New upstream version 1.71.1+dfsg1

[rustc.git] / compiler / rustc_lint / src / unused.rs

diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 28cc63198af55628a97077bb1dd2986650336e0a..8f75fa11dd9a2e70cf73f7b174b591994f577f95 100644 (file)
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -256,7 +256,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 }
                 ty::Adt(def, _) => is_def_must_use(cx, def.did(), span),
                 ty::Alias(ty::Opaque, ty::AliasTy { def_id: def, .. }) => {
-                    elaborate(cx.tcx, cx.tcx.explicit_item_bounds(def).iter().cloned())
+                    elaborate(cx.tcx, cx.tcx.explicit_item_bounds(def).subst_identity_iter_copied())
                         // We only care about self bounds for the impl-trait
                         .filter_only_self()
                         .find_map(|(pred, _span)| {
@@ -571,36 +571,50 @@ trait UnusedDelimLint {
             }
         }
 
-        // Prevent false-positives in cases like `fn x() -> u8 { ({ 0 } + 1) }`
-        let lhs_needs_parens = {
+        // Check if LHS needs parens to prevent false-positives in cases like `fn x() -> u8 { ({ 0 } + 1) }`.
+        {
             let mut innermost = inner;
             loop {
                 innermost = match &innermost.kind {
-                    ExprKind::Binary(_, lhs, _rhs) => lhs,
+                    ExprKind::Binary(_op, lhs, _rhs) => lhs,
                     ExprKind::Call(fn_, _params) => fn_,
                     ExprKind::Cast(expr, _ty) => expr,
                     ExprKind::Type(expr, _ty) => expr,
                     ExprKind::Index(base, _subscript) => base,
-                    _ => break false,
+                    _ => break,
                 };
                 if !classify::expr_requires_semi_to_be_stmt(innermost) {
-                    break true;
+                    return true;
                 }
             }
-        };
+        }
 
-        lhs_needs_parens
-            || (followed_by_block
-                && match &inner.kind {
-                    ExprKind::Ret(_)
-                    | ExprKind::Break(..)
-                    | ExprKind::Yield(..)
-                    | ExprKind::Yeet(..) => true,
-                    ExprKind::Range(_lhs, Some(rhs), _limits) => {
-                        matches!(rhs.kind, ExprKind::Block(..))
-                    }
-                    _ => parser::contains_exterior_struct_lit(&inner),
-                })
+        // Check if RHS needs parens to prevent false-positives in cases like `if (() == return) {}`.
+        if !followed_by_block {
+            return false;
+        }
+        let mut innermost = inner;
+        loop {
+            innermost = match &innermost.kind {
+                ExprKind::Unary(_op, expr) => expr,
+                ExprKind::Binary(_op, _lhs, rhs) => rhs,
+                ExprKind::AssignOp(_op, _lhs, rhs) => rhs,
+                ExprKind::Assign(_lhs, rhs, _span) => rhs,
+
+                ExprKind::Ret(_) | ExprKind::Yield(..) | ExprKind::Yeet(..) => return true,
+
+                ExprKind::Break(_label, None) => return false,
+                ExprKind::Break(_label, Some(break_expr)) => {
+                    return matches!(break_expr.kind, ExprKind::Block(..));
+                }
+
+                ExprKind::Range(_lhs, Some(rhs), _limits) => {
+                    return matches!(rhs.kind, ExprKind::Block(..));
+                }
+
+                _ => return parser::contains_exterior_struct_lit(&inner),
+            }
+        }
     }
 
     fn emit_unused_delims_expr(
@@ -638,26 +652,20 @@ trait UnusedDelimLint {
             return;
         }
         let spans = match value.kind {
-            ast::ExprKind::Block(ref block, None) if block.stmts.len() == 1 => {
-                if let Some(span) = block.stmts[0].span.find_ancestor_inside(value.span) {
-                    Some((value.span.with_hi(span.lo()), value.span.with_lo(span.hi())))
-                } else {
-                    None
-                }
-            }
+            ast::ExprKind::Block(ref block, None) if block.stmts.len() == 1 => block.stmts[0]
+                .span
+                .find_ancestor_inside(value.span)
+                .map(|span| (value.span.with_hi(span.lo()), value.span.with_lo(span.hi()))),
             ast::ExprKind::Paren(ref expr) => {
-                let expr_span = expr.span.find_ancestor_inside(value.span);
-                if let Some(expr_span) = expr_span {
-                    Some((value.span.with_hi(expr_span.lo()), value.span.with_lo(expr_span.hi())))
-                } else {
-                    None
-                }
+                expr.span.find_ancestor_inside(value.span).map(|expr_span| {
+                    (value.span.with_hi(expr_span.lo()), value.span.with_lo(expr_span.hi()))
+                })
             }
             _ => return,
         };
         let keep_space = (
-            left_pos.map_or(false, |s| s >= value.span.lo()),
-            right_pos.map_or(false, |s| s <= value.span.hi()),
+            left_pos.is_some_and(|s| s >= value.span.lo()),
+            right_pos.is_some_and(|s| s <= value.span.hi()),
         );
         self.emit_unused_delims(cx, value.span, spans, ctx.into(), keep_space);
     }
@@ -930,11 +938,10 @@ impl UnusedParens {
                 // Otherwise proceed with linting.
                 _ => {}
             }
-            let spans = if let Some(inner) = inner.span.find_ancestor_inside(value.span) {
-                Some((value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())))
-            } else {
-                None
-            };
+            let spans = inner
+                .span
+                .find_ancestor_inside(value.span)
+                .map(|inner| (value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())));
             self.emit_unused_delims(cx, value.span, spans, "pattern", keep_space);
         }
     }
@@ -1045,11 +1052,11 @@ impl EarlyLintPass for UnusedParens {
                         if self.with_self_ty_parens && b.generic_params.len() > 0 => {}
                     ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
                     _ => {
-                        let spans = if let Some(r) = r.span.find_ancestor_inside(ty.span) {
-                            Some((ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())))
-                        } else {
-                            None
-                        };
+                        let spans = r
+                            .span
+                            .find_ancestor_inside(ty.span)
+                            .map(|r| (ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())));
+
                         self.emit_unused_delims(cx, ty.span, spans, "type", (false, false));
                     }
                 }