Auto merge of #80790 - JohnTitor:rollup-js1noez, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #80012 (Add pointing const identifier when emitting E0435)
 - #80521 (MIR Inline is incompatible with coverage)
 - #80659 (Edit rustc_ast::tokenstream docs)
 - #80660 (Properly handle primitive disambiguators in rustdoc)
 - #80738 (Remove bottom margin from crate version when the docs sidebar is collapsed)
 - #80744 (rustdoc: Turn `next_def_id` comments into docs)
 - #80750 (Don't use to_string on Symbol in rustc_passes/check_attr.rs)
 - #80769 (Improve wording of parse doc)
 - #80780 (Return EOF_CHAR constant instead of magic char.)
 - #80784 (rustc_parse: Better spans for synthesized token streams)

Failed merges:

 - #80785 (rustc_ast_pretty: Remove `PrintState::insert_extra_parens`)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast/src/token.rs

@@ -771,7 +771,7 @@ impl fmt::Display for NonterminalKind {
 }
 
 impl Nonterminal {
-    fn span(&self) -> Span {
+    pub fn span(&self) -> Span {
         match self {
             NtItem(item) => item.span,
             NtBlock(block) => block.span,

compiler/rustc_ast/src/tokenstream.rs

@@ -1,15 +1,15 @@
 //! # Token Streams
 //!
 //! `TokenStream`s represent syntactic objects before they are converted into ASTs.
-//! A `TokenStream` is, roughly speaking, a sequence (eg stream) of `TokenTree`s,
-//! which are themselves a single `Token` or a `Delimited` subsequence of tokens.
+//! A `TokenStream` is, roughly speaking, a sequence of [`TokenTree`]s,
+//! which are themselves a single [`Token`] or a `Delimited` subsequence of tokens.
 //!
 //! ## Ownership
 //!
 //! `TokenStream`s are persistent data structures constructed as ropes with reference
 //! counted-children. In general, this means that calling an operation on a `TokenStream`
 //! (such as `slice`) produces an entirely new `TokenStream` from the borrowed reference to
-//! the original. This essentially coerces `TokenStream`s into 'views' of their subparts,
+//! the original. This essentially coerces `TokenStream`s into "views" of their subparts,
 //! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
 //! ownership of the original.
 
@@ -24,9 +24,9 @@ use smallvec::{smallvec, SmallVec};
 
 use std::{fmt, iter, mem};
 
-/// When the main rust parser encounters a syntax-extension invocation, it
-/// parses the arguments to the invocation as a token-tree. This is a very
-/// loose structure, such that all sorts of different AST-fragments can
+/// When the main Rust parser encounters a syntax-extension invocation, it
+/// parses the arguments to the invocation as a token tree. This is a very
+/// loose structure, such that all sorts of different AST fragments can
 /// be passed to syntax extensions using a uniform type.
 ///
 /// If the syntax extension is an MBE macro, it will attempt to match its
@@ -38,9 +38,9 @@ use std::{fmt, iter, mem};
 /// Nothing special happens to misnamed or misplaced `SubstNt`s.
 #[derive(Debug, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub enum TokenTree {
-    /// A single token
+    /// A single token.
     Token(Token),
-    /// A delimited sequence of token trees
+    /// A delimited sequence of token trees.
     Delimited(DelimSpan, DelimToken, TokenStream),
 }
 
@@ -62,7 +62,7 @@ where
 }
 
 impl TokenTree {
-    /// Checks if this TokenTree is equal to the other, regardless of span information.
+    /// Checks if this `TokenTree` is equal to the other, regardless of span information.
     pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
         match (self, other) {
             (TokenTree::Token(token), TokenTree::Token(token2)) => token.kind == token2.kind,
@@ -73,7 +73,7 @@ impl TokenTree {
         }
     }
 
-    /// Retrieves the TokenTree's span.
+    /// Retrieves the `TokenTree`'s span.
     pub fn span(&self) -> Span {
         match self {
             TokenTree::Token(token) => token.span,
@@ -140,7 +140,7 @@ impl CreateTokenStream for TokenStream {
     }
 }
 
-/// A lazy version of `TokenStream`, which defers creation
+/// A lazy version of [`TokenStream`], which defers creation
 /// of an actual `TokenStream` until it is needed.
 /// `Box` is here only to reduce the structure size.
 #[derive(Clone)]
@@ -188,11 +188,12 @@ impl<CTX> HashStable<CTX> for LazyTokenStream {
     }
 }
 
-/// A `TokenStream` is an abstract sequence of tokens, organized into `TokenTree`s.
+/// A `TokenStream` is an abstract sequence of tokens, organized into [`TokenTree`]s.
 ///
 /// The goal is for procedural macros to work with `TokenStream`s and `TokenTree`s
 /// instead of a representation of the abstract syntax tree.
-/// Today's `TokenTree`s can still contain AST via `token::Interpolated` for back-compat.
+/// Today's `TokenTree`s can still contain AST via `token::Interpolated` for
+/// backwards compatability.
 #[derive(Clone, Debug, Default, Encodable, Decodable)]
 pub struct TokenStream(pub(crate) Lrc<Vec<TreeAndSpacing>>);
 
@@ -429,7 +430,7 @@ impl TokenStreamBuilder {
     }
 }
 
-/// By-reference iterator over a `TokenStream`.
+/// By-reference iterator over a [`TokenStream`].
 #[derive(Clone)]
 pub struct CursorRef<'t> {
     stream: &'t TokenStream,
@@ -457,8 +458,8 @@ impl<'t> Iterator for CursorRef<'t> {
     }
 }
 
-/// Owning by-value iterator over a `TokenStream`.
-/// FIXME: Many uses of this can be replaced with by-reference iterator to avoid clones.
+/// Owning by-value iterator over a [`TokenStream`].
+// FIXME: Many uses of this can be replaced with by-reference iterator to avoid clones.
 #[derive(Clone)]
 pub struct Cursor {
     pub stream: TokenStream,

compiler/rustc_ast_lowering/src/lib.rs

@@ -206,8 +206,7 @@ pub trait ResolverAstLowering {
     ) -> LocalDefId;
 }
 
-type NtToTokenstream =
-    fn(&Nonterminal, &ParseSess, Span, CanSynthesizeMissingTokens) -> TokenStream;
+type NtToTokenstream = fn(&Nonterminal, &ParseSess, CanSynthesizeMissingTokens) -> TokenStream;
 
 /// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree,
 /// and if so, what meaning it has.
@@ -417,12 +416,7 @@ impl<'a> TokenStreamLowering<'a> {
     fn lower_token(&mut self, token: Token) -> TokenStream {
         match token.kind {
             token::Interpolated(nt) => {
-                let tts = (self.nt_to_tokenstream)(
-                    &nt,
-                    self.parse_sess,
-                    token.span,
-                    self.synthesize_tokens,
-                );
+                let tts = (self.nt_to_tokenstream)(&nt, self.parse_sess, self.synthesize_tokens);
                 TokenTree::Delimited(
                     DelimSpan::from_single(token.span),
                     DelimToken::NoDelim,

compiler/rustc_error_codes/src/error_codes/E0435.md

@@ -7,6 +7,12 @@ let foo = 42;
 let a: [u8; foo]; // error: attempt to use a non-constant value in a constant
 ```
 
+'constant' means 'a compile-time value'.
+
+More details can be found in the [Variables and Mutability] section of the book.
+
+[Variables and Mutability]: https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#differences-between-variables-and-constants
+
 To fix this error, please replace the value with a constant. Example:
 
 ```

compiler/rustc_expand/src/base.rs

@@ -141,7 +141,7 @@ impl Annotatable {
     }
 
     crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
-        nt_to_tokenstream(&self.into_nonterminal(), sess, DUMMY_SP, CanSynthesizeMissingTokens::No)
+        nt_to_tokenstream(&self.into_nonterminal(), sess, CanSynthesizeMissingTokens::No)
     }
 
     pub fn expect_item(self) -> P<ast::Item> {

compiler/rustc_expand/src/expand.rs

@@ -743,7 +743,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         AttrStyle::Inner => rustc_parse::fake_token_stream(
                             &self.cx.sess.parse_sess,
                             &item.into_nonterminal(),
-                            span,
                         ),
                     };
                     let attr_item = attr.unwrap_normal_item();

compiler/rustc_expand/src/proc_macro.rs

@@ -94,12 +94,7 @@ impl MultiItemModifier for ProcMacroDerive {
         let input = if item.pretty_printing_compatibility_hack() {
             TokenTree::token(token::Interpolated(Lrc::new(item)), DUMMY_SP).into()
         } else {
-            nt_to_tokenstream(
-                &item,
-                &ecx.sess.parse_sess,
-                DUMMY_SP,
-                CanSynthesizeMissingTokens::Yes,
-            )
+            nt_to_tokenstream(&item, &ecx.sess.parse_sess, CanSynthesizeMissingTokens::Yes)
         };
 
         let server = proc_macro_server::Rustc::new(ecx);

compiler/rustc_expand/src/proc_macro_server.rs

@@ -179,7 +179,7 @@ impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
                 {
                     TokenTree::Ident(Ident::new(sess, name.name, is_raw, name.span))
                 } else {
-                    let stream = nt_to_tokenstream(&nt, sess, span, CanSynthesizeMissingTokens::No);
+                    let stream = nt_to_tokenstream(&nt, sess, CanSynthesizeMissingTokens::No);
                     TokenTree::Group(Group {
                         delimiter: Delimiter::None,
                         stream,

compiler/rustc_lexer/src/cursor.rs

@@ -33,7 +33,7 @@ impl<'a> Cursor<'a> {
 
         #[cfg(not(debug_assertions))]
         {
-            '\0'
+            EOF_CHAR
         }
     }
 

compiler/rustc_mir/src/transform/inline.rs

@@ -41,6 +41,15 @@ impl<'tcx> MirPass<'tcx> for Inline {
             return;
         }
 
+        if tcx.sess.opts.debugging_opts.instrument_coverage {
+            // Since `Inline` happens after `InstrumentCoverage`, the function-specific coverage
+            // counters can be invalidated, such as by merging coverage counter statements from
+            // a pre-inlined function into a different function. This kind of change is invalid,
+            // so inlining must be skipped. Note: This check is performed here so inlining can
+            // be disabled without preventing other optimizations (regardless of `mir_opt_level`).
+            return;
+        }
+
         if inline(tcx, body) {
             debug!("running simplify cfg on {:?}", body.source);
             CfgSimplifier::new(body).simplify();

compiler/rustc_parse/src/lib.rs

@@ -236,7 +236,6 @@ pub fn parse_in<'a, T>(
 pub fn nt_to_tokenstream(
     nt: &Nonterminal,
     sess: &ParseSess,
-    span: Span,
     synthesize_tokens: CanSynthesizeMissingTokens,
 ) -> TokenStream {
     // A `Nonterminal` is often a parsed AST item. At this point we now
@@ -256,11 +255,9 @@ pub fn nt_to_tokenstream(
         |tokens: Option<&LazyTokenStream>| tokens.as_ref().map(|t| t.create_token_stream());
 
     let tokens = match *nt {
-        Nonterminal::NtItem(ref item) => {
-            prepend_attrs(sess, &item.attrs, nt, span, item.tokens.as_ref())
-        }
+        Nonterminal::NtItem(ref item) => prepend_attrs(sess, &item.attrs, nt, item.tokens.as_ref()),
         Nonterminal::NtBlock(ref block) => convert_tokens(block.tokens.as_ref()),
-        Nonterminal::NtStmt(ref stmt) => prepend_attrs(sess, stmt.attrs(), nt, span, stmt.tokens()),
+        Nonterminal::NtStmt(ref stmt) => prepend_attrs(sess, stmt.attrs(), nt, stmt.tokens()),
         Nonterminal::NtPat(ref pat) => convert_tokens(pat.tokens.as_ref()),
         Nonterminal::NtTy(ref ty) => convert_tokens(ty.tokens.as_ref()),
         Nonterminal::NtIdent(ident, is_raw) => {
@@ -277,31 +274,30 @@ pub fn nt_to_tokenstream(
             if expr.tokens.is_none() {
                 debug!("missing tokens for expr {:?}", expr);
             }
-            prepend_attrs(sess, &expr.attrs, nt, span, expr.tokens.as_ref())
+            prepend_attrs(sess, &expr.attrs, nt, expr.tokens.as_ref())
         }
     };
 
     if let Some(tokens) = tokens {
         return tokens;
     } else if matches!(synthesize_tokens, CanSynthesizeMissingTokens::Yes) {
-        return fake_token_stream(sess, nt, span);
+        return fake_token_stream(sess, nt);
     } else {
         let pretty = rustc_ast_pretty::pprust::nonterminal_to_string_no_extra_parens(&nt);
-        panic!("Missing tokens at {:?} for nt {:?}", span, pretty);
+        panic!("Missing tokens for nt {:?}", pretty);
     }
 }
 
-pub fn fake_token_stream(sess: &ParseSess, nt: &Nonterminal, span: Span) -> TokenStream {
+pub fn fake_token_stream(sess: &ParseSess, nt: &Nonterminal) -> TokenStream {
     let source = pprust::nonterminal_to_string(nt);
     let filename = FileName::macro_expansion_source_code(&source);
-    parse_stream_from_source_str(filename, source, sess, Some(span))
+    parse_stream_from_source_str(filename, source, sess, Some(nt.span()))
 }
 
 fn prepend_attrs(
     sess: &ParseSess,
     attrs: &[ast::Attribute],
     nt: &Nonterminal,
-    span: Span,
     tokens: Option<&tokenstream::LazyTokenStream>,
 ) -> Option<tokenstream::TokenStream> {
     if attrs.is_empty() {
@@ -312,7 +308,7 @@ fn prepend_attrs(
         // FIXME: Correctly handle tokens for inner attributes.
         // For now, we fall back to reparsing the original AST node
         if attr.style == ast::AttrStyle::Inner {
-            return Some(fake_token_stream(sess, nt, span));
+            return Some(fake_token_stream(sess, nt));
         }
         builder.push(attr.tokens());
     }

compiler/rustc_passes/src/check_attr.rs

@@ -359,7 +359,7 @@ impl CheckAttrVisitor<'tcx> {
             return false;
         }
         let item_name = self.tcx.hir().name(hir_id);
-        if item_name.to_string() == doc_alias {
+        if &*item_name.as_str() == doc_alias {
             self.tcx
                 .sess
                 .struct_span_err(

compiler/rustc_resolve/src/diagnostics.rs

@@ -398,13 +398,19 @@ impl<'a> Resolver<'a> {
                 err.help("use the `|| { ... }` closure form instead");
                 err
             }
-            ResolutionError::AttemptToUseNonConstantValueInConstant => {
+            ResolutionError::AttemptToUseNonConstantValueInConstant(ident, sugg) => {
                 let mut err = struct_span_err!(
                     self.session,
                     span,
                     E0435,
                     "attempt to use a non-constant value in a constant"
                 );
+                err.span_suggestion(
+                    ident.span,
+                    &sugg,
+                    "".to_string(),
+                    Applicability::MaybeIncorrect,
+                );
                 err.span_label(span, "non-constant value");
                 err
             }