diff --git a/clippy_lints/src/format_impl.rs b/clippy_lints/src/format_impl.rs index 9360eb1fa91a..93517076cda0 100644 --- a/clippy_lints/src/format_impl.rs +++ b/clippy_lints/src/format_impl.rs @@ -7,7 +7,7 @@ use rustc_hir::{Expr, ExprKind, Impl, ImplItem, ImplItemKind, QPath}; use rustc_lint::{LateContext, LateLintPass}; use rustc_session::impl_lint_pass; use rustc_span::symbol::kw; -use rustc_span::{sym, Span, Symbol}; +use rustc_span::{sym, Symbol}; declare_clippy_lint! { /// ### What it does @@ -119,123 +119,132 @@ impl<'tcx> LateLintPass<'tcx> for FormatImpl { } fn check_impl_item_post(&mut self, cx: &LateContext<'_>, impl_item: &ImplItem<'_>) { - // Assume no nested Impl of Debug and Display within eachother + // Assume no nested Impl of Debug and Display within each other if is_format_trait_impl(cx, impl_item).is_some() { self.format_trait_impl = None; } } fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { - let Some(format_trait_impl) = self.format_trait_impl else { - return; - }; - - if format_trait_impl.name == sym::Display { - check_to_string_in_display(cx, expr); + if let Some(format_trait_impl) = self.format_trait_impl { + let linter = FormatImplExpr { + cx, + expr, + format_trait_impl, + }; + linter.check_to_string_in_display(); + linter.check_self_in_format_args(); + linter.check_print_in_format_impl(); } - - check_self_in_format_args(cx, expr, format_trait_impl); - check_print_in_format_impl(cx, expr, format_trait_impl); } } -fn check_to_string_in_display(cx: &LateContext<'_>, expr: &Expr<'_>) { - if let ExprKind::MethodCall(path, self_arg, ..) = expr.kind - // Get the hir_id of the object we are calling the method on - // Is the method to_string() ? - && path.ident.name == sym::to_string - // Is the method a part of the ToString trait? (i.e. not to_string() implemented - // separately) - && let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) - && is_diag_trait_item(cx, expr_def_id, sym::ToString) - // Is the method is called on self - && let ExprKind::Path(QPath::Resolved(_, path)) = self_arg.kind - && let [segment] = path.segments - && segment.ident.name == kw::SelfLower - { - span_lint( - cx, - RECURSIVE_FORMAT_IMPL, - expr.span, - "using `self.to_string` in `fmt::Display` implementation will cause infinite recursion", - ); - } +struct FormatImplExpr<'a, 'tcx> { + cx: &'a LateContext<'tcx>, + expr: &'tcx Expr<'tcx>, + format_trait_impl: FormatTraitNames, } -fn check_self_in_format_args<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, impl_trait: FormatTraitNames) { - // Check each arg in format calls - do we ever use Display on self (directly or via deref)? - if let Some(outer_macro) = root_macro_call_first_node(cx, expr) - && let macro_def_id = outer_macro.def_id - && is_format_macro(cx, macro_def_id) - && let Some(format_args) = find_format_args(cx, expr, outer_macro.expn) - { - for piece in &format_args.template { - if let FormatArgsPiece::Placeholder(placeholder) = piece - && let trait_name = match placeholder.format_trait { - FormatTrait::Display => sym::Display, - FormatTrait::Debug => sym::Debug, - FormatTrait::LowerExp => sym!(LowerExp), - FormatTrait::UpperExp => sym!(UpperExp), - FormatTrait::Octal => sym!(Octal), - FormatTrait::Pointer => sym::Pointer, - FormatTrait::Binary => sym!(Binary), - FormatTrait::LowerHex => sym!(LowerHex), - FormatTrait::UpperHex => sym!(UpperHex), +impl<'a, 'tcx> FormatImplExpr<'a, 'tcx> { + fn check_to_string_in_display(&self) { + if self.format_trait_impl.name == sym::Display + && let ExprKind::MethodCall(path, self_arg, ..) = self.expr.kind + // Get the hir_id of the object we are calling the method on + // Is the method to_string() ? + && path.ident.name == sym::to_string + // Is the method a part of the ToString trait? (i.e. not to_string() implemented + // separately) + && let Some(expr_def_id) = self.cx.typeck_results().type_dependent_def_id(self.expr.hir_id) + && is_diag_trait_item(self.cx, expr_def_id, sym::ToString) + // Is the method is called on self + && let ExprKind::Path(QPath::Resolved(_, path)) = self_arg.kind + && let [segment] = path.segments + && segment.ident.name == kw::SelfLower + { + span_lint( + self.cx, + RECURSIVE_FORMAT_IMPL, + self.expr.span, + "using `self.to_string` in `fmt::Display` implementation will cause infinite recursion", + ); + } + } + + fn check_self_in_format_args(&self) { + // Check each arg in format calls - do we ever use Display on self (directly or via deref)? + if let Some(outer_macro) = root_macro_call_first_node(self.cx, self.expr) + && let macro_def_id = outer_macro.def_id + && is_format_macro(self.cx, macro_def_id) + && let Some(format_args) = find_format_args(self.cx, self.expr, outer_macro.expn) + { + for piece in &format_args.template { + if let FormatArgsPiece::Placeholder(placeholder) = piece + && let trait_name = match placeholder.format_trait { + FormatTrait::Display => sym::Display, + FormatTrait::Debug => sym::Debug, + FormatTrait::LowerExp => sym!(LowerExp), + FormatTrait::UpperExp => sym!(UpperExp), + FormatTrait::Octal => sym!(Octal), + FormatTrait::Pointer => sym::Pointer, + FormatTrait::Binary => sym!(Binary), + FormatTrait::LowerHex => sym!(LowerHex), + FormatTrait::UpperHex => sym!(UpperHex), + } + && trait_name == self.format_trait_impl.name + && let Ok(index) = placeholder.argument.index + && let Some(arg) = format_args.arguments.all_args().get(index) + && let Ok(arg_expr) = find_format_arg_expr(self.expr, arg) + { + self.check_format_arg_self(arg_expr); } - && trait_name == impl_trait.name - && let Ok(index) = placeholder.argument.index - && let Some(arg) = format_args.arguments.all_args().get(index) - && let Ok(arg_expr) = find_format_arg_expr(expr, arg) - { - check_format_arg_self(cx, expr.span, arg_expr, impl_trait); } } } -} -fn check_format_arg_self(cx: &LateContext<'_>, span: Span, arg: &Expr<'_>, impl_trait: FormatTraitNames) { - // Handle multiple dereferencing of references e.g. &&self - // Handle dereference of &self -> self that is equivalent (i.e. via *self in fmt() impl) - // Since the argument to fmt is itself a reference: &self - let reference = peel_ref_operators(cx, arg); - let map = cx.tcx.hir(); - // Is the reference self? - if path_to_local(reference).map(|x| map.name(x)) == Some(kw::SelfLower) { - let FormatTraitNames { name, .. } = impl_trait; - span_lint( - cx, - RECURSIVE_FORMAT_IMPL, - span, - &format!("using `self` as `{name}` in `impl {name}` will cause infinite recursion"), - ); + fn check_format_arg_self(&self, arg: &Expr<'_>) { + // Handle multiple dereferencing of references e.g. &&self + // Handle dereference of &self -> self that is equivalent (i.e. via *self in fmt() impl) + // Since the argument to fmt is itself a reference: &self + let reference = peel_ref_operators(self.cx, arg); + let map = self.cx.tcx.hir(); + // Is the reference self? + if path_to_local(reference).map(|x| map.name(x)) == Some(kw::SelfLower) { + let FormatTraitNames { name, .. } = self.format_trait_impl; + span_lint( + self.cx, + RECURSIVE_FORMAT_IMPL, + self.expr.span, + &format!("using `self` as `{name}` in `impl {name}` will cause infinite recursion"), + ); + } } -} -fn check_print_in_format_impl(cx: &LateContext<'_>, expr: &Expr<'_>, impl_trait: FormatTraitNames) { - if let Some(macro_call) = root_macro_call_first_node(cx, expr) - && let Some(name) = cx.tcx.get_diagnostic_name(macro_call.def_id) - { - let replacement = match name { - sym::print_macro | sym::eprint_macro => "write", - sym::println_macro | sym::eprintln_macro => "writeln", - _ => return, - }; + fn check_print_in_format_impl(&self) { + if let Some(macro_call) = root_macro_call_first_node(self.cx, self.expr) + && let Some(name) = self.cx.tcx.get_diagnostic_name(macro_call.def_id) + { + let replacement = match name { + sym::print_macro | sym::eprint_macro => "write", + sym::println_macro | sym::eprintln_macro => "writeln", + _ => return, + }; - let name = name.as_str().strip_suffix("_macro").unwrap(); + let name = name.as_str().strip_suffix("_macro").unwrap(); - span_lint_and_sugg( - cx, - PRINT_IN_FORMAT_IMPL, - macro_call.span, - &format!("use of `{name}!` in `{}` impl", impl_trait.name), - "replace with", - if let Some(formatter_name) = impl_trait.formatter_name { - format!("{replacement}!({formatter_name}, ..)") - } else { - format!("{replacement}!(..)") - }, - Applicability::HasPlaceholders, - ); + span_lint_and_sugg( + self.cx, + PRINT_IN_FORMAT_IMPL, + macro_call.span, + &format!("use of `{name}!` in `{}` impl", self.format_trait_impl.name), + "replace with", + if let Some(formatter_name) = self.format_trait_impl.formatter_name { + format!("{replacement}!({formatter_name}, ..)") + } else { + format!("{replacement}!(..)") + }, + Applicability::HasPlaceholders, + ); + } } }