Move format_args!() into AST (and expand it during AST lowering)

Cargo.lock

@@ -3699,6 +3699,7 @@ name = "rustc_ast_pretty"
 version = "0.0.0"
 dependencies = [
  "rustc_ast",
+ "rustc_parse_format",
  "rustc_span",
 ]
 

compiler/rustc_ast/src/ast.rs

@@ -18,6 +18,7 @@
 //! - [`Attribute`]: Metadata associated with item.
 //! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
 
+pub use crate::format::*;
 pub use crate::util::parser::ExprPrecedence;
 pub use GenericArgs::*;
 pub use UnsafeSource::*;
@@ -1269,6 +1270,7 @@ impl Expr {
             ExprKind::Try(..) => ExprPrecedence::Try,
             ExprKind::Yield(..) => ExprPrecedence::Yield,
             ExprKind::Yeet(..) => ExprPrecedence::Yeet,
+            ExprKind::FormatArgs(..) => ExprPrecedence::FormatArgs,
             ExprKind::Err => ExprPrecedence::Err,
         }
     }
@@ -1498,6 +1500,9 @@ pub enum ExprKind {
     /// with a `ByteStr` literal.
     IncludedBytes(Lrc<[u8]>),
 
+    /// A `format_args!()` expression.
+    FormatArgs(P<FormatArgs>),
+
     /// Placeholder for an expression that wasn't syntactically well formed in some way.
     Err,
 }

compiler/rustc_builtin_macros/src/format/ast.rs → compiler/rustc_ast/src/format.rs

@@ -1,5 +1,5 @@
-use rustc_ast::ptr::P;
-use rustc_ast::Expr;
+use crate::ptr::P;
+use crate::Expr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::Span;
@@ -39,7 +39,7 @@ use rustc_span::Span;
 /// Basically the "AST" for a complete `format_args!()`.
 ///
 /// E.g., `format_args!("hello {name}");`.
-#[derive(Clone, Debug)]
+#[derive(Clone, Encodable, Decodable, Debug)]
 pub struct FormatArgs {
     pub span: Span,
     pub template: Vec<FormatArgsPiece>,
@@ -49,7 +49,7 @@ pub struct FormatArgs {
 /// A piece of a format template string.
 ///
 /// E.g. "hello" or "{name}".
-#[derive(Clone, Debug)]
+#[derive(Clone, Encodable, Decodable, Debug)]
 pub enum FormatArgsPiece {
     Literal(Symbol),
     Placeholder(FormatPlaceholder),
@@ -59,7 +59,7 @@ pub enum FormatArgsPiece {
 ///
 /// E.g. `1, 2, name="ferris", n=3`,
 /// but also implicit captured arguments like `x` in `format_args!("{x}")`.
-#[derive(Clone, Debug)]
+#[derive(Clone, Encodable, Decodable, Debug)]
 pub struct FormatArguments {
     arguments: Vec<FormatArgument>,
     num_unnamed_args: usize,
@@ -121,18 +121,22 @@ impl FormatArguments {
         &self.arguments[..self.num_explicit_args]
     }
 
-    pub fn into_vec(self) -> Vec<FormatArgument> {
-        self.arguments
+    pub fn all_args(&self) -> &[FormatArgument] {
+        &self.arguments[..]
+    }
+
+    pub fn all_args_mut(&mut self) -> &mut [FormatArgument] {
+        &mut self.arguments[..]
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Encodable, Decodable, Debug)]
 pub struct FormatArgument {
     pub kind: FormatArgumentKind,
     pub expr: P<Expr>,
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Encodable, Decodable, Debug)]
 pub enum FormatArgumentKind {
     /// `format_args(…, arg)`
     Normal,
@@ -152,7 +156,7 @@ impl FormatArgumentKind {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub struct FormatPlaceholder {
     /// Index into [`FormatArgs::arguments`].
     pub argument: FormatArgPosition,
@@ -164,7 +168,7 @@ pub struct FormatPlaceholder {
     pub format_options: FormatOptions,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub struct FormatArgPosition {
     /// Which argument this position refers to (Ok),
     /// or would've referred to if it existed (Err).
@@ -175,7 +179,7 @@ pub struct FormatArgPosition {
     pub span: Option<Span>,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub enum FormatArgPositionKind {
     /// `{}` or `{:.*}`
     Implicit,
@@ -185,7 +189,7 @@ pub enum FormatArgPositionKind {
     Named,
 }
 
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
+#[derive(Copy, Clone, Encodable, Decodable, Debug, PartialEq, Eq, Hash)]
 pub enum FormatTrait {
     /// `{}`
     Display,
@@ -207,7 +211,7 @@ pub enum FormatTrait {
     UpperHex,
 }
 
-#[derive(Clone, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Encodable, Decodable, Default, Debug, PartialEq, Eq)]
 pub struct FormatOptions {
     /// The width. E.g. `{:5}` or `{:width$}`.
     pub width: Option<FormatCount>,
@@ -221,7 +225,7 @@ pub struct FormatOptions {
     pub flags: u32,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub enum FormatAlignment {
     /// `{:<}`
     Left,
@@ -231,7 +235,7 @@ pub enum FormatAlignment {
     Center,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub enum FormatCount {
     /// `{:5}` or `{:.5}`
     Literal(usize),

compiler/rustc_ast/src/lib.rs

@@ -42,6 +42,7 @@ pub mod ast_traits;
 pub mod attr;
 pub mod entry;
 pub mod expand;
+pub mod format;
 pub mod mut_visit;
 pub mod node_id;
 pub mod ptr;
@@ -51,6 +52,7 @@ pub mod visit;
 
 pub use self::ast::*;
 pub use self::ast_traits::{AstDeref, AstNodeWrapper, HasAttrs, HasNodeId, HasSpan, HasTokens};
+pub use self::format::*;
 
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 

compiler/rustc_ast/src/mut_visit.rs

@@ -297,6 +297,10 @@ pub trait MutVisitor: Sized {
     fn visit_inline_asm_sym(&mut self, sym: &mut InlineAsmSym) {
         noop_visit_inline_asm_sym(sym, self)
     }
+
+    fn visit_format_args(&mut self, fmt: &mut FormatArgs) {
+        noop_visit_format_args(fmt, self)
+    }
 }
 
 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
@@ -1284,6 +1288,15 @@ pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
     vis.visit_path(path);
 }
 
+pub fn noop_visit_format_args<T: MutVisitor>(fmt: &mut FormatArgs, vis: &mut T) {
+    for arg in fmt.arguments.all_args_mut() {
+        if let FormatArgumentKind::Named(name) = &mut arg.kind {
+            vis.visit_ident(name);
+        }
+        vis.visit_expr(&mut arg.expr);
+    }
+}
+
 pub fn noop_visit_expr<T: MutVisitor>(
     Expr { kind, id, span, attrs, tokens }: &mut Expr,
     vis: &mut T,
@@ -1423,6 +1436,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             visit_opt(expr, |expr| vis.visit_expr(expr));
         }
         ExprKind::InlineAsm(asm) => vis.visit_inline_asm(asm),
+        ExprKind::FormatArgs(fmt) => vis.visit_format_args(fmt),
         ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
         ExprKind::Struct(se) => {
             let StructExpr { qself, path, fields, rest } = se.deref_mut();

compiler/rustc_ast/src/util/parser.rs

@@ -271,6 +271,7 @@ pub enum ExprPrecedence {
     Try,
     InlineAsm,
     Mac,
+    FormatArgs,
 
     Array,
     Repeat,
@@ -335,7 +336,8 @@ impl ExprPrecedence {
             | ExprPrecedence::Index
             | ExprPrecedence::Try
             | ExprPrecedence::InlineAsm
-            | ExprPrecedence::Mac => PREC_POSTFIX,
+            | ExprPrecedence::Mac
+            | ExprPrecedence::FormatArgs => PREC_POSTFIX,
 
             // Never need parens
             ExprPrecedence::Array

compiler/rustc_ast/src/visit.rs

@@ -242,6 +242,9 @@ pub trait Visitor<'ast>: Sized {
     fn visit_inline_asm(&mut self, asm: &'ast InlineAsm) {
         walk_inline_asm(self, asm)
     }
+    fn visit_format_args(&mut self, fmt: &'ast FormatArgs) {
+        walk_format_args(self, fmt)
+    }
     fn visit_inline_asm_sym(&mut self, sym: &'ast InlineAsmSym) {
         walk_inline_asm_sym(self, sym)
     }
@@ -756,6 +759,15 @@ pub fn walk_inline_asm_sym<'a, V: Visitor<'a>>(visitor: &mut V, sym: &'a InlineA
     visitor.visit_path(&sym.path, sym.id);
 }
 
+pub fn walk_format_args<'a, V: Visitor<'a>>(visitor: &mut V, fmt: &'a FormatArgs) {
+    for arg in fmt.arguments.all_args() {
+        if let FormatArgumentKind::Named(name) = arg.kind {
+            visitor.visit_ident(name);
+        }
+        visitor.visit_expr(&arg.expr);
+    }
+}
+
 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
     walk_list!(visitor, visit_attribute, expression.attrs.iter());
 
@@ -895,6 +907,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
         ExprKind::MacCall(mac) => visitor.visit_mac_call(mac),
         ExprKind::Paren(subexpression) => visitor.visit_expr(subexpression),
         ExprKind::InlineAsm(asm) => visitor.visit_inline_asm(asm),
+        ExprKind::FormatArgs(f) => visitor.visit_format_args(f),
         ExprKind::Yield(optional_expression) => {
             walk_list!(visitor, visit_expr, optional_expression);
         }