diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs index ab1dd46fe33..4b1374ceef3 100644 --- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs +++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs @@ -213,7 +213,9 @@ impl<'a> State<'a> { fn print_expr_call(&mut self, func: &ast::Expr, args: &[P], fixup: FixupContext) { let needs_paren = match func.kind { - ast::ExprKind::Field(..) => true, + // In order to call a named field, needs parens: `(self.fun)()` + // But not for an unnamed field: `self.0()` + ast::ExprKind::Field(_, name) => !name.is_numeric(), _ => func.precedence() < ExprPrecedence::Unambiguous, }; diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs index aab4e1b1afc..7df7e732925 100644 --- a/compiler/rustc_parse/src/parser/diagnostics.rs +++ b/compiler/rustc_parse/src/parser/diagnostics.rs @@ -1336,7 +1336,7 @@ impl<'a> Parser<'a> { ) -> bool { if let ExprKind::Binary(op, l1, r1) = &inner_op.kind { if let ExprKind::Field(_, ident) = l1.kind - && ident.as_str().parse::().is_err() + && !ident.is_numeric() && !matches!(r1.kind, ExprKind::Lit(_)) { // The parser has encountered `foo.bar bool { self.name.can_be_raw() && self.is_reserved() } + + /// Whether this would be the identifier for a tuple field like `self.0`, as + /// opposed to a named field like `self.thing`. + pub fn is_numeric(self) -> bool { + !self.name.is_empty() && self.as_str().bytes().all(|b| b.is_ascii_digit()) + } } /// Collect all the keywords in a given edition into a vector. diff --git a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs index dc45731dce7..2b41020d307 100644 --- a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs +++ b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs @@ -77,6 +77,9 @@ static EXPRS: &[&str] = &[ // These mean different things. "if let _ = true && false {}", "if let _ = (true && false) {}", + // Parentheses to call a named field, but not an unnamed field. + "(self.fun)()", + "self.0()", // Conditions end at the first curly brace, so struct expressions need to be // parenthesized. Except in a match guard, where conditions end at arrow. "if let _ = (Struct {}) {}",