Rollup merge of #104804 - nnethercote:MetaItemLit, r=petrochenkov

Rename `ast::Lit` as `ast::MetaItemLit`.

And some other literal cleanups.

r? `@petrochenkov`

compiler/rustc_ast/src/ast.rs

@@ -13,7 +13,7 @@
 //! - [`FnDecl`], [`FnHeader`] and [`Param`]: Metadata associated with a function declaration.
 //! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
 //! - [`EnumDef`] and [`Variant`]: Enum declaration.
-//! - [`Lit`] and [`LitKind`]: Literal expressions.
+//! - [`MetaItemLit`] and [`LitKind`]: Literal expressions.
 //! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`], [`MacDelimiter`]: Macro definition and invocation.
 //! - [`Attribute`]: Metadata associated with item.
 //! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
@@ -489,7 +489,7 @@ pub enum NestedMetaItem {
     /// A literal.
     ///
     /// E.g., `"foo"`, `64`, `true`.
-    Literal(Lit),
+    Lit(MetaItemLit),
 }
 
 /// A spanned compile-time attribute item.
@@ -518,7 +518,7 @@ pub enum MetaItemKind {
     /// Name value meta item.
     ///
     /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
-    NameValue(Lit),
+    NameValue(MetaItemLit),
 }
 
 /// A block (`{ .. }`).
@@ -1599,12 +1599,12 @@ pub enum AttrArgs {
 }
 
 // The RHS of an `AttrArgs::Eq` starts out as an expression. Once macro
-// expansion is completed, all cases end up either as a literal, which is the
-// form used after lowering to HIR, or as an error.
+// expansion is completed, all cases end up either as a meta item literal,
+// which is the form used after lowering to HIR, or as an error.
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum AttrArgsEq {
     Ast(P<Expr>),
-    Hir(Lit),
+    Hir(MetaItemLit),
 }
 
 impl AttrArgs {
@@ -1726,19 +1726,18 @@ pub enum StrStyle {
     Raw(u8),
 }
 
-/// An AST literal.
+/// A literal in a meta item.
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
-pub struct Lit {
+pub struct MetaItemLit {
     /// The original literal token as written in source code.
     pub token_lit: token::Lit,
     /// The "semantic" representation of the literal lowered from the original tokens.
     /// Strings are unescaped, hexadecimal forms are eliminated, etc.
-    /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
     pub kind: LitKind,
     pub span: Span,
 }
 
-/// Same as `Lit`, but restricted to string literals.
+/// 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.
@@ -1747,7 +1746,6 @@ pub struct StrLit {
     pub suffix: Option<Symbol>,
     pub span: Span,
     /// The unescaped "semantic" representation of the literal lowered from the original token.
-    /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
     pub symbol_unescaped: Symbol,
 }
 
@@ -1783,6 +1781,8 @@ pub enum LitFloatType {
     Unsuffixed,
 }
 
+/// This type is used within both `ast::MetaItemLit` and `hir::Lit`.
+///
 /// Note that the entire literal (including the suffix) is considered when
 /// deciding the `LitKind`. This means that float literals like `1f32` are
 /// classified by this type as `Float`. This is different to `token::LitKind`
@@ -3096,9 +3096,9 @@ mod size_asserts {
     static_assert_size!(Impl, 184);
     static_assert_size!(Item, 184);
     static_assert_size!(ItemKind, 112);
-    static_assert_size!(Lit, 48);
     static_assert_size!(LitKind, 24);
     static_assert_size!(Local, 72);
+    static_assert_size!(MetaItemLit, 48);
     static_assert_size!(Param, 40);
     static_assert_size!(Pat, 88);
     static_assert_size!(Path, 24);

compiler/rustc_ast/src/attr/mod.rs

@@ -2,7 +2,7 @@
 
 use crate::ast;
 use crate::ast::{AttrArgs, AttrArgsEq, AttrId, AttrItem, AttrKind, AttrStyle, Attribute};
-use crate::ast::{DelimArgs, Lit, LitKind};
+use crate::ast::{DelimArgs, LitKind, MetaItemLit};
 use crate::ast::{MacDelimiter, MetaItem, MetaItemKind, NestedMetaItem};
 use crate::ast::{Path, PathSegment};
 use crate::ptr::P;
@@ -50,10 +50,10 @@ impl NestedMetaItem {
         }
     }
 
-    /// Returns the `Lit` if `self` is a `NestedMetaItem::Literal`s.
-    pub fn literal(&self) -> Option<&Lit> {
+    /// Returns the `MetaItemLit` if `self` is a `NestedMetaItem::Literal`s.
+    pub fn lit(&self) -> Option<&MetaItemLit> {
         match self {
-            NestedMetaItem::Literal(lit) => Some(lit),
+            NestedMetaItem::Lit(lit) => Some(lit),
             _ => None,
         }
     }
@@ -78,12 +78,12 @@ impl NestedMetaItem {
     }
 
     /// Returns a name and single literal value tuple of the `MetaItem`.
-    pub fn name_value_literal(&self) -> Option<(Symbol, &Lit)> {
+    pub fn name_value_literal(&self) -> Option<(Symbol, &MetaItemLit)> {
         self.meta_item().and_then(|meta_item| {
             meta_item.meta_item_list().and_then(|meta_item_list| {
                 if meta_item_list.len() == 1
                     && let Some(ident) = meta_item.ident()
-                    && let Some(lit) = meta_item_list[0].literal()
+                    && let Some(lit) = meta_item_list[0].lit()
                 {
                     return Some((ident.name, lit));
                 }
@@ -179,7 +179,7 @@ impl MetaItem {
     ///     #[attribute(name = "value")]
     ///                 ^^^^^^^^^^^^^^
     /// ```
-    pub fn name_value_literal(&self) -> Option<&Lit> {
+    pub fn name_value_literal(&self) -> Option<&MetaItemLit> {
         match &self.kind {
             MetaItemKind::NameValue(v) => Some(v),
             _ => None,
@@ -334,7 +334,7 @@ pub fn mk_name_value_item_str(ident: Ident, str: Symbol, str_span: Span) -> Meta
 }
 
 pub fn mk_name_value_item(ident: Ident, lit_kind: LitKind, lit_span: Span) -> MetaItem {
-    let lit = Lit::from_lit_kind(lit_kind, lit_span);
+    let lit = MetaItemLit::from_lit_kind(lit_kind, lit_span);
     let span = ident.span.to(lit_span);
     MetaItem { path: Path::from_ident(ident), span, kind: MetaItemKind::NameValue(lit) }
 }
@@ -604,7 +604,7 @@ impl MetaItemKind {
                 MetaItemKind::name_value_from_tokens(&mut inner_tokens.into_trees())
             }
             Some(TokenTree::Token(token, _)) => {
-                Lit::from_token(&token).map(MetaItemKind::NameValue)
+                MetaItemLit::from_token(&token).map(MetaItemKind::NameValue)
             }
             _ => None,
         }
@@ -622,7 +622,7 @@ impl MetaItemKind {
             AttrArgs::Eq(_, AttrArgsEq::Ast(expr)) => match expr.kind {
                 ast::ExprKind::Lit(token_lit) => {
                     // Turn failures to `None`, we'll get parse errors elsewhere.
-                    Lit::from_token_lit(token_lit, expr.span)
+                    MetaItemLit::from_token_lit(token_lit, expr.span)
                         .ok()
                         .map(|lit| MetaItemKind::NameValue(lit))
                 }
@@ -655,14 +655,14 @@ impl NestedMetaItem {
     pub fn span(&self) -> Span {
         match self {
             NestedMetaItem::MetaItem(item) => item.span,
-            NestedMetaItem::Literal(lit) => lit.span,
+            NestedMetaItem::Lit(lit) => lit.span,
         }
     }
 
     fn token_trees(&self) -> Vec<TokenTree> {
         match self {
             NestedMetaItem::MetaItem(item) => item.token_trees(),
-            NestedMetaItem::Literal(lit) => {
+            NestedMetaItem::Lit(lit) => {
                 vec![TokenTree::Token(lit.to_token(), Spacing::Alone)]
             }
         }
@@ -674,10 +674,10 @@ impl NestedMetaItem {
     {
         match tokens.peek() {
             Some(TokenTree::Token(token, _))
-                if let Some(lit) = Lit::from_token(token) =>
+                if let Some(lit) = MetaItemLit::from_token(token) =>
             {
                 tokens.next();
-                return Some(NestedMetaItem::Literal(lit));
+                return Some(NestedMetaItem::Lit(lit));
             }
             Some(TokenTree::Delimited(_, Delimiter::Invisible, inner_tokens)) => {
                 let inner_tokens = inner_tokens.clone();

compiler/rustc_ast/src/mut_visit.rs

@@ -628,7 +628,7 @@ pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T
 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
     match li {
         NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
-        NestedMetaItem::Literal(_lit) => {}
+        NestedMetaItem::Lit(_lit) => {}
     }
 }
 

compiler/rustc_ast/src/util/literal.rs

@@ -1,8 +1,7 @@
 //! Code related to parsing literals.
 
-use crate::ast::{self, Lit, LitKind};
+use crate::ast::{self, LitKind, MetaItemLit};
 use crate::token::{self, Token};
-use rustc_data_structures::sync::Lrc;
 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;
@@ -196,33 +195,26 @@ impl LitKind {
     }
 }
 
-impl Lit {
-    /// Converts literal token into an AST literal.
-    pub fn from_token_lit(token_lit: token::Lit, span: Span) -> Result<Lit, LitError> {
-        Ok(Lit { token_lit, kind: LitKind::from_token_lit(token_lit)?, span })
+impl MetaItemLit {
+    /// Converts 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 })
     }
 
-    /// Converts an arbitrary token into an AST literal.
-    pub fn from_token(token: &Token) -> Option<Lit> {
+    /// Converts an arbitrary token into meta item literal.
+    pub fn from_token(token: &Token) -> Option<MetaItemLit> {
         token::Lit::from_token(token)
-            .and_then(|token_lit| Lit::from_token_lit(token_lit, token.span).ok())
+            .and_then(|token_lit| MetaItemLit::from_token_lit(token_lit, token.span).ok())
     }
 
-    /// Attempts to recover an AST literal from semantic literal.
+    /// Attempts to create a meta item literal from a `LitKind`.
     /// 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 from_lit_kind(kind: LitKind, span: Span) -> Lit {
-        Lit { token_lit: kind.to_token_lit(), kind, span }
+    pub fn from_lit_kind(kind: LitKind, span: Span) -> MetaItemLit {
+        MetaItemLit { token_lit: kind.to_token_lit(), kind, span }
     }
 
-    /// Recovers an AST literal from a string of bytes produced by `include_bytes!`.
-    /// This requires ASCII-escaping the string, which can result in poor performance
-    /// for very large strings of bytes.
-    pub fn from_included_bytes(bytes: &Lrc<[u8]>, span: Span) -> Lit {
-        Self::from_lit_kind(LitKind::ByteStr(bytes.clone()), span)
-    }
-
-    /// Losslessly convert an AST literal into a token.
+    /// Losslessly convert a meta item literal into a token.
     pub fn to_token(&self) -> Token {
         let kind = match self.token_lit.kind {
             token::Bool => token::Ident(self.token_lit.symbol, false),

compiler/rustc_ast_lowering/src/lib.rs

@@ -948,17 +948,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             AttrArgs::Eq(eq_span, AttrArgsEq::Ast(expr)) => {
                 // In valid code the value always ends up as a single literal. Otherwise, a dummy
                 // literal suffices because the error is handled elsewhere.
-                let lit = if let ExprKind::Lit(token_lit) = expr.kind {
-                    match Lit::from_token_lit(token_lit, expr.span) {
-                        Ok(lit) => lit,
-                        Err(_err) => Lit {
-                            token_lit: token::Lit::new(token::LitKind::Err, kw::Empty, None),
-                            kind: LitKind::Err,
-                            span: DUMMY_SP,
-                        },
-                    }
+                let lit = if let ExprKind::Lit(token_lit) = expr.kind
+                    && let Ok(lit) = MetaItemLit::from_token_lit(token_lit, expr.span)
+                {
+                    lit
                 } else {
-                    Lit {
+                    MetaItemLit {
                         token_lit: token::Lit::new(token::LitKind::Err, kw::Empty, None),
                         kind: LitKind::Err,
                         span: DUMMY_SP,

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -371,7 +371,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         }
     }
 
-    fn print_literal(&mut self, lit: &ast::Lit) {
+    fn print_meta_item_lit(&mut self, lit: &ast::MetaItemLit) {
         self.print_token_literal(lit.token_lit, lit.span)
     }
 
@@ -488,7 +488,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                 self.print_path(&item.path, false, 0);
                 self.space();
                 self.word_space("=");
-                let token_str = self.literal_to_string(lit);
+                let token_str = self.meta_item_lit_to_string(lit);
                 self.word(token_str);
             }
         }
@@ -498,7 +498,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     fn print_meta_list_item(&mut self, item: &ast::NestedMetaItem) {
         match item {
             ast::NestedMetaItem::MetaItem(ref mi) => self.print_meta_item(mi),
-            ast::NestedMetaItem::Literal(ref lit) => self.print_literal(lit),
+            ast::NestedMetaItem::Lit(ref lit) => self.print_meta_item_lit(lit),
         }
     }
 
@@ -510,7 +510,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                 self.print_path(&item.path, false, 0);
                 self.space();
                 self.word_space("=");
-                self.print_literal(value);
+                self.print_meta_item_lit(value);
             }
             ast::MetaItemKind::List(ref items) => {
                 self.print_path(&item.path, false, 0);
@@ -825,8 +825,8 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         Self::to_string(|s| s.print_expr(e))
     }
 
-    fn literal_to_string(&self, lit: &ast::Lit) -> String {
-        Self::to_string(|s| s.print_literal(lit))
+    fn meta_item_lit_to_string(&self, lit: &ast::MetaItemLit) -> String {
+        Self::to_string(|s| s.print_meta_item_lit(lit))
     }
 
     fn tt_to_string(&self, tt: &TokenTree) -> String {

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

@@ -328,8 +328,8 @@ impl<'a> State<'a> {
                 self.print_token_literal(token_lit, expr.span);
             }
             ast::ExprKind::IncludedBytes(ref bytes) => {
-                let lit = ast::Lit::from_included_bytes(bytes, expr.span);
-                self.print_literal(&lit)
+                let lit = ast::LitKind::ByteStr(bytes.clone()).to_token_lit();
+                self.print_token_literal(lit, expr.span)
             }
             ast::ExprKind::Cast(ref expr, ref ty) => {
                 let prec = AssocOp::As.precedence() as i8;

compiler/rustc_attr/src/builtin.rs

@@ -1,7 +1,7 @@
 //! Parsing and validation of builtin attributes
 
 use rustc_ast as ast;
-use rustc_ast::{Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem, NodeId};
+use rustc_ast::{Attribute, LitKind, MetaItem, MetaItemKind, MetaItemLit, NestedMetaItem, NodeId};
 use rustc_ast_pretty::pprust;
 use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg};
 use rustc_macros::HashStable_Generic;
@@ -486,7 +486,7 @@ where
                                     continue 'outer;
                                 }
                             },
-                            NestedMetaItem::Literal(lit) => {
+                            NestedMetaItem::Lit(lit) => {
                                 handle_errors(
                                     &sess.parse_sess,
                                     lit.span,
@@ -658,11 +658,11 @@ pub fn eval_condition(
         ast::MetaItemKind::List(ref mis) if cfg.name_or_empty() == sym::version => {
             try_gate_cfg(sym::version, cfg.span, sess, features);
             let (min_version, span) = match &mis[..] {
-                [NestedMetaItem::Literal(Lit { kind: LitKind::Str(sym, ..), span, .. })] => {
+                [NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => {
                     (sym, span)
                 }
                 [
-                    NestedMetaItem::Literal(Lit { span, .. })
+                    NestedMetaItem::Lit(MetaItemLit { span, .. })
                     | NestedMetaItem::MetaItem(MetaItem { span, .. }),
                 ] => {
                     sess.emit_err(session_diagnostics::ExpectedVersionLiteral { span: *span });
@@ -899,7 +899,7 @@ where
                                 continue 'outer;
                             }
                         },
-                        NestedMetaItem::Literal(lit) => {
+                        NestedMetaItem::Lit(lit) => {
                             handle_errors(
                                 &sess.parse_sess,
                                 lit.span,