use crate::{map_unit_fn::OPTION_MAP_UNIT_FN, matches::MATCH_AS_REF};
use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher::IfLetOrMatch;
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
-use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable};
+use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function};
use clippy_utils::{
- can_move_expr_to_closure, in_constant, is_allowed, is_else_clause, is_lang_ctor, match_var, peel_hir_expr_refs,
+ can_move_expr_to_closure, in_constant, is_else_clause, is_lang_ctor, is_lint_allowed, 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::LangItem::{OptionNone, OptionSome};
-use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, MatchSource, Mutability, Pat, PatKind};
+use rustc_hir::{
+ def::Res, Arm, BindingAnnotation, Block, BlockCheckMode, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path,
+ QPath, UnsafeSource,
+};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::{
- symbol::{sym, Ident},
- SyntaxContext,
-};
+use rustc_span::{sym, SyntaxContext};
declare_clippy_lint! {
- /// **What it does:** Checks for usages of `match` which could be implemented using `map`
- ///
- /// **Why is this bad?** Using the `map` method is clearer and more concise.
- ///
- /// **Known problems:** None.
+ /// ### What it does
+ /// Checks for usages of `match` which could be implemented using `map`
///
- /// **Example:**
+ /// ### Why is this bad?
+ /// Using the `map` method is clearer and more concise.
///
+ /// ### Example
/// ```rust
/// match Some(0) {
/// Some(x) => Some(x + 1),
/// ```rust
/// Some(0).map(|x| x + 1);
/// ```
+ #[clippy::version = "1.52.0"]
pub MANUAL_MAP,
style,
"reimplementation of `map`"
impl LateLintPass<'_> for ManualMap {
#[allow(clippy::too_many_lines)]
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if let ExprKind::Match(
- scrutinee,
- [arm1 @ Arm { guard: None, .. }, arm2 @ Arm { guard: None, .. }],
- match_kind,
- ) = expr.kind
+ let (scrutinee, then_pat, then_body, else_pat, else_body) = match IfLetOrMatch::parse(cx, expr) {
+ Some(IfLetOrMatch::IfLet(scrutinee, pat, body, Some(r#else))) => (scrutinee, pat, body, None, r#else),
+ Some(IfLetOrMatch::Match(
+ scrutinee,
+ [arm1 @ Arm { guard: None, .. }, arm2 @ Arm { guard: None, .. }],
+ _,
+ )) => (scrutinee, arm1.pat, arm1.body, Some(arm2.pat), arm2.body),
+ _ => return,
+ };
+ if in_external_macro(cx.sess(), expr.span) || in_constant(cx, expr.hir_id) {
+ return;
+ }
+
+ 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))
{
- if in_external_macro(cx.sess(), expr.span) || in_constant(cx, expr.hir_id) {
- return;
- }
+ return;
+ }
- 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_type)
- && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::option_type))
- {
- return;
- }
+ 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,
+ };
- let expr_ctxt = expr.span.ctxt();
- let (some_expr, some_pat, pat_ref_count, is_wild_none) = match (
- try_parse_pattern(cx, arm1.pat, expr_ctxt),
- try_parse_pattern(cx, arm2.pat, expr_ctxt),
- ) {
- (Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count }))
- if is_none_expr(cx, arm1.body) =>
- {
- (arm2.body, pattern, ref_count, true)
- },
- (Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count }))
- if is_none_expr(cx, arm1.body) =>
- {
- (arm2.body, pattern, ref_count, false)
- },
- (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild))
- if is_none_expr(cx, arm2.body) =>
- {
- (arm1.body, pattern, ref_count, true)
- },
- (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None))
- if is_none_expr(cx, arm2.body) =>
- {
- (arm1.body, pattern, ref_count, false)
- },
- _ => return,
- };
+ // Top level or patterns aren't allowed in closures.
+ if matches!(some_pat.kind, PatKind::Or(_)) {
+ return;
+ }
- // Top level or patterns aren't allowed in closures.
- if matches!(some_pat.kind, PatKind::Or(_)) {
- return;
- }
+ let some_expr = match get_some_expr(cx, some_expr, false, expr_ctxt) {
+ Some(expr) => expr,
+ None => return,
+ };
- let some_expr = match get_some_expr(cx, some_expr, expr_ctxt) {
- Some(expr) => expr,
- None => return,
- };
+ // 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;
+ }
- // These two lints will go back and forth with each other.
- if cx.typeck_results().expr_ty(some_expr) == cx.tcx.types.unit
- && !is_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id)
- {
- return;
- }
+ // `map` won't perform any adjustments.
+ if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
+ return;
+ }
- // `map` won't perform any adjustments.
- if !cx.typeck_results().expr_adjustments(some_expr).is_empty() {
- return;
- }
+ // 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(|| ty_mutability));
- if !can_move_expr_to_closure(cx, some_expr) {
- return;
- }
+ let as_ref_str = match binding_ref {
+ Some(Mutability::Mut) => ".as_mut()",
+ Some(Mutability::Not) => ".as_ref()",
+ 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(|| ty_mutability));
+ 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,
+ Some(CaptureKind::Ref(Mutability::Not)) if binding_ref_mutability == Mutability::Mut => {
+ return;
+ },
+ Some(CaptureKind::Ref(Mutability::Not)) | None => (),
+ }
+ }
+ }
+ },
+ None => return,
+ };
- let as_ref_str = match binding_ref {
- Some(Mutability::Mut) => ".as_mut()",
- Some(Mutability::Not) => ".as_ref()",
- None => "",
- };
+ let mut app = Applicability::MachineApplicable;
- 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.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
+ format!("({})", scrutinee_str)
+ } else {
+ scrutinee_str.into()
+ };
- // 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.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
- format!("({})", scrutinee_str)
+ 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.ctxt() == some_expr.expr.span.ctxt();
+ then {
+ snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
} else {
- scrutinee_str.into()
- };
-
- let body_str = if let PatKind::Binding(annotation, _, some_binding, None) = some_pat.kind {
- match can_pass_as_func(cx, some_binding, some_expr) {
- Some(func) if func.span.ctxt() == some_expr.span.ctxt() => {
- snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
- },
- _ => {
- if match_var(some_expr, some_binding.name)
- && !is_allowed(cx, MATCH_AS_REF, expr.hir_id)
- && binding_ref.is_some()
- {
- return;
- }
+ if path_to_local_id(some_expr.expr, id)
+ && !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
+ && binding_ref.is_some()
+ {
+ return;
+ }
- // `ref` and `ref mut` annotations were handled earlier.
- let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
- "mut "
- } else {
- ""
- };
- format!(
- "|{}{}| {}",
- annotation,
- some_binding,
- snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
- )
- },
+ // `ref` and `ref mut` annotations were handled earlier.
+ let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
+ "mut "
+ } else {
+ ""
+ };
+ let expr_snip = snippet_with_context(cx, some_expr.expr.span, expr_ctxt, "..", &mut app).0;
+ if some_expr.needs_unsafe_block {
+ format!("|{}{}| unsafe {{ {} }}", annotation, some_binding, expr_snip)
+ } else {
+ format!("|{}{}| {}", annotation, some_binding, expr_snip)
+ }
}
- } else if !is_wild_none && explicit_ref.is_none() {
- // TODO: handle explicit reference annotations.
- format!(
- "|{}| {}",
- snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0,
- snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
- )
+ }
+ } 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;
+ let expr_snip = snippet_with_context(cx, some_expr.expr.span, expr_ctxt, "..", &mut app).0;
+ if some_expr.needs_unsafe_block {
+ format!("|{}| unsafe {{ {} }}", pat_snip, expr_snip)
} else {
- // Refutable bindings and mixed reference annotations can't be handled by `map`.
- return;
- };
+ format!("|{}| {}", pat_snip, expr_snip)
+ }
+ } else {
+ // Refutable bindings and mixed reference annotations can't be handled by `map`.
+ return;
+ };
- span_lint_and_sugg(
- cx,
- MANUAL_MAP,
- expr.span,
- "manual implementation of `Option::map`",
- "try this",
- if matches!(match_kind, MatchSource::IfLetDesugar { .. }) && is_else_clause(cx.tcx, expr) {
- format!("{{ {}{}.map({}) }}", scrutinee_str, as_ref_str, body_str)
- } else {
- format!("{}{}.map({})", scrutinee_str, as_ref_str, body_str)
- },
- app,
- );
- }
+ span_lint_and_sugg(
+ cx,
+ MANUAL_MAP,
+ expr.span,
+ "manual implementation of `Option::map`",
+ "try this",
+ if else_pat.is_none() && is_else_clause(cx.tcx, expr) {
+ format!("{{ {}{}.map({}) }}", scrutinee_str, as_ref_str, body_str)
+ } else {
+ format!("{}{}.map({})", scrutinee_str, as_ref_str, body_str)
+ },
+ app,
+ );
}
}
// 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(cx: &LateContext<'tcx>, binding: Ident, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+fn can_pass_as_func(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
match expr.kind {
ExprKind::Call(func, [arg])
- if match_var(arg, binding.name) && cx.typeck_results().expr_adjustments(arg).is_empty() =>
+ 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)
},
},
}
+struct SomeExpr<'tcx> {
+ expr: &'tcx Expr<'tcx>,
+ needs_unsafe_block: bool,
+}
+
// Try to parse into a recognized `Option` pattern.
// i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ctxt: SyntaxContext) -> Option<OptionPat<'tcx>> {
}
// Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
-fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ctxt: SyntaxContext) -> Option<&'tcx Expr<'tcx>> {
+fn get_some_expr(
+ cx: &LateContext<'tcx>,
+ expr: &'tcx Expr<'_>,
+ needs_unsafe_block: bool,
+ ctxt: SyntaxContext,
+) -> Option<SomeExpr<'tcx>> {
// TODO: Allow more complex expressions.
match expr.kind {
ExprKind::Call(
..
},
[arg],
- ) if ctxt == expr.span.ctxt() && is_lang_ctor(cx, qpath, OptionSome) => Some(arg),
+ ) if ctxt == expr.span.ctxt() && is_lang_ctor(cx, qpath, OptionSome) => Some(SomeExpr {
+ expr: arg,
+ needs_unsafe_block,
+ }),
ExprKind::Block(
Block {
stmts: [],
expr: Some(expr),
+ rules,
..
},
_,
- ) => get_some_expr(cx, expr, ctxt),
+ ) => get_some_expr(
+ cx,
+ expr,
+ needs_unsafe_block || *rules == BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
+ ctxt,
+ ),
_ => None,
}
}
// Checks for the `None` value.
fn is_none_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
- match expr.kind {
- ExprKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
- ExprKind::Block(
- Block {
- stmts: [],
- expr: Some(expr),
- ..
- },
- _,
- ) => is_none_expr(cx, expr),
- _ => false,
- }
+ matches!(peel_blocks(expr).kind, ExprKind::Path(ref qpath) if is_lang_ctor(cx, qpath, OptionNone))
}
projects / rust.git / blobdiff