Auto merge of rust-lang#105160 - nnethercote:rm-Lit-token_lit, r=petr…

…ochenkov

Remove `token::Lit` from `ast::MetaItemLit`.

Currently `ast::MetaItemLit` represents the literal kind twice. This PR removes that redundancy. Best reviewed one commit at a time.

r? `@petrochenkov`

compiler/rustc_ast/src/ast.rs

@@ -1734,8 +1734,10 @@ pub enum StrStyle {
 /// A literal in a meta item.
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct MetaItemLit {
-    /// The original literal token as written in source code.
-    pub token_lit: token::Lit,
+    /// The original literal as written in the source code.
+    pub symbol: Symbol,
+    /// The original suffix as written in the source code.
+    pub suffix: Option<Symbol>,
     /// The "semantic" representation of the literal lowered from the original tokens.
     /// Strings are unescaped, hexadecimal forms are eliminated, etc.
     pub kind: LitKind,
@@ -1745,13 +1747,14 @@ pub struct MetaItemLit {
 /// Similar to `MetaItemLit`, but restricted to string literals.
 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
 pub struct StrLit {
-    /// The original literal token as written in source code.
-    pub style: StrStyle,
+    /// The original literal as written in source code.
     pub symbol: Symbol,
+    /// The original suffix as written in source code.
     pub suffix: Option<Symbol>,
-    pub span: Span,
-    /// The unescaped "semantic" representation of the literal lowered from the original token.
+    /// The semantic (unescaped) representation of the literal.
     pub symbol_unescaped: Symbol,
+    pub style: StrStyle,
+    pub span: Span,
 }
 
 impl StrLit {
@@ -1797,8 +1800,9 @@ pub enum LitKind {
     /// A string literal (`"foo"`). The symbol is unescaped, and so may differ
     /// from the original token's symbol.
     Str(Symbol, StrStyle),
-    /// A byte string (`b"foo"`).
-    ByteStr(Lrc<[u8]>),
+    /// A byte string (`b"foo"`). Not stored as a symbol because it might be
+    /// non-utf8, and symbols only allow utf8 strings.
+    ByteStr(Lrc<[u8]>, StrStyle),
     /// A byte char (`b'f'`).
     Byte(u8),
     /// A character literal (`'a'`).
@@ -1823,7 +1827,7 @@ impl LitKind {
 
     /// Returns `true` if this literal is byte literal string.
     pub fn is_bytestr(&self) -> bool {
-        matches!(self, LitKind::ByteStr(_))
+        matches!(self, LitKind::ByteStr(..))
     }
 
     /// Returns `true` if this is a numeric literal.
@@ -3100,7 +3104,7 @@ mod size_asserts {
     static_assert_size!(ItemKind, 112);
     static_assert_size!(LitKind, 24);
     static_assert_size!(Local, 72);
-    static_assert_size!(MetaItemLit, 48);
+    static_assert_size!(MetaItemLit, 40);
     static_assert_size!(Param, 40);
     static_assert_size!(Pat, 88);
     static_assert_size!(Path, 24);

compiler/rustc_ast/src/attr/mod.rs

@@ -1,15 +1,15 @@
 //! Functions dealing with attributes and meta items.
 
-use crate::ast;
 use crate::ast::{AttrArgs, AttrArgsEq, AttrId, AttrItem, AttrKind, AttrStyle, AttrVec, Attribute};
 use crate::ast::{DelimArgs, Expr, ExprKind, LitKind, MetaItemLit};
 use crate::ast::{MacDelimiter, MetaItem, MetaItemKind, NestedMetaItem, NormalAttr};
-use crate::ast::{Path, PathSegment, StrStyle, DUMMY_NODE_ID};
+use crate::ast::{Path, PathSegment, DUMMY_NODE_ID};
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Delimiter, Token};
 use crate::tokenstream::{DelimSpan, Spacing, TokenTree};
 use crate::tokenstream::{LazyAttrTokenStream, TokenStream};
 use crate::util::comments;
+use crate::util::literal::escape_string_symbol;
 use rustc_data_structures::sync::WorkerLocal;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_span::symbol::{sym, Ident, Symbol};
@@ -321,18 +321,6 @@ impl Attribute {
     }
 }
 
-/* Constructors */
-
-pub fn mk_name_value_item_str(ident: Ident, str: Symbol, str_span: Span) -> MetaItem {
-    mk_name_value_item(ident, LitKind::Str(str, ast::StrStyle::Cooked), str_span)
-}
-
-pub fn mk_name_value_item(ident: Ident, kind: LitKind, lit_span: Span) -> MetaItem {
-    let lit = MetaItemLit { token_lit: kind.to_token_lit(), kind, span: lit_span };
-    let span = ident.span.to(lit_span);
-    MetaItem { path: Path::from_ident(ident), kind: MetaItemKind::NameValue(lit), span }
-}
-
 pub struct AttrIdGenerator(WorkerLocal<Cell<u32>>);
 
 #[cfg(debug_assertions)]
@@ -408,7 +396,7 @@ pub fn mk_attr_name_value_str(
     val: Symbol,
     span: Span,
 ) -> Attribute {
-    let lit = LitKind::Str(val, StrStyle::Cooked).to_token_lit();
+    let lit = token::Lit::new(token::Str, escape_string_symbol(val), None);
     let expr = P(Expr {
         id: DUMMY_NODE_ID,
         kind: ExprKind::Lit(lit),

compiler/rustc_ast/src/util/literal.rs

@@ -1,11 +1,31 @@
 //! Code related to parsing literals.
 
-use crate::ast::{self, LitKind, MetaItemLit};
+use crate::ast::{self, LitKind, MetaItemLit, StrStyle};
 use crate::token::{self, Token};
 use rustc_lexer::unescape::{byte_from_char, unescape_byte, unescape_char, unescape_literal, Mode};
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
-use std::ascii;
+use std::{ascii, fmt, str};
+
+// Escapes a string, represented as a symbol. Reuses the original symbol,
+// avoiding interning, if no changes are required.
+pub fn escape_string_symbol(symbol: Symbol) -> Symbol {
+    let s = symbol.as_str();
+    let escaped = s.escape_default().to_string();
+    if s == escaped { symbol } else { Symbol::intern(&escaped) }
+}
+
+// Escapes a char.
+pub fn escape_char_symbol(ch: char) -> Symbol {
+    let s: String = ch.escape_default().map(Into::<char>::into).collect();
+    Symbol::intern(&s)
+}
+
+// Escapes a byte string.
+pub fn escape_byte_str_symbol(bytes: &[u8]) -> Symbol {
+    let s = bytes.escape_ascii().to_string();
+    Symbol::intern(&s)
+}
 
 #[derive(Debug)]
 pub enum LitError {
@@ -115,9 +135,9 @@ impl LitKind {
                     }
                 });
                 error?;
-                LitKind::ByteStr(buf.into())
+                LitKind::ByteStr(buf.into(), StrStyle::Cooked)
             }
-            token::ByteStrRaw(_) => {
+            token::ByteStrRaw(n) => {
                 let s = symbol.as_str();
                 let bytes = if s.contains('\r') {
                     let mut buf = Vec::with_capacity(s.len());
@@ -136,69 +156,95 @@ impl LitKind {
                     symbol.to_string().into_bytes()
                 };
 
-                LitKind::ByteStr(bytes.into())
+                LitKind::ByteStr(bytes.into(), StrStyle::Raw(n))
             }
             token::Err => LitKind::Err,
         })
     }
+}
 
-    /// Attempts to recover a token from semantic literal.
-    /// This function is used when the original token doesn't exist (e.g. the literal is created
-    /// by an AST-based macro) or unavailable (e.g. from HIR pretty-printing).
-    pub fn to_token_lit(&self) -> token::Lit {
-        let (kind, symbol, suffix) = match *self {
-            LitKind::Str(symbol, ast::StrStyle::Cooked) => {
-                // Don't re-intern unless the escaped string is different.
-                let s = symbol.as_str();
-                let escaped = s.escape_default().to_string();
-                let symbol = if s == escaped { symbol } else { Symbol::intern(&escaped) };
-                (token::Str, symbol, None)
-            }
-            LitKind::Str(symbol, ast::StrStyle::Raw(n)) => (token::StrRaw(n), symbol, None),
-            LitKind::ByteStr(ref bytes) => {
-                let string = bytes.escape_ascii().to_string();
-                (token::ByteStr, Symbol::intern(&string), None)
+impl fmt::Display for LitKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            LitKind::Byte(b) => {
+                let b: String = ascii::escape_default(b).map(Into::<char>::into).collect();
+                write!(f, "b'{}'", b)?;
             }
-            LitKind::Byte(byte) => {
-                let string: String = ascii::escape_default(byte).map(Into::<char>::into).collect();
-                (token::Byte, Symbol::intern(&string), None)
+            LitKind::Char(ch) => write!(f, "'{}'", escape_char_symbol(ch))?,
+            LitKind::Str(sym, StrStyle::Cooked) => write!(f, "\"{}\"", escape_string_symbol(sym))?,
+            LitKind::Str(sym, StrStyle::Raw(n)) => write!(
+                f,
+                "r{delim}\"{string}\"{delim}",
+                delim = "#".repeat(n as usize),
+                string = sym
+            )?,
+            LitKind::ByteStr(ref bytes, StrStyle::Cooked) => {
+                write!(f, "b\"{}\"", escape_byte_str_symbol(bytes))?
             }
-            LitKind::Char(ch) => {
-                let string: String = ch.escape_default().map(Into::<char>::into).collect();
-                (token::Char, Symbol::intern(&string), None)
+            LitKind::ByteStr(ref bytes, StrStyle::Raw(n)) => {
+                // Unwrap because raw byte string literals can only contain ASCII.
+                let symbol = str::from_utf8(bytes).unwrap();
+                write!(
+                    f,
+                    "br{delim}\"{string}\"{delim}",
+                    delim = "#".repeat(n as usize),
+                    string = symbol
+                )?;
             }
             LitKind::Int(n, ty) => {
-                let suffix = match ty {
-                    ast::LitIntType::Unsigned(ty) => Some(ty.name()),
-                    ast::LitIntType::Signed(ty) => Some(ty.name()),
-                    ast::LitIntType::Unsuffixed => None,
-                };
-                (token::Integer, sym::integer(n), suffix)
+                write!(f, "{}", n)?;
+                match ty {
+                    ast::LitIntType::Unsigned(ty) => write!(f, "{}", ty.name())?,
+                    ast::LitIntType::Signed(ty) => write!(f, "{}", ty.name())?,
+                    ast::LitIntType::Unsuffixed => {}
+                }
             }
             LitKind::Float(symbol, ty) => {
-                let suffix = match ty {
-                    ast::LitFloatType::Suffixed(ty) => Some(ty.name()),
-                    ast::LitFloatType::Unsuffixed => None,
-                };
-                (token::Float, symbol, suffix)
+                write!(f, "{}", symbol)?;
+                match ty {
+                    ast::LitFloatType::Suffixed(ty) => write!(f, "{}", ty.name())?,
+                    ast::LitFloatType::Unsuffixed => {}
+                }
             }
-            LitKind::Bool(value) => {
-                let symbol = if value { kw::True } else { kw::False };
-                (token::Bool, symbol, None)
+            LitKind::Bool(b) => write!(f, "{}", if b { "true" } else { "false" })?,
+            LitKind::Err => {
+                // This only shows up in places like `-Zunpretty=hir` output, so we
+                // don't bother to produce something useful.
+                write!(f, "<bad-literal>")?;
             }
-            // This only shows up in places like `-Zunpretty=hir` output, so we
-            // don't bother to produce something useful.
-            LitKind::Err => (token::Err, Symbol::intern("<bad-literal>"), None),
-        };
+        }
 
-        token::Lit::new(kind, symbol, suffix)
+        Ok(())
     }
 }
 
 impl MetaItemLit {
-    /// Converts token literal into a meta item literal.
+    /// Converts a token literal into a meta item literal.
     pub fn from_token_lit(token_lit: token::Lit, span: Span) -> Result<MetaItemLit, LitError> {
-        Ok(MetaItemLit { token_lit, kind: LitKind::from_token_lit(token_lit)?, span })
+        Ok(MetaItemLit {
+            symbol: token_lit.symbol,
+            suffix: token_lit.suffix,
+            kind: LitKind::from_token_lit(token_lit)?,
+            span,
+        })
+    }
+
+    /// Cheaply converts a meta item literal into a token literal.
+    pub fn as_token_lit(&self) -> token::Lit {
+        let kind = match self.kind {
+            LitKind::Bool(_) => token::Bool,
+            LitKind::Str(_, ast::StrStyle::Cooked) => token::Str,
+            LitKind::Str(_, ast::StrStyle::Raw(n)) => token::StrRaw(n),
+            LitKind::ByteStr(_, ast::StrStyle::Cooked) => token::ByteStr,
+            LitKind::ByteStr(_, ast::StrStyle::Raw(n)) => token::ByteStrRaw(n),
+            LitKind::Byte(_) => token::Byte,
+            LitKind::Char(_) => token::Char,
+            LitKind::Int(..) => token::Integer,
+            LitKind::Float(..) => token::Float,
+            LitKind::Err => token::Err,
+        };
+
+        token::Lit::new(kind, self.symbol, self.suffix)
     }
 
     /// Converts an arbitrary token into meta item literal.

compiler/rustc_ast_lowering/src/expr.rs

@@ -97,7 +97,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::IncludedBytes(bytes) => hir::ExprKind::Lit(respan(
                     self.lower_span(e.span),
-                    LitKind::ByteStr(bytes.clone()),
+                    LitKind::ByteStr(bytes.clone(), StrStyle::Cooked),
                 )),
                 ExprKind::Cast(expr, ty) => {
                     let expr = self.lower_expr(expr);

compiler/rustc_ast_lowering/src/lib.rs

@@ -958,7 +958,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     lit
                 } else {
                     MetaItemLit {
-                        token_lit: token::Lit::new(token::LitKind::Err, kw::Empty, None),
+                        symbol: kw::Empty,
+                        suffix: None,
                         kind: LitKind::Err,
                         span: DUMMY_SP,
                     }

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -376,7 +376,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     }
 
     fn print_meta_item_lit(&mut self, lit: &ast::MetaItemLit) {
-        self.print_token_literal(lit.token_lit, lit.span)
+        self.print_token_literal(lit.as_token_lit(), lit.span)
     }
 
     fn print_token_literal(&mut self, token_lit: token::Lit, span: Span) {

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -2,6 +2,8 @@ use crate::pp::Breaks::Inconsistent;
 use crate::pprust::state::{AnnNode, IterDelimited, PrintState, State, INDENT_UNIT};
 
 use rustc_ast::ptr::P;
+use rustc_ast::token;
+use rustc_ast::util::literal::escape_byte_str_symbol;
 use rustc_ast::util::parser::{self, AssocOp, Fixity};
 use rustc_ast::{self as ast, BlockCheckMode};
 
@@ -323,7 +325,7 @@ impl<'a> State<'a> {
                 self.print_token_literal(*token_lit, expr.span);
             }
             ast::ExprKind::IncludedBytes(bytes) => {
-                let lit = ast::LitKind::ByteStr(bytes.clone()).to_token_lit();
+                let lit = token::Lit::new(token::ByteStr, escape_byte_str_symbol(bytes), None);
                 self.print_token_literal(lit, expr.span)
             }
             ast::ExprKind::Cast(expr, ty) => {

compiler/rustc_builtin_macros/src/concat_bytes.rs

@@ -69,7 +69,7 @@ fn invalid_type_err(
         Ok(ast::LitKind::Int(_, _)) => {
             cx.span_err(span, "numeric literal is not a `u8`");
         }
-        Ok(ast::LitKind::ByteStr(_) | ast::LitKind::Byte(_)) => unreachable!(),
+        Ok(ast::LitKind::ByteStr(..) | ast::LitKind::Byte(_)) => unreachable!(),
         Err(err) => {
             report_lit_error(&cx.sess.parse_sess, err, token_lit, span);
         }
@@ -97,7 +97,7 @@ fn handle_array_element(
             )) if val <= u8::MAX.into() => Some(val as u8),
 
             Ok(ast::LitKind::Byte(val)) => Some(val),
-            Ok(ast::LitKind::ByteStr(_)) => {
+            Ok(ast::LitKind::ByteStr(..)) => {
                 if !*has_errors {
                     cx.struct_span_err(expr.span, "cannot concatenate doubly nested array")
                         .note("byte strings are treated as arrays of bytes")
@@ -174,7 +174,7 @@ pub fn expand_concat_bytes(
                 Ok(ast::LitKind::Byte(val)) => {
                     accumulator.push(val);
                 }
-                Ok(ast::LitKind::ByteStr(ref bytes)) => {
+                Ok(ast::LitKind::ByteStr(ref bytes, _)) => {
                     accumulator.extend_from_slice(&bytes);
                 }
                 _ => {

compiler/rustc_builtin_macros/src/derive.rs

@@ -1,7 +1,7 @@
 use crate::cfg_eval::cfg_eval;
 
 use rustc_ast as ast;
-use rustc_ast::{token, GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
+use rustc_ast::{GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier};
 use rustc_feature::AttributeTemplate;
@@ -130,9 +130,11 @@ fn report_bad_target(sess: &Session, item: &Annotatable, span: Span) -> bool {
 }
 
 fn report_unexpected_meta_item_lit(sess: &Session, lit: &ast::MetaItemLit) {
-    let help_msg = match lit.token_lit.kind {
-        token::Str if rustc_lexer::is_ident(lit.token_lit.symbol.as_str()) => {
-            format!("try using `#[derive({})]`", lit.token_lit.symbol)
+    let help_msg = match lit.kind {
+        ast::LitKind::Str(_, ast::StrStyle::Cooked)
+            if rustc_lexer::is_ident(lit.symbol.as_str()) =>
+        {
+            format!("try using `#[derive({})]`", lit.symbol)
         }
         _ => "for example, write `#[derive(Debug)]` for `Debug`".to_string(),
     };

compiler/rustc_expand/src/base.rs

@@ -1231,7 +1231,7 @@ pub fn expr_to_spanned_string<'a>(
     Err(match expr.kind {
         ast::ExprKind::Lit(token_lit) => match ast::LitKind::from_token_lit(token_lit) {
             Ok(ast::LitKind::Str(s, style)) => return Ok((s, style, expr.span)),
-            Ok(ast::LitKind::ByteStr(_)) => {
+            Ok(ast::LitKind::ByteStr(..)) => {
                 let mut err = cx.struct_span_err(expr.span, err_msg);
                 let span = expr.span.shrink_to_lo();
                 err.span_suggestion(