diff options
| -rw-r--r-- | clippy_lints/src/needless_return.rs | 45 |
1 files changed, 43 insertions, 2 deletions
diff --git a/clippy_lints/src/needless_return.rs b/clippy_lints/src/needless_return.rs index a8876619ac1..861a7ec558c 100644 --- a/clippy_lints/src/needless_return.rs +++ b/clippy_lints/src/needless_return.rs @@ -2,12 +2,14 @@ use rustc_lint::{LateLintPass, LateContext}; use rustc_ast::ast::Attribute; use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_errors::Applicability; -use rustc_hir::intravisit::FnKind; +use rustc_hir::intravisit::{FnKind, walk_expr, NestedVisitorMap, Visitor}; use rustc_span::source_map::Span; use rustc_middle::lint::in_external_macro; +use rustc_middle::hir::map::Map; +use rustc_middle::ty::subst::GenericArgKind; use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, HirId, MatchSource, StmtKind}; -use crate::utils::{snippet_opt, span_lint_and_sugg, span_lint_and_then}; +use crate::utils::{fn_def_id, snippet_opt, span_lint_and_sugg, span_lint_and_then}; declare_clippy_lint! { /// **What it does:** Checks for return statements at the end of a block. @@ -164,3 +166,42 @@ fn emit_return_lint(cx: &LateContext<'_>, ret_span: Span, inner_span: Option<Spa }, } } + +fn last_statement_borrows<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool { + let mut visitor = BorrowVisitor { cx, borrows: false }; + walk_expr(&mut visitor, expr); + visitor.borrows +} + +struct BorrowVisitor<'a, 'tcx> { + cx: &'a LateContext<'tcx>, + borrows: bool, +} + +impl<'tcx> Visitor<'tcx> for BorrowVisitor<'_, 'tcx> { + type Map = Map<'tcx>; + + fn visit_expr(&mut self, expr: &'tcx Expr<'_>) { + if self.borrows { + return; + } + + if let Some(def_id) = fn_def_id(self.cx, expr) { + self.borrows = self + .cx + .tcx + .fn_sig(def_id) + .output() + .skip_binder() + .walk() + .any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_))); + } + + walk_expr(self, expr); + } + + fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { + NestedVisitorMap::None + } +} + |