map_unit_fn::OPTION_MAP_UNIT_FN,
matches::MATCH_AS_REF,
utils::{
- is_allowed, is_type_diagnostic_item, match_def_path, match_var, paths, peel_hir_expr_refs,
- peel_mid_ty_refs_is_mutable, snippet_with_applicability, span_lint_and_sugg,
+ can_partially_move_ty, is_allowed, is_type_diagnostic_item, match_def_path, match_var, paths,
+ peel_hir_expr_refs, peel_mid_ty_refs_is_mutable, snippet_with_applicability, snippet_with_context,
+ span_lint_and_sugg,
},
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_errors::Applicability;
-use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, Mutability, Pat, PatKind, QPath};
+use rustc_hir::{
+ def::Res,
+ intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor},
+ Arm, BindingAnnotation, Block, Expr, ExprKind, Mutability, Pat, PatKind, Path, QPath,
+};
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};
+use rustc_span::{
+ symbol::{sym, Ident},
+ SyntaxContext,
+};
declare_clippy_lint! {
/// **What it does:** Checks for usages of `match` which could be implemented using `map`
{
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)
+ 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 (some_expr, some_pat, pat_ref_count, is_wild_none) =
- match (try_parse_pattern(cx, arm1.pat), try_parse_pattern(cx, arm2.pat)) {
- (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,
- };
+ 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;
}
- let some_expr = match get_some_expr(cx, some_expr) {
+ let some_expr = match get_some_expr(cx, some_expr, expr_ctxt) {
Some(expr) => expr,
None => return,
};
return;
}
+ if !can_move_expr_to_closure(cx, some_expr) {
+ 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));
let mut app = Applicability::MachineApplicable;
- // Remove address-of expressions from the scrutinee. `as_ref` will be called,
- // the type is copyable, or the option is being passed by value.
+ // 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_applicability(cx, scrutinee.span, "_", &mut app);
- let scrutinee_str = if expr.precedence().order() < PREC_POSTFIX {
- // Parens are needed to chain method calls.
- format!("({})", scrutinee_str)
- } else {
- scrutinee_str.into()
- };
+ 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()
+ };
let body_str = if let PatKind::Binding(annotation, _, some_binding, None) = some_pat.kind {
- if let Some(func) = can_pass_as_func(cx, some_binding, some_expr) {
- snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
- } else {
- if match_var(some_expr, some_binding.name)
- && !is_allowed(cx, MATCH_AS_REF, expr.hir_id)
- && binding_ref.is_some()
- {
- return;
- }
+ 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;
+ }
- // `ref` and `ref mut` annotations were handled earlier.
- let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
- "mut "
- } else {
- ""
- };
- format!(
- "|{}{}| {}",
- annotation,
- some_binding,
- snippet_with_applicability(cx, some_expr.span, "..", &mut app)
- )
+ // `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)
+ )
+ },
}
} else if !is_wild_none && explicit_ref.is_none() {
// TODO: handle explicit reference annotations.
format!(
"|{}| {}",
- snippet_with_applicability(cx, some_pat.span, "..", &mut app),
- snippet_with_applicability(cx, some_expr.span, "..", &mut app)
+ snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app),
+ snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app)
)
} else {
// Refutable bindings and mixed reference annotations can't be handled by `map`.
}
}
+// Checks if the expression can be moved into a closure as is.
+fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
+ struct V<'cx, 'tcx> {
+ cx: &'cx LateContext<'tcx>,
+ make_closure: bool,
+ }
+ impl Visitor<'tcx> for V<'_, 'tcx> {
+ type Map = ErasedMap<'tcx>;
+ fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+ NestedVisitorMap::None
+ }
+
+ fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
+ match e.kind {
+ ExprKind::Break(..)
+ | ExprKind::Continue(_)
+ | ExprKind::Ret(_)
+ | ExprKind::Yield(..)
+ | ExprKind::InlineAsm(_)
+ | ExprKind::LlvmInlineAsm(_) => {
+ self.make_closure = false;
+ },
+ // Accessing a field of a local value can only be done if the type isn't
+ // partially moved.
+ ExprKind::Field(base_expr, _)
+ if matches!(
+ base_expr.kind,
+ ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
+ ) && can_partially_move_ty(self.cx, self.cx.typeck_results().expr_ty(base_expr)) =>
+ {
+ // TODO: check if the local has been partially moved. Assume it has for now.
+ self.make_closure = false;
+ return;
+ }
+ _ => (),
+ };
+ walk_expr(self, e);
+ }
+ }
+
+ let mut v = V { cx, make_closure: true };
+ v.visit_expr(expr);
+ v.make_closure
+}
+
// 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>> {
// 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<'_>) -> Option<OptionPat<'tcx>> {
- fn f(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ref_count: usize) -> Option<OptionPat<'tcx>> {
+fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ctxt: SyntaxContext) -> Option<OptionPat<'tcx>> {
+ fn f(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),
+ PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1, ctxt),
PatKind::Path(QPath::Resolved(None, path))
if path
.res
if path
.res
.opt_def_id()
- .map_or(false, |id| match_def_path(cx, id, &paths::OPTION_SOME)) =>
+ .map_or(false, |id| match_def_path(cx, id, &paths::OPTION_SOME))
+ && pat.span.ctxt() == ctxt =>
{
Some(OptionPat::Some { pattern, ref_count })
},
_ => None,
}
}
- f(cx, pat, 0)
+ f(cx, pat, 0, ctxt)
}
// Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
-fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ctxt: SyntaxContext) -> Option<&'tcx Expr<'tcx>> {
// TODO: Allow more complex expressions.
match expr.kind {
ExprKind::Call(
..
},
[arg],
- ) => {
+ ) if ctxt == expr.span.ctxt() => {
if match_def_path(cx, path.res.opt_def_id()?, &paths::OPTION_SOME) {
Some(arg)
} else {
..
},
_,
- ) => get_some_expr(cx, expr),
+ ) => get_some_expr(cx, expr, ctxt),
_ => None,
}
}
projects / rust.git / blobdiff