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// StorageLive(_3);
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// _3 = _1;
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// _2 = const dummy(move _3) -> bb1;
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// }
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// bb1: {
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// StorageDead(_3);
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// StorageDead(_2);
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// _1 = const 5u8;
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// ...
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// return;
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// }
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// bb1: {
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// StorageDead(_3);
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// StorageDead(_2);
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// goto -> bb5;
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// }
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// bb2: {
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@ -36,6 +37,7 @@ fn main() {
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// goto -> bb3;
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// }
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// bb7: {
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// StorageLive(_2);
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// StorageLive(_3);
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// goto -> bb1;
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// }
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@ -54,6 +54,7 @@ fn main() {
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// }
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// bb2: {
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// ...
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// StorageLive(_6);
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// StorageLive(_7);
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// _7 = move _2;
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// _6 = const take::<Foo>(move _7) -> [return: bb9, unwind: bb8];
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@ -81,16 +82,20 @@ fn main() {
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// }
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// bb8 (cleanup): {
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// StorageDead(_7);
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// StorageDead(_6);
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// goto -> bb7;
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// }
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// bb9: {
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// StorageDead(_7);
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// StorageDead(_6);
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// StorageLive(_8);
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// StorageLive(_9);
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// _9 = move _3;
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// _8 = const take::<Bar>(move _9) -> [return: bb10, unwind: bb11];
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// }
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// bb10: {
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// StorageDead(_9);
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// StorageDead(_8);
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// ...
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// StorageDead(_3);
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// StorageDead(_2);
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@ -98,6 +103,7 @@ fn main() {
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// }
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// bb11 (cleanup): {
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// StorageDead(_9);
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// StorageDead(_8);
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// goto -> bb7;
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// }
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// bb12: {
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@ -25,6 +25,7 @@ fn main() {
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// falseUnwind -> [real: bb3, cleanup: bb1];
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// }
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// bb3: {
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// StorageLive(_3);
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// StorageLive(_4);
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// _4 = _1;
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// FakeRead(ForMatchedPlace, _4);
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@ -34,6 +35,7 @@ fn main() {
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// bb5: {
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// _3 = ();
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// StorageDead(_4);
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// StorageDead(_3);
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// _1 = const true;
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// _2 = ();
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// goto -> bb2;
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@ -41,6 +43,7 @@ fn main() {
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// bb6: {
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// _0 = ();
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// StorageDead(_4);
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// StorageDead(_3);
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// StorageDead(_1);
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// return;
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// }
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@ -42,7 +42,7 @@ impl S {
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// START rustc.test.ElaborateDrops.after.mir
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// let mut _0: ();
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// let _1: S;
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// let mut _3: ();
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// let _3: ();
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// let mut _4: S;
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// let mut _5: S;
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// let mut _6: bool;
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@ -21,7 +21,7 @@ fn main() {
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// let _2: i32;
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// let mut _3: bool;
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// let mut _4: !;
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// let mut _5: ();
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// let _5: ();
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// let mut _6: &i32;
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// scope 1 {
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// }
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@ -73,12 +73,14 @@ fn main() {
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// bb12: {
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// FakeRead(ForLet, _2);
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// StorageDead(_3);
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// StorageLive(_5);
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// StorageLive(_6);
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// _6 = &_2;
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// _5 = const std::mem::drop::<&i32>(move _6) -> [return: bb13, unwind: bb4];
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// }
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// bb13: {
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// StorageDead(_6);
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// StorageDead(_5);
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// _1 = ();
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// StorageDead(_2);
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// goto -> bb1;
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@ -25,6 +25,7 @@ fn main() {
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// bb3: { // Entry into the loop
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// _1 = ();
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// StorageDead(_2);
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// StorageDead(_1);
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// goto -> bb5;
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// }
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// ...
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@ -75,6 +75,7 @@ fn main() {
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// goto -> bb14;
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// }
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// bb14: {
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// StorageDead(_3);
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// _0 = ();
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// StorageDead(_2);
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// StorageDead(_1);
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@ -22,9 +22,9 @@ fn main() {
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// END RUST SOURCE
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// START rustc.main.nll.0.mir
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// | '_#2r | U0 | {bb2[0..=8], bb3[0], bb5[0..=1]}
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// | '_#3r | U0 | {bb2[1..=8], bb3[0], bb5[0..=1]}
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// | '_#4r | U0 | {bb2[4..=8], bb3[0], bb5[0..=1]}
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// | '_#2r | U0 | {bb2[0..=8], bb3[0], bb5[0..=2]}
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// | '_#3r | U0 | {bb2[1..=8], bb3[0], bb5[0..=2]}
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// | '_#4r | U0 | {bb2[4..=8], bb3[0], bb5[0..=2]}
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// END rustc.main.nll.0.mir
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// START rustc.main.nll.0.mir
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// let _2: &'_#3r usize;
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@ -12,6 +12,7 @@ fn main() {
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// StorageLive(_1);
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// _1 = const 0i32;
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// FakeRead(ForLet, _1);
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// StorageLive(_2);
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// StorageLive(_3);
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// StorageLive(_4);
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// StorageLive(_5);
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@ -23,6 +24,7 @@ fn main() {
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// _2 = ();
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// StorageDead(_4);
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// StorageDead(_3);
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// StorageDead(_2);
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// StorageLive(_6);
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// _6 = const 1i32;
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// FakeRead(ForLet, _6);
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32
src/test/ui/generator/issue-61442-stmt-expr-with-drop.rs
Normal file
32
src/test/ui/generator/issue-61442-stmt-expr-with-drop.rs
Normal file
@ -0,0 +1,32 @@
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// Test that we don't consider temporaries for statement expressions as live
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// across yields
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// check-pass
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// edition:2018
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#![feature(async_await, generators, generator_trait)]
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use std::ops::Generator;
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async fn drop_and_await() {
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async {};
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async {}.await;
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}
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fn drop_and_yield() {
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let x = || {
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String::new();
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yield;
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};
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Box::pin(x).as_mut().resume();
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let y = static || {
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String::new();
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yield;
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};
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Box::pin(y).as_mut().resume();
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}
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fn main() {
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drop_and_await();
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drop_and_yield();
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}
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