--- /dev/null
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{is_refutable, peel_hir_pat_refs, recurse_or_patterns};
+use rustc_errors::Applicability;
+use rustc_hir::def::{CtorKind, DefKind, Res};
+use rustc_hir::{Arm, Expr, PatKind, PathSegment, QPath, Ty, TyKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, VariantDef};
+use rustc_span::sym;
+
+use super::{MATCH_WILDCARD_FOR_SINGLE_VARIANTS, WILDCARD_ENUM_MATCH_ARM};
+
+#[allow(clippy::too_many_lines)]
+pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
+ let ty = cx.typeck_results().expr_ty(ex).peel_refs();
+ let adt_def = match ty.kind() {
+ ty::Adt(adt_def, _)
+ if adt_def.is_enum()
+ && !(is_type_diagnostic_item(cx, ty, sym::Option) || is_type_diagnostic_item(cx, ty, sym::Result)) =>
+ {
+ adt_def
+ },
+ _ => return,
+ };
+
+ // First pass - check for violation, but don't do much book-keeping because this is hopefully
+ // the uncommon case, and the book-keeping is slightly expensive.
+ let mut wildcard_span = None;
+ let mut wildcard_ident = None;
+ let mut has_non_wild = false;
+ for arm in arms {
+ match peel_hir_pat_refs(arm.pat).0.kind {
+ PatKind::Wild => wildcard_span = Some(arm.pat.span),
+ PatKind::Binding(_, _, ident, None) => {
+ wildcard_span = Some(arm.pat.span);
+ wildcard_ident = Some(ident);
+ },
+ _ => has_non_wild = true,
+ }
+ }
+ let wildcard_span = match wildcard_span {
+ Some(x) if has_non_wild => x,
+ _ => return,
+ };
+
+ // Accumulate the variants which should be put in place of the wildcard because they're not
+ // already covered.
+ let has_hidden = adt_def.variants.iter().any(|x| is_hidden(cx, x));
+ let mut missing_variants: Vec<_> = adt_def.variants.iter().filter(|x| !is_hidden(cx, x)).collect();
+
+ let mut path_prefix = CommonPrefixSearcher::None;
+ for arm in arms {
+ // Guards mean that this case probably isn't exhaustively covered. Technically
+ // this is incorrect, as we should really check whether each variant is exhaustively
+ // covered by the set of guards that cover it, but that's really hard to do.
+ recurse_or_patterns(arm.pat, |pat| {
+ let path = match &peel_hir_pat_refs(pat).0.kind {
+ PatKind::Path(path) => {
+ #[allow(clippy::match_same_arms)]
+ let id = match cx.qpath_res(path, pat.hir_id) {
+ Res::Def(
+ DefKind::Const | DefKind::ConstParam | DefKind::AnonConst | DefKind::InlineConst,
+ _,
+ ) => return,
+ Res::Def(_, id) => id,
+ _ => return,
+ };
+ if arm.guard.is_none() {
+ missing_variants.retain(|e| e.ctor_def_id != Some(id));
+ }
+ path
+ },
+ PatKind::TupleStruct(path, patterns, ..) => {
+ if let Some(id) = cx.qpath_res(path, pat.hir_id).opt_def_id() {
+ if arm.guard.is_none() && patterns.iter().all(|p| !is_refutable(cx, p)) {
+ missing_variants.retain(|e| e.ctor_def_id != Some(id));
+ }
+ }
+ path
+ },
+ PatKind::Struct(path, patterns, ..) => {
+ if let Some(id) = cx.qpath_res(path, pat.hir_id).opt_def_id() {
+ if arm.guard.is_none() && patterns.iter().all(|p| !is_refutable(cx, p.pat)) {
+ missing_variants.retain(|e| e.def_id != id);
+ }
+ }
+ path
+ },
+ _ => return,
+ };
+ match path {
+ QPath::Resolved(_, path) => path_prefix.with_path(path.segments),
+ QPath::TypeRelative(
+ Ty {
+ kind: TyKind::Path(QPath::Resolved(_, path)),
+ ..
+ },
+ _,
+ ) => path_prefix.with_prefix(path.segments),
+ _ => (),
+ }
+ });
+ }
+
+ let format_suggestion = |variant: &VariantDef| {
+ format!(
+ "{}{}{}{}",
+ if let Some(ident) = wildcard_ident {
+ format!("{} @ ", ident.name)
+ } else {
+ String::new()
+ },
+ if let CommonPrefixSearcher::Path(path_prefix) = path_prefix {
+ let mut s = String::new();
+ for seg in path_prefix {
+ s.push_str(seg.ident.as_str());
+ s.push_str("::");
+ }
+ s
+ } else {
+ let mut s = cx.tcx.def_path_str(adt_def.did);
+ s.push_str("::");
+ s
+ },
+ variant.name,
+ match variant.ctor_kind {
+ CtorKind::Fn if variant.fields.len() == 1 => "(_)",
+ CtorKind::Fn => "(..)",
+ CtorKind::Const => "",
+ CtorKind::Fictive => "{ .. }",
+ }
+ )
+ };
+
+ match missing_variants.as_slice() {
+ [] => (),
+ [x] if !adt_def.is_variant_list_non_exhaustive() && !has_hidden => span_lint_and_sugg(
+ cx,
+ MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
+ wildcard_span,
+ "wildcard matches only a single variant and will also match any future added variants",
+ "try this",
+ format_suggestion(x),
+ Applicability::MaybeIncorrect,
+ ),
+ variants => {
+ let mut suggestions: Vec<_> = variants.iter().copied().map(format_suggestion).collect();
+ let message = if adt_def.is_variant_list_non_exhaustive() || has_hidden {
+ suggestions.push("_".into());
+ "wildcard matches known variants and will also match future added variants"
+ } else {
+ "wildcard match will also match any future added variants"
+ };
+
+ span_lint_and_sugg(
+ cx,
+ WILDCARD_ENUM_MATCH_ARM,
+ wildcard_span,
+ message,
+ "try this",
+ suggestions.join(" | "),
+ Applicability::MaybeIncorrect,
+ );
+ },
+ };
+}
+
+enum CommonPrefixSearcher<'a> {
+ None,
+ Path(&'a [PathSegment<'a>]),
+ Mixed,
+}
+impl<'a> CommonPrefixSearcher<'a> {
+ fn with_path(&mut self, path: &'a [PathSegment<'a>]) {
+ match path {
+ [path @ .., _] => self.with_prefix(path),
+ [] => (),
+ }
+ }
+
+ fn with_prefix(&mut self, path: &'a [PathSegment<'a>]) {
+ match self {
+ Self::None => *self = Self::Path(path),
+ Self::Path(self_path)
+ if path
+ .iter()
+ .map(|p| p.ident.name)
+ .eq(self_path.iter().map(|p| p.ident.name)) => {},
+ Self::Path(_) => *self = Self::Mixed,
+ Self::Mixed => (),
+ }
+ }
+}
+
+fn is_hidden(cx: &LateContext<'_>, variant_def: &VariantDef) -> bool {
+ let attrs = cx.tcx.get_attrs(variant_def.def_id);
+ clippy_utils::attrs::is_doc_hidden(attrs) || clippy_utils::attrs::is_unstable(attrs)
+}
use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
use clippy_utils::source::{indent_of, snippet, snippet_block, snippet_opt, snippet_with_applicability};
use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{
get_parent_expr, is_lang_ctor, is_refutable, is_wild, meets_msrv, msrvs, path_to_local_id, peel_blocks,
- peel_hir_pat_refs, recurse_or_patterns, strip_pat_refs,
+ strip_pat_refs,
};
use core::iter::once;
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::def::{CtorKind, DefKind, Res};
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_hir::{
- self as hir, Arm, BindingAnnotation, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Node, Pat,
- PatKind, PathSegment, QPath, TyKind,
+ Arm, BindingAnnotation, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Node, Pat, PatKind, QPath,
};
use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, VariantDef};
+use rustc_middle::ty;
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::sym;
mod match_bool;
mod match_like_matches;
mod match_same_arms;
+mod match_wild_enum;
mod match_wild_err_arm;
mod overlapping_arms;
mod redundant_pattern_match;
match_bool::check(cx, ex, arms, expr);
overlapping_arms::check(cx, ex, arms);
match_wild_err_arm::check(cx, ex, arms);
- check_wild_enum_match(cx, ex, arms);
+ match_wild_enum::check(cx, ex, arms);
check_match_as_ref(cx, ex, arms, expr);
check_wild_in_or_pats(cx, arms);
extract_msrv_attr!(LateContext);
}
-enum CommonPrefixSearcher<'a> {
- None,
- Path(&'a [PathSegment<'a>]),
- Mixed,
-}
-impl<'a> CommonPrefixSearcher<'a> {
- fn with_path(&mut self, path: &'a [PathSegment<'a>]) {
- match path {
- [path @ .., _] => self.with_prefix(path),
- [] => (),
- }
- }
-
- fn with_prefix(&mut self, path: &'a [PathSegment<'a>]) {
- match self {
- Self::None => *self = Self::Path(path),
- Self::Path(self_path)
- if path
- .iter()
- .map(|p| p.ident.name)
- .eq(self_path.iter().map(|p| p.ident.name)) => {},
- Self::Path(_) => *self = Self::Mixed,
- Self::Mixed => (),
- }
- }
-}
-
-fn is_hidden(cx: &LateContext<'_>, variant_def: &VariantDef) -> bool {
- let attrs = cx.tcx.get_attrs(variant_def.def_id);
- clippy_utils::attrs::is_doc_hidden(attrs) || clippy_utils::attrs::is_unstable(attrs)
-}
-
-#[allow(clippy::too_many_lines)]
-fn check_wild_enum_match(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
- let ty = cx.typeck_results().expr_ty(ex).peel_refs();
- let adt_def = match ty.kind() {
- ty::Adt(adt_def, _)
- if adt_def.is_enum()
- && !(is_type_diagnostic_item(cx, ty, sym::Option) || is_type_diagnostic_item(cx, ty, sym::Result)) =>
- {
- adt_def
- },
- _ => return,
- };
-
- // First pass - check for violation, but don't do much book-keeping because this is hopefully
- // the uncommon case, and the book-keeping is slightly expensive.
- let mut wildcard_span = None;
- let mut wildcard_ident = None;
- let mut has_non_wild = false;
- for arm in arms {
- match peel_hir_pat_refs(arm.pat).0.kind {
- PatKind::Wild => wildcard_span = Some(arm.pat.span),
- PatKind::Binding(_, _, ident, None) => {
- wildcard_span = Some(arm.pat.span);
- wildcard_ident = Some(ident);
- },
- _ => has_non_wild = true,
- }
- }
- let wildcard_span = match wildcard_span {
- Some(x) if has_non_wild => x,
- _ => return,
- };
-
- // Accumulate the variants which should be put in place of the wildcard because they're not
- // already covered.
- let has_hidden = adt_def.variants.iter().any(|x| is_hidden(cx, x));
- let mut missing_variants: Vec<_> = adt_def.variants.iter().filter(|x| !is_hidden(cx, x)).collect();
-
- let mut path_prefix = CommonPrefixSearcher::None;
- for arm in arms {
- // Guards mean that this case probably isn't exhaustively covered. Technically
- // this is incorrect, as we should really check whether each variant is exhaustively
- // covered by the set of guards that cover it, but that's really hard to do.
- recurse_or_patterns(arm.pat, |pat| {
- let path = match &peel_hir_pat_refs(pat).0.kind {
- PatKind::Path(path) => {
- #[allow(clippy::match_same_arms)]
- let id = match cx.qpath_res(path, pat.hir_id) {
- Res::Def(
- DefKind::Const | DefKind::ConstParam | DefKind::AnonConst | DefKind::InlineConst,
- _,
- ) => return,
- Res::Def(_, id) => id,
- _ => return,
- };
- if arm.guard.is_none() {
- missing_variants.retain(|e| e.ctor_def_id != Some(id));
- }
- path
- },
- PatKind::TupleStruct(path, patterns, ..) => {
- if let Some(id) = cx.qpath_res(path, pat.hir_id).opt_def_id() {
- if arm.guard.is_none() && patterns.iter().all(|p| !is_refutable(cx, p)) {
- missing_variants.retain(|e| e.ctor_def_id != Some(id));
- }
- }
- path
- },
- PatKind::Struct(path, patterns, ..) => {
- if let Some(id) = cx.qpath_res(path, pat.hir_id).opt_def_id() {
- if arm.guard.is_none() && patterns.iter().all(|p| !is_refutable(cx, p.pat)) {
- missing_variants.retain(|e| e.def_id != id);
- }
- }
- path
- },
- _ => return,
- };
- match path {
- QPath::Resolved(_, path) => path_prefix.with_path(path.segments),
- QPath::TypeRelative(
- hir::Ty {
- kind: TyKind::Path(QPath::Resolved(_, path)),
- ..
- },
- _,
- ) => path_prefix.with_prefix(path.segments),
- _ => (),
- }
- });
- }
-
- let format_suggestion = |variant: &VariantDef| {
- format!(
- "{}{}{}{}",
- if let Some(ident) = wildcard_ident {
- format!("{} @ ", ident.name)
- } else {
- String::new()
- },
- if let CommonPrefixSearcher::Path(path_prefix) = path_prefix {
- let mut s = String::new();
- for seg in path_prefix {
- s.push_str(seg.ident.as_str());
- s.push_str("::");
- }
- s
- } else {
- let mut s = cx.tcx.def_path_str(adt_def.did);
- s.push_str("::");
- s
- },
- variant.name,
- match variant.ctor_kind {
- CtorKind::Fn if variant.fields.len() == 1 => "(_)",
- CtorKind::Fn => "(..)",
- CtorKind::Const => "",
- CtorKind::Fictive => "{ .. }",
- }
- )
- };
-
- match missing_variants.as_slice() {
- [] => (),
- [x] if !adt_def.is_variant_list_non_exhaustive() && !has_hidden => span_lint_and_sugg(
- cx,
- MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
- wildcard_span,
- "wildcard matches only a single variant and will also match any future added variants",
- "try this",
- format_suggestion(x),
- Applicability::MaybeIncorrect,
- ),
- variants => {
- let mut suggestions: Vec<_> = variants.iter().copied().map(format_suggestion).collect();
- let message = if adt_def.is_variant_list_non_exhaustive() || has_hidden {
- suggestions.push("_".into());
- "wildcard matches known variants and will also match future added variants"
- } else {
- "wildcard match will also match any future added variants"
- };
-
- span_lint_and_sugg(
- cx,
- WILDCARD_ENUM_MATCH_ARM,
- wildcard_span,
- message,
- "try this",
- suggestions.join(" | "),
- Applicability::MaybeIncorrect,
- );
- },
- };
-}
-
fn check_match_ref_pats<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>)
where
'b: 'a,
projects / rust.git / commitdiff