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Rename the 2 unambiguous precedence levels to PREC_UNAMBIGUOUS
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@dtolnay
dtolnay committed Jun 24, 2024
1 parent 8cfd4b1 commit 273447c
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Showing 8 changed files with 44 additions and 47 deletions.
45 changes: 21 additions & 24 deletions compiler/rustc_ast/src/util/parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -233,8 +233,7 @@ pub const PREC_JUMP: i8 = -30;
pub const PREC_RANGE: i8 = -10;
// The range 2..=14 is reserved for AssocOp binary operator precedences.
pub const PREC_PREFIX: i8 = 50;
pub const PREC_POSTFIX: i8 = 60;
pub const PREC_PAREN: i8 = 60;
pub const PREC_UNAMBIGUOUS: i8 = 60;
pub const PREC_FORCE_PAREN: i8 = 100;

#[derive(Debug, Clone, Copy)]
Expand Down Expand Up @@ -325,37 +324,35 @@ impl ExprPrecedence {
| ExprPrecedence::Let
| ExprPrecedence::Unary => PREC_PREFIX,

// Unary, postfix
ExprPrecedence::Await
// Never need parens
ExprPrecedence::Array
| ExprPrecedence::Await
| ExprPrecedence::Block
| ExprPrecedence::Call
| ExprPrecedence::MethodCall
| ExprPrecedence::ConstBlock
| ExprPrecedence::Field
| ExprPrecedence::ForLoop
| ExprPrecedence::FormatArgs
| ExprPrecedence::Gen
| ExprPrecedence::If
| ExprPrecedence::Index
| ExprPrecedence::Try
| ExprPrecedence::InlineAsm
| ExprPrecedence::Lit
| ExprPrecedence::Loop
| ExprPrecedence::Mac
| ExprPrecedence::FormatArgs
| ExprPrecedence::Match
| ExprPrecedence::MethodCall
| ExprPrecedence::OffsetOf
| ExprPrecedence::PostfixMatch => PREC_POSTFIX,

// Never need parens
ExprPrecedence::Array
| ExprPrecedence::Paren
| ExprPrecedence::Path
| ExprPrecedence::PostfixMatch
| ExprPrecedence::Repeat
| ExprPrecedence::Struct
| ExprPrecedence::Try
| ExprPrecedence::TryBlock
| ExprPrecedence::Tup
| ExprPrecedence::Lit
| ExprPrecedence::Path
| ExprPrecedence::Paren
| ExprPrecedence::If
| ExprPrecedence::While
| ExprPrecedence::ForLoop
| ExprPrecedence::Loop
| ExprPrecedence::Match
| ExprPrecedence::ConstBlock
| ExprPrecedence::Block
| ExprPrecedence::TryBlock
| ExprPrecedence::Gen
| ExprPrecedence::Struct
| ExprPrecedence::Err => PREC_PAREN,
| ExprPrecedence::Err => PREC_UNAMBIGUOUS,
}
}
}
Expand Down
14 changes: 7 additions & 7 deletions compiler/rustc_ast_pretty/src/pprust/state/expr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -217,7 +217,7 @@ impl<'a> State<'a> {
fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>], fixup: FixupContext) {
let prec = match func.kind {
ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
_ => parser::PREC_POSTFIX,
_ => parser::PREC_UNAMBIGUOUS,
};

// Independent of parenthesization related to precedence, we must
Expand Down Expand Up @@ -257,7 +257,7 @@ impl<'a> State<'a> {
// boundaries, `$receiver.method()` can be parsed back as a statement
// containing an expression if and only if `$receiver` can be parsed as
// a statement containing an expression.
self.print_expr_maybe_paren(receiver, parser::PREC_POSTFIX, fixup);
self.print_expr_maybe_paren(receiver, parser::PREC_UNAMBIGUOUS, fixup);

self.word(".");
self.print_ident(segment.ident);
Expand Down Expand Up @@ -489,7 +489,7 @@ impl<'a> State<'a> {
self.space();
}
MatchKind::Postfix => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX, fixup);
self.print_expr_maybe_paren(expr, parser::PREC_UNAMBIGUOUS, fixup);
self.word_nbsp(".match");
}
}
Expand Down Expand Up @@ -549,7 +549,7 @@ impl<'a> State<'a> {
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Await(expr, _) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX, fixup);
self.print_expr_maybe_paren(expr, parser::PREC_UNAMBIGUOUS, fixup);
self.word(".await");
}
ast::ExprKind::Assign(lhs, rhs, _) => {
Expand All @@ -568,14 +568,14 @@ impl<'a> State<'a> {
self.print_expr_maybe_paren(rhs, prec, fixup.subsequent_subexpression());
}
ast::ExprKind::Field(expr, ident) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX, fixup);
self.print_expr_maybe_paren(expr, parser::PREC_UNAMBIGUOUS, fixup);
self.word(".");
self.print_ident(*ident);
}
ast::ExprKind::Index(expr, index, _) => {
self.print_expr_maybe_paren(
expr,
parser::PREC_POSTFIX,
parser::PREC_UNAMBIGUOUS,
fixup.leftmost_subexpression(),
);
self.word("[");
Expand Down Expand Up @@ -713,7 +713,7 @@ impl<'a> State<'a> {
}
}
ast::ExprKind::Try(e) => {
self.print_expr_maybe_paren(e, parser::PREC_POSTFIX, fixup);
self.print_expr_maybe_paren(e, parser::PREC_UNAMBIGUOUS, fixup);
self.word("?")
}
ast::ExprKind::TryBlock(blk) => {
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_hir_pretty/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1120,7 +1120,7 @@ impl<'a> State<'a> {
fn print_expr_call(&mut self, func: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let prec = match func.kind {
hir::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
_ => parser::PREC_POSTFIX,
_ => parser::PREC_UNAMBIGUOUS,
};

self.print_expr_maybe_paren(func, prec);
Expand All @@ -1134,7 +1134,7 @@ impl<'a> State<'a> {
args: &[hir::Expr<'_>],
) {
let base_args = args;
self.print_expr_maybe_paren(receiver, parser::PREC_POSTFIX);
self.print_expr_maybe_paren(receiver, parser::PREC_UNAMBIGUOUS);
self.word(".");
self.print_ident(segment.ident);

Expand Down Expand Up @@ -1478,12 +1478,12 @@ impl<'a> State<'a> {
self.print_expr_maybe_paren(rhs, prec);
}
hir::ExprKind::Field(expr, ident) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.print_expr_maybe_paren(expr, parser::PREC_UNAMBIGUOUS);
self.word(".");
self.print_ident(ident);
}
hir::ExprKind::Index(expr, index, _) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.print_expr_maybe_paren(expr, parser::PREC_UNAMBIGUOUS);
self.word("[");
self.print_expr(index);
self.word("]");
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_hir_typeck/src/callee.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use super::method::MethodCallee;
use super::{Expectation, FnCtxt, TupleArgumentsFlag};

use crate::errors;
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_ast::util::parser::PREC_UNAMBIGUOUS;
use rustc_errors::{Applicability, Diag, ErrorGuaranteed, StashKey};
use rustc_hir::def::{self, CtorKind, Namespace, Res};
use rustc_hir::def_id::DefId;
Expand Down Expand Up @@ -656,7 +656,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};

if let Ok(rest_snippet) = rest_snippet {
let sugg = if callee_expr.precedence().order() >= PREC_POSTFIX {
let sugg = if callee_expr.precedence().order() >= PREC_UNAMBIGUOUS {
vec![
(up_to_rcvr_span, "".to_string()),
(rest_span, format!(".{}({rest_snippet}", segment.ident)),
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_hir_typeck/src/cast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -946,7 +946,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {

fn lossy_provenance_ptr2int_lint(&self, fcx: &FnCtxt<'a, 'tcx>, t_c: ty::cast::IntTy) {
let expr_prec = self.expr.precedence().order();
let needs_parens = expr_prec < rustc_ast::util::parser::PREC_POSTFIX;
let needs_parens = expr_prec < rustc_ast::util::parser::PREC_UNAMBIGUOUS;

let needs_cast = !matches!(t_c, ty::cast::IntTy::U(ty::UintTy::Usize));
let cast_span = self.expr_span.shrink_to_hi().to(self.cast_span);
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
use core::cmp::min;
use core::iter;
use hir::def_id::LocalDefId;
use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX};
use rustc_ast::util::parser::{ExprPrecedence, PREC_UNAMBIGUOUS};
use rustc_data_structures::packed::Pu128;
use rustc_errors::{Applicability, Diag, MultiSpan};
use rustc_hir as hir;
Expand Down Expand Up @@ -1287,7 +1287,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
{
let span = expr.span.find_oldest_ancestor_in_same_ctxt();

let mut sugg = if expr.precedence().order() >= PREC_POSTFIX {
let mut sugg = if expr.precedence().order() >= PREC_UNAMBIGUOUS {
vec![(span.shrink_to_hi(), ".into()".to_owned())]
} else {
vec![
Expand Down Expand Up @@ -2826,7 +2826,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
"change the type of the numeric literal from `{checked_ty}` to `{expected_ty}`",
);

let close_paren = if expr.precedence().order() < PREC_POSTFIX {
let close_paren = if expr.precedence().order() < PREC_UNAMBIGUOUS {
sugg.push((expr.span.shrink_to_lo(), "(".to_string()));
")"
} else {
Expand All @@ -2851,7 +2851,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let len = src.trim_end_matches(&checked_ty.to_string()).len();
expr.span.with_lo(expr.span.lo() + BytePos(len as u32))
},
if expr.precedence().order() < PREC_POSTFIX {
if expr.precedence().order() < PREC_UNAMBIGUOUS {
// Readd `)`
format!("{expected_ty})")
} else {
Expand Down
6 changes: 3 additions & 3 deletions src/tools/clippy/clippy_lints/src/dereference.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ use clippy_utils::{
expr_use_ctxt, get_parent_expr, is_block_like, is_lint_allowed, path_to_local, DefinedTy, ExprUseNode,
};
use core::mem;
use rustc_ast::util::parser::{PREC_POSTFIX, PREC_PREFIX};
use rustc_ast::util::parser::{PREC_UNAMBIGUOUS, PREC_PREFIX};
use rustc_data_structures::fx::FxIndexMap;
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_ty, Visitor};
Expand Down Expand Up @@ -1013,7 +1013,7 @@ fn report<'tcx>(
let (precedence, calls_field) = match cx.tcx.parent_hir_node(data.first_expr.hir_id) {
Node::Expr(e) => match e.kind {
ExprKind::Call(callee, _) if callee.hir_id != data.first_expr.hir_id => (0, false),
ExprKind::Call(..) => (PREC_POSTFIX, matches!(expr.kind, ExprKind::Field(..))),
ExprKind::Call(..) => (PREC_UNAMBIGUOUS, matches!(expr.kind, ExprKind::Field(..))),
_ => (e.precedence().order(), false),
},
_ => (0, false),
Expand Down Expand Up @@ -1160,7 +1160,7 @@ impl<'tcx> Dereferencing<'tcx> {
},
Some(parent) if !parent.span.from_expansion() => {
// Double reference might be needed at this point.
if parent.precedence().order() == PREC_POSTFIX {
if parent.precedence().order() == PREC_UNAMBIGUOUS {
// Parentheses would be needed here, don't lint.
*outer_pat = None;
} else {
Expand Down
4 changes: 2 additions & 2 deletions src/tools/clippy/clippy_lints/src/matches/manual_utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ use clippy_utils::{
can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local_id,
peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, CaptureKind,
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_ast::util::parser::PREC_UNAMBIGUOUS;
use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::LangItem::{OptionNone, OptionSome};
Expand Down Expand Up @@ -117,7 +117,7 @@ where
// it's being passed by value.
let scrutinee = peel_hir_expr_refs(scrutinee).0;
let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
let scrutinee_str = if scrutinee.span.eq_ctxt(expr.span) && scrutinee.precedence().order() < PREC_POSTFIX {
let scrutinee_str = if scrutinee.span.eq_ctxt(expr.span) && scrutinee.precedence().order() < PREC_UNAMBIGUOUS {
format!("({scrutinee_str})")
} else {
scrutinee_str.into()
Expand Down

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