Inline ExprPrecedence::order into Expr::precedence

Author: dtolnay

compiler/rustc_ast/src/ast.rs

@@ -39,7 +39,9 @@ pub use crate::format::*;
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Delimiter};
 use crate::tokenstream::{DelimSpan, LazyAttrTokenStream, TokenStream};
-pub use crate::util::parser::ExprPrecedence;
+use crate::util::parser::{
+    AssocOp, PREC_CLOSURE, PREC_JUMP, PREC_PREFIX, PREC_RANGE, PREC_UNAMBIGUOUS,
+};
 
 /// A "Label" is an identifier of some point in sources,
 /// e.g. in the following code:
@@ -1319,53 +1321,71 @@ impl Expr {
         Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
     }
 
-    pub fn precedence(&self) -> ExprPrecedence {
+    pub fn precedence(&self) -> i8 {
         match self.kind {
-            ExprKind::Array(_) => ExprPrecedence::Array,
-            ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
-            ExprKind::Call(..) => ExprPrecedence::Call,
-            ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
-            ExprKind::Tup(_) => ExprPrecedence::Tup,
-            ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
-            ExprKind::Unary(..) => ExprPrecedence::Unary,
-            ExprKind::Lit(_) | ExprKind::IncludedBytes(..) => ExprPrecedence::Lit,
-            ExprKind::Cast(..) => ExprPrecedence::Cast,
-            ExprKind::Let(..) => ExprPrecedence::Let,
-            ExprKind::If(..) => ExprPrecedence::If,
-            ExprKind::While(..) => ExprPrecedence::While,
-            ExprKind::ForLoop { .. } => ExprPrecedence::ForLoop,
-            ExprKind::Loop(..) => ExprPrecedence::Loop,
-            ExprKind::Match(_, _, MatchKind::Prefix) => ExprPrecedence::Match,
-            ExprKind::Match(_, _, MatchKind::Postfix) => ExprPrecedence::PostfixMatch,
-            ExprKind::Closure(..) => ExprPrecedence::Closure,
-            ExprKind::Block(..) => ExprPrecedence::Block,
-            ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
-            ExprKind::Gen(..) => ExprPrecedence::Gen,
-            ExprKind::Await(..) => ExprPrecedence::Await,
-            ExprKind::Assign(..) => ExprPrecedence::Assign,
-            ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
-            ExprKind::Field(..) => ExprPrecedence::Field,
-            ExprKind::Index(..) => ExprPrecedence::Index,
-            ExprKind::Range(..) => ExprPrecedence::Range,
-            ExprKind::Underscore => ExprPrecedence::Path,
-            ExprKind::Path(..) => ExprPrecedence::Path,
-            ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
-            ExprKind::Break(..) => ExprPrecedence::Break,
-            ExprKind::Continue(..) => ExprPrecedence::Continue,
-            ExprKind::Ret(..) => ExprPrecedence::Ret,
-            ExprKind::Struct(..) => ExprPrecedence::Struct,
-            ExprKind::Repeat(..) => ExprPrecedence::Repeat,
-            ExprKind::Paren(..) => ExprPrecedence::Paren,
-            ExprKind::Try(..) => ExprPrecedence::Try,
-            ExprKind::Yield(..) => ExprPrecedence::Yield,
-            ExprKind::Yeet(..) => ExprPrecedence::Yeet,
-            ExprKind::Become(..) => ExprPrecedence::Become,
-            ExprKind::InlineAsm(..)
-            | ExprKind::Type(..)
-            | ExprKind::OffsetOf(..)
+            ExprKind::Closure(..) => PREC_CLOSURE,
+
+            ExprKind::Break(..)
+            | ExprKind::Continue(..)
+            | ExprKind::Ret(..)
+            | ExprKind::Yield(..)
+            | ExprKind::Yeet(..)
+            | ExprKind::Become(..) => PREC_JUMP,
+
+            // `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
+            // parse, instead of parsing as `(x .. x) = x`. Giving `Range` a lower precedence
+            // ensures that `pprust` will add parentheses in the right places to get the desired
+            // parse.
+            ExprKind::Range(..) => PREC_RANGE,
+
+            // Binop-like expr kinds, handled by `AssocOp`.
+            ExprKind::Binary(op, ..) => AssocOp::from_ast_binop(op.node).precedence() as i8,
+            ExprKind::Cast(..) => AssocOp::As.precedence() as i8,
+
+            ExprKind::Assign(..) |
+            ExprKind::AssignOp(..) => AssocOp::Assign.precedence() as i8,
+
+            // Unary, prefix
+            ExprKind::AddrOf(..)
+            // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
+            // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
+            // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
+            // but we need to print `(let _ = a) < b` as-is with parens.
+            | ExprKind::Let(..)
+            | ExprKind::Unary(..) => PREC_PREFIX,
+
+            // Never need parens
+            ExprKind::Array(_)
+            | ExprKind::Await(..)
+            | ExprKind::Block(..)
+            | ExprKind::Call(..)
+            | ExprKind::ConstBlock(_)
+            | ExprKind::Field(..)
+            | ExprKind::ForLoop { .. }
             | ExprKind::FormatArgs(..)
-            | ExprKind::MacCall(..) => ExprPrecedence::Mac,
-            ExprKind::Err(_) | ExprKind::Dummy => ExprPrecedence::Err,
+            | ExprKind::Gen(..)
+            | ExprKind::If(..)
+            | ExprKind::IncludedBytes(..)
+            | ExprKind::Index(..)
+            | ExprKind::InlineAsm(..)
+            | ExprKind::Lit(_)
+            | ExprKind::Loop(..)
+            | ExprKind::MacCall(..)
+            | ExprKind::Match(..)
+            | ExprKind::MethodCall(..)
+            | ExprKind::OffsetOf(..)
+            | ExprKind::Paren(..)
+            | ExprKind::Path(..)
+            | ExprKind::Repeat(..)
+            | ExprKind::Struct(..)
+            | ExprKind::Try(..)
+            | ExprKind::TryBlock(..)
+            | ExprKind::Tup(_)
+            | ExprKind::Type(..)
+            | ExprKind::Underscore
+            | ExprKind::While(..)
+            | ExprKind::Err(_)
+            | ExprKind::Dummy => PREC_UNAMBIGUOUS,
         }
     }
 

compiler/rustc_ast/src/util/parser.rs

@@ -237,121 +237,6 @@ pub const PREC_PREFIX: i8 = 50;
 pub const PREC_UNAMBIGUOUS: i8 = 60;
 pub const PREC_FORCE_PAREN: i8 = 100;
 
-#[derive(Debug, Clone, Copy)]
-pub enum ExprPrecedence {
-    Closure,
-    Break,
-    Continue,
-    Ret,
-    Yield,
-    Yeet,
-    Become,
-
-    Range,
-
-    Binary(BinOpKind),
-
-    Cast,
-
-    Assign,
-    AssignOp,
-
-    AddrOf,
-    Let,
-    Unary,
-
-    Call,
-    MethodCall,
-    Field,
-    Index,
-    Try,
-    Mac,
-
-    Array,
-    Repeat,
-    Tup,
-    Lit,
-    Path,
-    Paren,
-    If,
-    While,
-    ForLoop,
-    Loop,
-    Match,
-    PostfixMatch,
-    ConstBlock,
-    Block,
-    TryBlock,
-    Struct,
-    Gen,
-    Await,
-    Err,
-}
-
-impl ExprPrecedence {
-    pub fn order(self) -> i8 {
-        match self {
-            ExprPrecedence::Closure => PREC_CLOSURE,
-
-            ExprPrecedence::Break
-            | ExprPrecedence::Continue
-            | ExprPrecedence::Ret
-            | ExprPrecedence::Yield
-            | ExprPrecedence::Yeet
-            | ExprPrecedence::Become => PREC_JUMP,
-
-            // `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
-            // parse, instead of parsing as `(x .. x) = x`. Giving `Range` a lower precedence
-            // ensures that `pprust` will add parentheses in the right places to get the desired
-            // parse.
-            ExprPrecedence::Range => PREC_RANGE,
-
-            // Binop-like expr kinds, handled by `AssocOp`.
-            ExprPrecedence::Binary(op) => AssocOp::from_ast_binop(op).precedence() as i8,
-            ExprPrecedence::Cast => AssocOp::As.precedence() as i8,
-
-            ExprPrecedence::Assign |
-            ExprPrecedence::AssignOp => AssocOp::Assign.precedence() as i8,
-
-            // Unary, prefix
-            ExprPrecedence::AddrOf
-            // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
-            // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
-            // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
-            // but we need to print `(let _ = a) < b` as-is with parens.
-            | ExprPrecedence::Let
-            | ExprPrecedence::Unary => PREC_PREFIX,
-
-            // Never need parens
-            ExprPrecedence::Array
-            | ExprPrecedence::Await
-            | ExprPrecedence::Block
-            | ExprPrecedence::Call
-            | ExprPrecedence::ConstBlock
-            | ExprPrecedence::Field
-            | ExprPrecedence::ForLoop
-            | ExprPrecedence::Gen
-            | ExprPrecedence::If
-            | ExprPrecedence::Index
-            | ExprPrecedence::Lit
-            | ExprPrecedence::Loop
-            | ExprPrecedence::Mac
-            | ExprPrecedence::Match
-            | ExprPrecedence::MethodCall
-            | ExprPrecedence::Paren
-            | ExprPrecedence::Path
-            | ExprPrecedence::PostfixMatch
-            | ExprPrecedence::Repeat
-            | ExprPrecedence::Struct
-            | ExprPrecedence::Try
-            | ExprPrecedence::TryBlock
-            | ExprPrecedence::Tup
-            | ExprPrecedence::While
-            | ExprPrecedence::Err => PREC_UNAMBIGUOUS,
-        }
-    }
-}
-
 /// In `let p = e`, operators with precedence `<=` this one requires parentheses in `e`.
 pub fn prec_let_scrutinee_needs_par() -> usize {
     AssocOp::LAnd.precedence()

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

@@ -59,7 +59,7 @@ impl<'a> State<'a> {
     }
 
     fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8, fixup: FixupContext) {
-        self.print_expr_cond_paren(expr, expr.precedence().order() < prec, fixup);
+        self.print_expr_cond_paren(expr, expr.precedence() < prec, fixup);
     }
 
     /// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
@@ -615,7 +615,7 @@ impl<'a> State<'a> {
                         expr,
                         // Parenthesize if required by precedence, or in the
                         // case of `break 'inner: loop { break 'inner 1 } + 1`
-                        expr.precedence().order() < parser::PREC_JUMP
+                        expr.precedence() < parser::PREC_JUMP
                             || (opt_label.is_none() && classify::leading_labeled_expr(expr)),
                         fixup.subsequent_subexpression(),
                     );

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

@@ -191,6 +191,6 @@ impl FixupContext {
     ///     "let chain".
     pub(crate) fn needs_par_as_let_scrutinee(self, expr: &Expr) -> bool {
         self.parenthesize_exterior_struct_lit && parser::contains_exterior_struct_lit(expr)
-            || parser::needs_par_as_let_scrutinee(expr.precedence().order())
+            || parser::needs_par_as_let_scrutinee(expr.precedence())
     }
 }

compiler/rustc_hir/src/hir.rs

@@ -1,7 +1,7 @@
 use std::fmt;
 
 use rustc_abi::ExternAbi;
-use rustc_ast::util::parser::ExprPrecedence;
+use rustc_ast::util::parser::{AssocOp, PREC_CLOSURE, PREC_JUMP, PREC_PREFIX, PREC_UNAMBIGUOUS};
 use rustc_ast::{
     self as ast, Attribute, FloatTy, InlineAsmOptions, InlineAsmTemplatePiece, IntTy, Label,
     LitKind, TraitObjectSyntax, UintTy,
@@ -1719,41 +1719,54 @@ pub struct Expr<'hir> {
 }
 
 impl Expr<'_> {
-    pub fn precedence(&self) -> ExprPrecedence {
+    pub fn precedence(&self) -> i8 {
         match self.kind {
-            ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
-            ExprKind::Array(_) => ExprPrecedence::Array,
-            ExprKind::Call(..) => ExprPrecedence::Call,
-            ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
-            ExprKind::Tup(_) => ExprPrecedence::Tup,
-            ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
-            ExprKind::Unary(..) => ExprPrecedence::Unary,
-            ExprKind::Lit(_) => ExprPrecedence::Lit,
-            ExprKind::Cast(..) => ExprPrecedence::Cast,
+            ExprKind::Closure { .. } => PREC_CLOSURE,
+
+            ExprKind::Break(..)
+            | ExprKind::Continue(..)
+            | ExprKind::Ret(..)
+            | ExprKind::Yield(..)
+            | ExprKind::Become(..) => PREC_JUMP,
+
+            // Binop-like expr kinds, handled by `AssocOp`.
+            ExprKind::Binary(op, ..) => AssocOp::from_ast_binop(op.node).precedence() as i8,
+            ExprKind::Cast(..) => AssocOp::As.precedence() as i8,
+
+            ExprKind::Assign(..) |
+            ExprKind::AssignOp(..) => AssocOp::Assign.precedence() as i8,
+
+            // Unary, prefix
+            ExprKind::AddrOf(..)
+            // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
+            // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
+            // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
+            // but we need to print `(let _ = a) < b` as-is with parens.
+            | ExprKind::Let(..)
+            | ExprKind::Unary(..) => PREC_PREFIX,
+
+            // Never need parens
+            ExprKind::Array(_)
+            | ExprKind::Block(..)
+            | ExprKind::Call(..)
+            | ExprKind::ConstBlock(_)
+            | ExprKind::Field(..)
+            | ExprKind::If(..)
+            | ExprKind::Index(..)
+            | ExprKind::InlineAsm(..)
+            | ExprKind::Lit(_)
+            | ExprKind::Loop(..)
+            | ExprKind::Match(..)
+            | ExprKind::MethodCall(..)
+            | ExprKind::OffsetOf(..)
+            | ExprKind::Path(..)
+            | ExprKind::Repeat(..)
+            | ExprKind::Struct(..)
+            | ExprKind::Tup(_)
+            | ExprKind::Type(..)
+            | ExprKind::Err(_) => PREC_UNAMBIGUOUS,
+
             ExprKind::DropTemps(ref expr, ..) => expr.precedence(),
-            ExprKind::If(..) => ExprPrecedence::If,
-            ExprKind::Let(..) => ExprPrecedence::Let,
-            ExprKind::Loop(..) => ExprPrecedence::Loop,
-            ExprKind::Match(..) => ExprPrecedence::Match,
-            ExprKind::Closure { .. } => ExprPrecedence::Closure,
-            ExprKind::Block(..) => ExprPrecedence::Block,
-            ExprKind::Assign(..) => ExprPrecedence::Assign,
-            ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
-            ExprKind::Field(..) => ExprPrecedence::Field,
-            ExprKind::Index(..) => ExprPrecedence::Index,
-            ExprKind::Path(..) => ExprPrecedence::Path,
-            ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
-            ExprKind::Break(..) => ExprPrecedence::Break,
-            ExprKind::Continue(..) => ExprPrecedence::Continue,
-            ExprKind::Ret(..) => ExprPrecedence::Ret,
-            ExprKind::Become(..) => ExprPrecedence::Become,
-            ExprKind::Struct(..) => ExprPrecedence::Struct,
-            ExprKind::Repeat(..) => ExprPrecedence::Repeat,
-            ExprKind::Yield(..) => ExprPrecedence::Yield,
-            ExprKind::Type(..) | ExprKind::InlineAsm(..) | ExprKind::OffsetOf(..) => {
-                ExprPrecedence::Mac
-            }
-            ExprKind::Err(_) => ExprPrecedence::Err,
         }
     }
 

compiler/rustc_hir_pretty/src/lib.rs

@@ -1015,7 +1015,7 @@ impl<'a> State<'a> {
     }
 
     fn print_expr_maybe_paren(&mut self, expr: &hir::Expr<'_>, prec: i8) {
-        self.print_expr_cond_paren(expr, expr.precedence().order() < prec)
+        self.print_expr_cond_paren(expr, expr.precedence() < prec)
     }
 
     /// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
@@ -1049,7 +1049,7 @@ impl<'a> State<'a> {
         }
         self.space();
         self.word_space("=");
-        let npals = || parser::needs_par_as_let_scrutinee(init.precedence().order());
+        let npals = || parser::needs_par_as_let_scrutinee(init.precedence());
         self.print_expr_cond_paren(init, Self::cond_needs_par(init) || npals())
     }
 

compiler/rustc_hir_typeck/src/callee.rs

@@ -606,7 +606,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             };
 
             if let Ok(rest_snippet) = rest_snippet {
-                let sugg = if callee_expr.precedence().order() >= PREC_UNAMBIGUOUS {
+                let sugg = if callee_expr.precedence() >= PREC_UNAMBIGUOUS {
                     vec![
                         (up_to_rcvr_span, "".to_string()),
                         (rest_span, format!(".{}({rest_snippet}", segment.ident)),