Auto merge of rust-lang#7962 - Jarcho:fix_match_type_on_diagnostic_items, r=llogiq

Fix and improve `match_type_on_diagnostic_item`

This extracts the fix for the lint out of rust-lang#7647. There's still a couple of other functions to check, but at least this will get lint working again.

The two added util functions (`is_diagnostic_item` and `is_lang_item`) are needed to handle `DefId` for unit and tuple struct/variant constructors. The `rustc_diagnostic_item` and `lang` attributes are attached to the struct/variant `DefId`, but most of the time they are used through their constructors which have a different `DefId`. The two utility functions will check if the `DefId` is for a constructor and switch to the associated struct/variant `DefId`.

There does seem to be a bug on rustc's side where constructor `DefId`s from external crates seem to be returning `DefKind::Variant` instead of `DefKind::Ctor()`. There's a workaround put in right.

changelog: None

Author: bors

clippy_lints/src/await_holding_invalid.rs

@@ -6,7 +6,7 @@ use rustc_hir::{def::Res, AsyncGeneratorKind, Body, BodyId, GeneratorKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::GeneratorInteriorTypeCause;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::Span;
+use rustc_span::{sym, Span};
 
 use crate::utils::conf::DisallowedType;
 
@@ -276,9 +276,9 @@ fn emit_invalid_type(cx: &LateContext<'_>, span: Span, disallowed: &DisallowedTy
 }
 
 fn is_mutex_guard(cx: &LateContext<'_>, def_id: DefId) -> bool {
-    match_def_path(cx, def_id, &paths::MUTEX_GUARD)
-        || match_def_path(cx, def_id, &paths::RWLOCK_READ_GUARD)
-        || match_def_path(cx, def_id, &paths::RWLOCK_WRITE_GUARD)
+    cx.tcx.is_diagnostic_item(sym::MutexGuard, def_id)
+        || cx.tcx.is_diagnostic_item(sym::RwLockReadGuard, def_id)
+        || cx.tcx.is_diagnostic_item(sym::RwLockWriteGuard, def_id)
         || match_def_path(cx, def_id, &paths::PARKING_LOT_MUTEX_GUARD)
         || match_def_path(cx, def_id, &paths::PARKING_LOT_RWLOCK_READ_GUARD)
         || match_def_path(cx, def_id, &paths::PARKING_LOT_RWLOCK_WRITE_GUARD)

clippy_lints/src/if_then_some_else_none.rs

@@ -1,7 +1,9 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::eager_or_lazy::switch_to_eager_eval;
 use clippy_utils::source::snippet_with_macro_callsite;
-use clippy_utils::{contains_return, higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs, peel_blocks};
+use clippy_utils::{
+    contains_return, higher, is_else_clause, is_res_lang_ctor, meets_msrv, msrvs, path_res, peel_blocks,
+};
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{Expr, ExprKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -76,10 +78,8 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
             && let ExprKind::Block(then_block, _) = then.kind
             && let Some(then_expr) = then_block.expr
             && let ExprKind::Call(then_call, [then_arg]) = then_expr.kind
-            && let ExprKind::Path(ref then_call_qpath) = then_call.kind
-            && is_lang_ctor(cx, then_call_qpath, OptionSome)
-            && let ExprKind::Path(ref qpath) = peel_blocks(els).kind
-            && is_lang_ctor(cx, qpath, OptionNone)
+            && is_res_lang_ctor(cx, path_res(cx, then_call), OptionSome)
+            && is_res_lang_ctor(cx, path_res(cx, peel_blocks(els)), OptionNone)
             && !stmts_contains_early_return(then_block.stmts)
         {
             let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");

clippy_lints/src/infinite_iter.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint;
+use clippy_utils::higher;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
-use clippy_utils::{higher, match_def_path, path_def_id, paths};
 use rustc_hir::{BorrowKind, Closure, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -168,9 +168,16 @@ fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
         },
         ExprKind::Block(block, _) => block.expr.as_ref().map_or(Finite, |e| is_infinite(cx, e)),
         ExprKind::Box(e) | ExprKind::AddrOf(BorrowKind::Ref, _, e) => is_infinite(cx, e),
-        ExprKind::Call(path, _) => path_def_id(cx, path)
-            .map_or(false, |id| match_def_path(cx, id, &paths::ITER_REPEAT))
-            .into(),
+        ExprKind::Call(path, _) => {
+            if let ExprKind::Path(ref qpath) = path.kind {
+                cx.qpath_res(qpath, path.hir_id)
+                    .opt_def_id()
+                    .map_or(false, |id| cx.tcx.is_diagnostic_item(sym::iter_repeat, id))
+                    .into()
+            } else {
+                Finite
+            }
+        },
         ExprKind::Struct(..) => higher::Range::hir(expr).map_or(false, |r| r.end.is_none()).into(),
         _ => Finite,
     }

clippy_lints/src/inherent_to_string.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
-use clippy_utils::{get_trait_def_id, paths, return_ty, trait_ref_of_method};
+use clippy_utils::{return_ty, trait_ref_of_method};
 use if_chain::if_chain;
 use rustc_hir::{GenericParamKind, ImplItem, ImplItemKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -118,7 +118,10 @@ impl<'tcx> LateLintPass<'tcx> for InherentToString {
 }
 
 fn show_lint(cx: &LateContext<'_>, item: &ImplItem<'_>) {
-    let display_trait_id = get_trait_def_id(cx, &paths::DISPLAY_TRAIT).expect("Failed to get trait ID of `Display`!");
+    let display_trait_id = cx
+        .tcx
+        .get_diagnostic_item(sym::Display)
+        .expect("Failed to get trait ID of `Display`!");
 
     // Get the real type of 'self'
     let self_type = cx.tcx.fn_sig(item.def_id).input(0);

clippy_lints/src/lib.register_internal.rs

@@ -13,10 +13,10 @@ store.register_group(true, "clippy::internal", Some("clippy_internal"), vec![
     LintId::of(utils::internal_lints::INVALID_CLIPPY_VERSION_ATTRIBUTE),
     LintId::of(utils::internal_lints::INVALID_PATHS),
     LintId::of(utils::internal_lints::LINT_WITHOUT_LINT_PASS),
-    LintId::of(utils::internal_lints::MATCH_TYPE_ON_DIAGNOSTIC_ITEM),
     LintId::of(utils::internal_lints::MISSING_CLIPPY_VERSION_ATTRIBUTE),
     LintId::of(utils::internal_lints::MISSING_MSRV_ATTR_IMPL),
     LintId::of(utils::internal_lints::OUTER_EXPN_EXPN_DATA),
     LintId::of(utils::internal_lints::PRODUCE_ICE),
+    LintId::of(utils::internal_lints::UNNECESSARY_DEF_PATH),
     LintId::of(utils::internal_lints::UNNECESSARY_SYMBOL_STR),
 ])

clippy_lints/src/lib.register_lints.rs

@@ -24,8 +24,6 @@ store.register_lints(&[
     #[cfg(feature = "internal")]
     utils::internal_lints::LINT_WITHOUT_LINT_PASS,
     #[cfg(feature = "internal")]
-    utils::internal_lints::MATCH_TYPE_ON_DIAGNOSTIC_ITEM,
-    #[cfg(feature = "internal")]
     utils::internal_lints::MISSING_CLIPPY_VERSION_ATTRIBUTE,
     #[cfg(feature = "internal")]
     utils::internal_lints::MISSING_MSRV_ATTR_IMPL,
@@ -34,6 +32,8 @@ store.register_lints(&[
     #[cfg(feature = "internal")]
     utils::internal_lints::PRODUCE_ICE,
     #[cfg(feature = "internal")]
+    utils::internal_lints::UNNECESSARY_DEF_PATH,
+    #[cfg(feature = "internal")]
     utils::internal_lints::UNNECESSARY_SYMBOL_STR,
     almost_complete_letter_range::ALMOST_COMPLETE_LETTER_RANGE,
     approx_const::APPROX_CONSTANT,

clippy_lints/src/lib.rs

@@ -535,7 +535,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         store.register_late_pass(|_| Box::new(utils::internal_lints::InvalidPaths));
         store.register_late_pass(|_| Box::<utils::internal_lints::InterningDefinedSymbol>::default());
         store.register_late_pass(|_| Box::<utils::internal_lints::LintWithoutLintPass>::default());
-        store.register_late_pass(|_| Box::new(utils::internal_lints::MatchTypeOnDiagItem));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::UnnecessaryDefPath));
         store.register_late_pass(|_| Box::new(utils::internal_lints::OuterExpnDataPass));
         store.register_late_pass(|_| Box::new(utils::internal_lints::MsrvAttrImpl));
     }

clippy_lints/src/loops/manual_find.rs

@@ -1,7 +1,7 @@
 use super::utils::make_iterator_snippet;
 use super::MANUAL_FIND;
 use clippy_utils::{
-    diagnostics::span_lint_and_then, higher, is_lang_ctor, path_res, peel_blocks_with_stmt,
+    diagnostics::span_lint_and_then, higher, is_res_lang_ctor, path_res, peel_blocks_with_stmt,
     source::snippet_with_applicability, ty::implements_trait,
 };
 use if_chain::if_chain;
@@ -30,8 +30,8 @@ pub(super) fn check<'tcx>(
         if let [stmt] = block.stmts;
         if let StmtKind::Semi(semi) = stmt.kind;
         if let ExprKind::Ret(Some(ret_value)) = semi.kind;
-        if let ExprKind::Call(Expr { kind: ExprKind::Path(ctor), .. }, [inner_ret]) = ret_value.kind;
-        if is_lang_ctor(cx, ctor, LangItem::OptionSome);
+        if let ExprKind::Call(ctor, [inner_ret]) = ret_value.kind;
+        if is_res_lang_ctor(cx, path_res(cx, ctor), LangItem::OptionSome);
         if path_res(cx, inner_ret) == Res::Local(binding_id);
         if let Some((last_stmt, last_ret)) = last_stmt_and_ret(cx, expr);
         then {
@@ -143,8 +143,7 @@ fn last_stmt_and_ret<'tcx>(
         if let Some((_, Node::Block(block))) = parent_iter.next();
         if let Some((last_stmt, last_ret)) = extract(block);
         if last_stmt.hir_id == node_hir;
-        if let ExprKind::Path(path) = &last_ret.kind;
-        if is_lang_ctor(cx, path, LangItem::OptionNone);
+        if is_res_lang_ctor(cx, path_res(cx, last_ret), LangItem::OptionNone);
         if let Some((_, Node::Expr(_block))) = parent_iter.next();
         // This includes the function header
         if let Some((_, func)) = parent_iter.next();

clippy_lints/src/loops/manual_flatten.rs

@@ -3,13 +3,13 @@ use super::MANUAL_FLATTEN;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher;
 use clippy_utils::visitors::is_local_used;
-use clippy_utils::{is_lang_ctor, path_to_local_id, peel_blocks_with_stmt};
+use clippy_utils::{path_to_local_id, peel_blocks_with_stmt};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::LangItem::{OptionSome, ResultOk};
+use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Expr, Pat, PatKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty;
+use rustc_middle::ty::{self, DefIdTree};
 use rustc_span::source_map::Span;
 
 /// Check for unnecessary `if let` usage in a for loop where only the `Some` or `Ok` variant of the
@@ -30,8 +30,10 @@ pub(super) fn check<'tcx>(
         if path_to_local_id(let_expr, pat_hir_id);
         // Ensure the `if let` statement is for the `Some` variant of `Option` or the `Ok` variant of `Result`
         if let PatKind::TupleStruct(ref qpath, _, _) = let_pat.kind;
-        let some_ctor = is_lang_ctor(cx, qpath, OptionSome);
-        let ok_ctor = is_lang_ctor(cx, qpath, ResultOk);
+        if let Res::Def(DefKind::Ctor(..), ctor_id) = cx.qpath_res(qpath, let_pat.hir_id);
+        if let Some(variant_id) = cx.tcx.opt_parent(ctor_id);
+        let some_ctor = cx.tcx.lang_items().option_some_variant() == Some(variant_id);
+        let ok_ctor = cx.tcx.lang_items().result_ok_variant() == Some(variant_id);
         if some_ctor || ok_ctor;
         // Ensure expr in `if let` is not used afterwards
         if !is_local_used(cx, if_then, pat_hir_id);

clippy_lints/src/loops/while_let_on_iterator.rs

@@ -3,13 +3,12 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::higher;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{
-    get_enclosing_loop_or_multi_call_closure, is_refutable, is_trait_method, match_def_path, paths,
-    visitors::is_res_used,
+    get_enclosing_loop_or_multi_call_closure, is_refutable, is_res_lang_ctor, is_trait_method, visitors::is_res_used,
 };
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::{def::Res, Closure, Expr, ExprKind, HirId, Local, Mutability, PatKind, QPath, UnOp};
+use rustc_hir::{def::Res, Closure, Expr, ExprKind, HirId, LangItem, Local, Mutability, PatKind, UnOp};
 use rustc_lint::LateContext;
 use rustc_middle::hir::nested_filter::OnlyBodies;
 use rustc_middle::ty::adjustment::Adjust;
@@ -19,9 +18,8 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
     let (scrutinee_expr, iter_expr_struct, iter_expr, some_pat, loop_expr) = if_chain! {
         if let Some(higher::WhileLet { if_then, let_pat, let_expr }) = higher::WhileLet::hir(expr);
         // check for `Some(..)` pattern
-        if let PatKind::TupleStruct(QPath::Resolved(None, pat_path), some_pat, _) = let_pat.kind;
-        if let Res::Def(_, pat_did) = pat_path.res;
-        if match_def_path(cx, pat_did, &paths::OPTION_SOME);
+        if let PatKind::TupleStruct(ref pat_path, some_pat, _) = let_pat.kind;
+        if is_res_lang_ctor(cx, cx.qpath_res(pat_path, let_pat.hir_id), LangItem::OptionSome);
         // check for call to `Iterator::next`
         if let ExprKind::MethodCall(method_name, iter_expr, [], _) = let_expr.kind;
         if method_name.ident.name == sym::next;