Rollup merge of #139039 - nnethercote:less-kw-Empty-4, r=petrochenkov

Reduce kw::Empty usage, part 4
Another step towards #137978.
r? `@petrochenkov`

Author: matthiaskrgr

compiler/rustc_passes/src/check_attr.rs

@@ -35,7 +35,7 @@ use rustc_session::lint::builtin::{
 UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,UNUSED_ATTRIBUTES,
 };
 use rustc_session::parse::feature_err;
-use rustc_span::{BytePos,DUMMY_SP,Span,Symbol, kw, sym};
+use rustc_span::{BytePos,DUMMY_SP,Span,Symbol,edition,kw, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::{TyCtxtInferExt,ValuePairs};
 use rustc_trait_selection::traits::ObligationCtxt;
@@ -1038,14 +1038,14 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
 // FIXME: Once rustdoc can handle URL conflicts on case insensitive file systems, we
 // can remove the `SelfTy` case here, remove `sym::SelfTy`, and update the
 // `#[doc(keyword = "SelfTy")` attribute in `library/std/src/keyword_docs.rs`.
- s <= kw::Union || s == sym::SelfTy
+ s.is_reserved(|| edition::LATEST_STABLE_EDITION) || s.is_weak() || s == sym::SelfTy
 }
 
-let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
-ifdoc_keyword == kw::Empty{
-self.doc_attr_str_error(meta,"keyword");
-return;
-}
+let doc_keyword = matchmeta.value_str(){
+Some(value)ifvalue != kw::Empty=> value,
+_ => returnself.doc_attr_str_error(meta,"keyword"),
+};
+
 let item_kind = matchself.tcx.hir_node(hir_id){
  hir::Node::Item(item) => Some(&item.kind),
  _ => None,

compiler/rustc_resolve/src/diagnostics.rs

@@ -1091,7 +1091,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 ));
 }
 Scope::BuiltinAttrs => {
-let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin(kw::Empty));
+let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin(sym::dummy));
 iffilter_fn(res){
  suggestions.extend(
 BUILTIN_ATTRIBUTES

compiler/rustc_span/src/hygiene.rs

@@ -1440,7 +1440,8 @@ pub fn decode_syntax_context<D: Decoder, F: FnOnce(&mut D, u32) -> SyntaxContext
 }
 }
 Entry::Vacant(entry) => {
-// We are the first thread to start decoding. Mark the current thread as being progress.
+// We are the first thread to start decoding. Mark the current thread as being
+// progress.
  context.local_in_progress.borrow_mut().insert(raw_id);
 
 // Allocate and store SyntaxContext id *before* calling the decoder function,

compiler/rustc_span/src/symbol.rs

@@ -131,7 +131,7 @@ symbols! {
 // tidy-alphabetical-end
 
 // Weak keywords, have special meaning only in specific contexts.
-// Matching predicates: none
+// Matching predicates: `is_weak`
 // tidy-alphabetical-start
 Auto:"auto",
 Builtin:"builtin",
@@ -2725,6 +2725,10 @@ impl Symbol {
  || self.is_unused_keyword_conditional(edition)
 }
 
+pubfnis_weak(self) -> bool{
+self >= kw::Auto && self <= kw::Yeet
+}
+
 /// A keyword or reserved identifier that can be used as a path segment.
 pubfnis_path_segment_keyword(self) -> bool{
 self == kw::Super

src/tools/clippy/clippy_lints/src/significant_drop_tightening.rs

@@ -79,10 +79,11 @@ impl<'tcx> LateLintPass<'tcx> for SignificantDropTightening<'tcx> {
 if apa.counter <= 1 || !apa.has_expensive_expr_after_last_attr{
 continue;
 }
+let first_bind_ident = apa.first_bind_ident.unwrap();
 span_lint_and_then(
  cx,
 SIGNIFICANT_DROP_TIGHTENING,
-apa.first_bind_ident.span,
+ first_bind_ident.span,
 "temporary with significant `Drop` can be early dropped",
  |diag| {
 match apa.counter{
@@ -91,13 +92,13 @@ impl<'tcx> LateLintPass<'tcx> for SignificantDropTightening<'tcx> {
 let indent = " ".repeat(indent_of(cx, apa.last_stmt_span).unwrap_or(0));
 let init_method = snippet(cx, apa.first_method_span,"..");
 let usage_method = snippet(cx, apa.last_method_span,"..");
-let stmt = if apa.last_bind_ident == Ident::empty(){
-format!("\n{indent}{init_method}.{usage_method};")
-}else{
+let stmt = ifletSome(last_bind_ident) = apa.last_bind_ident{
 format!(
 "\n{indent}let {} = {init_method}.{usage_method};",
- snippet(cx,apa.last_bind_ident.span,".."),
+ snippet(cx, last_bind_ident.span,".."),
 )
+}else{
+format!("\n{indent}{init_method}.{usage_method};")
 };
 
  diag.multipart_suggestion_verbose(
@@ -113,7 +114,7 @@ impl<'tcx> LateLintPass<'tcx> for SignificantDropTightening<'tcx> {
 format!(
 "\n{}drop({});",
 " ".repeat(indent_of(cx, apa.last_stmt_span).unwrap_or(0)),
-apa.first_bind_ident
+ first_bind_ident
 ),
 Applicability::MaybeIncorrect,
 );
@@ -124,7 +125,7 @@ impl<'tcx> LateLintPass<'tcx> for SignificantDropTightening<'tcx> {
  apa.first_block_span,
 format!(
 "temporary `{}` is currently being dropped at the end of its contained scope",
-apa.first_bind_ident
+ first_bind_ident
 ),
 );
 },
@@ -283,7 +284,7 @@ impl<'tcx> Visitor<'tcx> for StmtsChecker<'_, '_, '_, '_, 'tcx> {
 letmut apa = AuxParamsAttr{
 first_block_hir_id:self.ap.curr_block_hir_id,
 first_block_span:self.ap.curr_block_span,
-first_bind_ident: ident,
+first_bind_ident:Some(ident),
 first_method_span:{
 let expr_or_init = expr_or_init(self.cx, expr);
 iflet hir::ExprKind::MethodCall(_, local_expr, _, span) = expr_or_init.kind{
@@ -307,7 +308,7 @@ impl<'tcx> Visitor<'tcx> for StmtsChecker<'_, '_, '_, '_, 'tcx> {
 matchself.ap.curr_stmt.kind{
  hir::StmtKind::Let(local) => {
 iflet hir::PatKind::Binding(_, _, ident, _) = local.pat.kind{
- apa.last_bind_ident = ident;
+ apa.last_bind_ident = Some(ident);
 }
 ifletSome(local_init) = local.init
  && let hir::ExprKind::MethodCall(_, _, _, span) = local_init.kind
@@ -373,15 +374,15 @@ struct AuxParamsAttr {
 first_block_span:Span,
 /// The binding or variable that references the initial construction of the type marked with
 /// `#[has_significant_drop]`.
-first_bind_ident:Ident,
+first_bind_ident:Option<Ident>,
 /// Similar to `init_bind_ident` but encompasses the right-hand method call.
 first_method_span:Span,
 /// Similar to `init_bind_ident` but encompasses the whole contained statement.
 first_stmt_span:Span,
 
 /// The last visited binding or variable span within a block that had any referenced inner type
 /// marked with `#[has_significant_drop]`.
-last_bind_ident:Ident,
+last_bind_ident:Option<Ident>,
 /// Similar to `last_bind_span` but encompasses the right-hand method call.
 last_method_span:Span,
 /// Similar to `last_bind_span` but encompasses the whole contained statement.
@@ -395,10 +396,10 @@ impl Default for AuxParamsAttr {
 has_expensive_expr_after_last_attr:false,
 first_block_hir_id:HirId::INVALID,
 first_block_span:DUMMY_SP,
-first_bind_ident:Ident::empty(),
+first_bind_ident:None,
 first_method_span:DUMMY_SP,
 first_stmt_span:DUMMY_SP,
-last_bind_ident:Ident::empty(),
+last_bind_ident:None,
 last_method_span:DUMMY_SP,
 last_stmt_span:DUMMY_SP,
 }
@@ -413,7 +414,7 @@ fn dummy_stmt_expr<'any>(expr: &'any hir::Expr<'any>) -> hir::Stmt<'any> {
 }
 }
 
-fnhas_drop(expr:&hir::Expr<'_>,first_bind_ident:&Ident,lcx:&LateContext<'_>) -> bool{
+fnhas_drop(expr:&hir::Expr<'_>,first_bind_ident:&Option<Ident>,lcx:&LateContext<'_>) -> bool{
 iflet hir::ExprKind::Call(fun,[first_arg]) = expr.kind
  && let hir::ExprKind::Path(hir::QPath::Resolved(_, fun_path)) = &fun.kind
  && letRes::Def(DefKind::Fn, did) = fun_path.res
@@ -422,6 +423,7 @@ fn has_drop(expr: &hir::Expr<'_>, first_bind_ident: &Ident, lcx: &LateContext<'_
 let has_ident = |local_expr:&hir::Expr<'_>| {
 iflet hir::ExprKind::Path(hir::QPath::Resolved(_, arg_path)) = &local_expr.kind
  && let[first_arg_ps, ..] = arg_path.segments
+ && letSome(first_bind_ident) = first_bind_ident
  && &first_arg_ps.ident == first_bind_ident
 {
 true