| use crate::map_unit_fn::OPTION_MAP_UNIT_FN; |
| use crate::matches::MATCH_AS_REF; |
| use clippy_utils::source::{snippet_with_applicability, snippet_with_context}; |
| use clippy_utils::sugg::Sugg; |
| use clippy_utils::ty::{is_copy, is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function}; |
| use clippy_utils::{ |
| can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local_id, |
| peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, CaptureKind, |
| }; |
| use rustc_ast::util::parser::PREC_POSTFIX; |
| use rustc_errors::Applicability; |
| use rustc_hir::def::Res; |
| use rustc_hir::LangItem::{OptionNone, OptionSome}; |
| use rustc_hir::{BindingAnnotation, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path, QPath}; |
| use rustc_lint::LateContext; |
| use rustc_span::{sym, SyntaxContext}; |
| |
| #[expect(clippy::too_many_arguments)] |
| #[expect(clippy::too_many_lines)] |
| pub(super) fn check_with<'tcx, F>( |
| cx: &LateContext<'tcx>, |
| expr: &'tcx Expr<'_>, |
| scrutinee: &'tcx Expr<'_>, |
| then_pat: &'tcx Pat<'_>, |
| then_body: &'tcx Expr<'_>, |
| else_pat: Option<&'tcx Pat<'_>>, |
| else_body: &'tcx Expr<'_>, |
| get_some_expr_fn: F, |
| ) -> Option<SuggInfo<'tcx>> |
| where |
| F: Fn(&LateContext<'tcx>, &'tcx Pat<'_>, &'tcx Expr<'_>, SyntaxContext) -> Option<SomeExpr<'tcx>>, |
| { |
| let (scrutinee_ty, ty_ref_count, ty_mutability) = |
| peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrutinee)); |
| if !(is_type_diagnostic_item(cx, scrutinee_ty, sym::Option) |
| && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::Option)) |
| { |
| return None; |
| } |
| |
| let expr_ctxt = expr.span.ctxt(); |
| let (some_expr, some_pat, pat_ref_count, is_wild_none) = match ( |
| try_parse_pattern(cx, then_pat, expr_ctxt), |
| else_pat.map_or(Some(OptionPat::Wild), |p| try_parse_pattern(cx, p, expr_ctxt)), |
| ) { |
| (Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => { |
| (else_body, pattern, ref_count, true) |
| }, |
| (Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => { |
| (else_body, pattern, ref_count, false) |
| }, |
| (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild)) if is_none_expr(cx, else_body) => { |
| (then_body, pattern, ref_count, true) |
| }, |
| (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None)) if is_none_expr(cx, else_body) => { |
| (then_body, pattern, ref_count, false) |
| }, |
| _ => return None, |
| }; |
| |
| // Top level or patterns aren't allowed in closures. |
| if matches!(some_pat.kind, PatKind::Or(_)) { |
| return None; |
| } |
| |
| let Some(some_expr) = get_some_expr_fn(cx, some_pat, some_expr, expr_ctxt) else { |
| return None; |
| }; |
| |
| // These two lints will go back and forth with each other. |
| if cx.typeck_results().expr_ty(some_expr.expr) == cx.tcx.types.unit |
| && !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id) |
| { |
| return None; |
| } |
| |
| // `map` won't perform any adjustments. |
| if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() { |
| return None; |
| } |
| |
| // Determine which binding mode to use. |
| let explicit_ref = some_pat.contains_explicit_ref_binding(); |
| let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then_some(ty_mutability)); |
| |
| let as_ref_str = match binding_ref { |
| Some(Mutability::Mut) => ".as_mut()", |
| Some(Mutability::Not) => ".as_ref()", |
| None => "", |
| }; |
| |
| match can_move_expr_to_closure(cx, some_expr.expr) { |
| Some(captures) => { |
| // Check if captures the closure will need conflict with borrows made in the scrutinee. |
| // TODO: check all the references made in the scrutinee expression. This will require interacting |
| // with the borrow checker. Currently only `<local>[.<field>]*` is checked for. |
| if let Some(binding_ref_mutability) = binding_ref { |
| let e = peel_hir_expr_while(scrutinee, |e| match e.kind { |
| ExprKind::Field(e, _) | ExprKind::AddrOf(_, _, e) => Some(e), |
| _ => None, |
| }); |
| if let ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(l), .. })) = e.kind { |
| match captures.get(l) { |
| Some(CaptureKind::Value | CaptureKind::Ref(Mutability::Mut)) => return None, |
| Some(CaptureKind::Ref(Mutability::Not)) if binding_ref_mutability == Mutability::Mut => { |
| return None; |
| }, |
| Some(CaptureKind::Ref(Mutability::Not)) | None => (), |
| } |
| } |
| } |
| }, |
| None => return None, |
| }; |
| |
| let mut app = Applicability::MachineApplicable; |
| |
| // Remove address-of expressions from the scrutinee. Either `as_ref` will be called, or |
| // it's being passed by value. |
| let scrutinee = peel_hir_expr_refs(scrutinee).0; |
| let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app); |
| let scrutinee_str = if scrutinee.span.eq_ctxt(expr.span) && scrutinee.precedence().order() < PREC_POSTFIX { |
| format!("({scrutinee_str})") |
| } else { |
| scrutinee_str.into() |
| }; |
| |
| let closure_expr_snip = some_expr.to_snippet_with_context(cx, expr_ctxt, &mut app); |
| let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind { |
| if_chain! { |
| if !some_expr.needs_unsafe_block; |
| if let Some(func) = can_pass_as_func(cx, id, some_expr.expr); |
| if func.span.eq_ctxt(some_expr.expr.span); |
| then { |
| snippet_with_applicability(cx, func.span, "..", &mut app).into_owned() |
| } else { |
| if path_to_local_id(some_expr.expr, id) |
| && !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id) |
| && binding_ref.is_some() |
| { |
| return None; |
| } |
| |
| // `ref` and `ref mut` annotations were handled earlier. |
| let annotation = if matches!(annotation, BindingAnnotation::MUT) { |
| "mut " |
| } else { |
| "" |
| }; |
| |
| if some_expr.needs_unsafe_block { |
| format!("|{annotation}{some_binding}| unsafe {{ {closure_expr_snip} }}") |
| } else { |
| format!("|{annotation}{some_binding}| {closure_expr_snip}") |
| } |
| } |
| } |
| } else if !is_wild_none && explicit_ref.is_none() { |
| // TODO: handle explicit reference annotations. |
| let pat_snip = snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0; |
| if some_expr.needs_unsafe_block { |
| format!("|{pat_snip}| unsafe {{ {closure_expr_snip} }}") |
| } else { |
| format!("|{pat_snip}| {closure_expr_snip}") |
| } |
| } else { |
| // Refutable bindings and mixed reference annotations can't be handled by `map`. |
| return None; |
| }; |
| |
| // relies on the fact that Option<T>: Copy where T: copy |
| let scrutinee_impl_copy = is_copy(cx, scrutinee_ty); |
| |
| Some(SuggInfo { |
| needs_brackets: else_pat.is_none() && is_else_clause(cx.tcx, expr), |
| scrutinee_impl_copy, |
| scrutinee_str, |
| as_ref_str, |
| body_str, |
| app, |
| }) |
| } |
| |
| pub struct SuggInfo<'a> { |
| pub needs_brackets: bool, |
| pub scrutinee_impl_copy: bool, |
| pub scrutinee_str: String, |
| pub as_ref_str: &'a str, |
| pub body_str: String, |
| pub app: Applicability, |
| } |
| |
| // Checks whether the expression could be passed as a function, or whether a closure is needed. |
| // Returns the function to be passed to `map` if it exists. |
| fn can_pass_as_func<'tcx>(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> { |
| match expr.kind { |
| ExprKind::Call(func, [arg]) |
| if path_to_local_id(arg, binding) |
| && cx.typeck_results().expr_adjustments(arg).is_empty() |
| && !type_is_unsafe_function(cx, cx.typeck_results().expr_ty(func).peel_refs()) => |
| { |
| Some(func) |
| }, |
| _ => None, |
| } |
| } |
| |
| #[derive(Debug)] |
| pub(super) enum OptionPat<'a> { |
| Wild, |
| None, |
| Some { |
| // The pattern contained in the `Some` tuple. |
| pattern: &'a Pat<'a>, |
| // The number of references before the `Some` tuple. |
| // e.g. `&&Some(_)` has a ref count of 2. |
| ref_count: usize, |
| }, |
| } |
| |
| pub(super) struct SomeExpr<'tcx> { |
| pub expr: &'tcx Expr<'tcx>, |
| pub needs_unsafe_block: bool, |
| pub needs_negated: bool, // for `manual_filter` lint |
| } |
| |
| impl<'tcx> SomeExpr<'tcx> { |
| pub fn new_no_negated(expr: &'tcx Expr<'tcx>, needs_unsafe_block: bool) -> Self { |
| Self { |
| expr, |
| needs_unsafe_block, |
| needs_negated: false, |
| } |
| } |
| |
| pub fn to_snippet_with_context( |
| &self, |
| cx: &LateContext<'tcx>, |
| ctxt: SyntaxContext, |
| app: &mut Applicability, |
| ) -> Sugg<'tcx> { |
| let sugg = Sugg::hir_with_context(cx, self.expr, ctxt, "..", app); |
| if self.needs_negated { !sugg } else { sugg } |
| } |
| } |
| |
| // Try to parse into a recognized `Option` pattern. |
| // i.e. `_`, `None`, `Some(..)`, or a reference to any of those. |
| pub(super) fn try_parse_pattern<'tcx>( |
| cx: &LateContext<'tcx>, |
| pat: &'tcx Pat<'_>, |
| ctxt: SyntaxContext, |
| ) -> Option<OptionPat<'tcx>> { |
| fn f<'tcx>( |
| cx: &LateContext<'tcx>, |
| pat: &'tcx Pat<'_>, |
| ref_count: usize, |
| ctxt: SyntaxContext, |
| ) -> Option<OptionPat<'tcx>> { |
| match pat.kind { |
| PatKind::Wild => Some(OptionPat::Wild), |
| PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1, ctxt), |
| PatKind::Path(ref qpath) if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionNone) => { |
| Some(OptionPat::None) |
| }, |
| PatKind::TupleStruct(ref qpath, [pattern], _) |
| if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionSome) && pat.span.ctxt() == ctxt => |
| { |
| Some(OptionPat::Some { pattern, ref_count }) |
| }, |
| _ => None, |
| } |
| } |
| f(cx, pat, 0, ctxt) |
| } |
| |
| // Checks for the `None` value. |
| fn is_none_expr(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { |
| is_res_lang_ctor(cx, path_res(cx, peel_blocks(expr)), OptionNone) |
| } |