diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs index ee49246a4bbf3..1dbe44bbe19ba 100644 --- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs +++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs @@ -386,18 +386,43 @@ impl<'a> State<'a> { let ib = self.ibox(INDENT_UNIT); - // The Match subexpression in `match x {} - 1` must be parenthesized if - // it is the leftmost subexpression in a statement: - // - // (match x {}) - 1; - // - // But not otherwise: - // - // let _ = match x {} - 1; - // - // Same applies to a small set of other expression kinds which eagerly - // terminate a statement which opens with them. - let needs_par = fixup.would_cause_statement_boundary(expr); + let needs_par = { + // The Match subexpression in `match x {} - 1` must be parenthesized + // if it is the leftmost subexpression in a statement: + // + // (match x {}) - 1; + // + // But not otherwise: + // + // let _ = match x {} - 1; + // + // Same applies to a small set of other expression kinds which + // eagerly terminate a statement which opens with them. + fixup.would_cause_statement_boundary(expr) + } || { + // If a binary operation ends up with an attribute, such as + // resulting from the following macro expansion, then parentheses + // are required so that the attribute encompasses the right + // subexpression and not just the left one. + // + // #![feature(stmt_expr_attributes)] + // + // macro_rules! add_attr { + // ($e:expr) => { #[attr] $e }; + // } + // + // let _ = add_attr!(1 + 1); + // + // We must pretty-print `#[attr] (1 + 1)` not `#[attr] 1 + 1`. + !attrs.is_empty() + && matches!( + expr.kind, + ast::ExprKind::Binary(..) + | ast::ExprKind::Cast(..) + | ast::ExprKind::Assign(..) + | ast::ExprKind::AssignOp(..) + ) + }; if needs_par { self.popen(); fixup = FixupContext::default(); diff --git a/tests/ui-fulldeps/auxiliary/parser.rs b/tests/ui-fulldeps/auxiliary/parser.rs index be51bd29008aa..8a3705124601e 100644 --- a/tests/ui-fulldeps/auxiliary/parser.rs +++ b/tests/ui-fulldeps/auxiliary/parser.rs @@ -7,15 +7,17 @@ extern crate rustc_parse; extern crate rustc_session; extern crate rustc_span; -use rustc_ast::ast::{DUMMY_NODE_ID, Expr}; -use rustc_ast::mut_visit::MutVisitor; +use rustc_ast::ast::{AttrKind, Attribute, DUMMY_NODE_ID, Expr}; +use rustc_ast::mut_visit::{self, MutVisitor}; use rustc_ast::node_id::NodeId; use rustc_ast::ptr::P; -use rustc_ast::token; +use rustc_ast::token::{self, Token}; +use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree, LazyAttrTokenStream}; use rustc_errors::Diag; use rustc_parse::parser::Recovery; use rustc_session::parse::ParseSess; -use rustc_span::{DUMMY_SP, FileName, Span}; +use rustc_span::{AttrId, DUMMY_SP, FileName, Span}; +use std::sync::Arc; pub fn parse_expr(psess: &ParseSess, source_code: &str) -> Option> { let parser = rustc_parse::unwrap_or_emit_fatal(rustc_parse::new_parser_from_source_str( @@ -46,4 +48,36 @@ impl MutVisitor for Normalize { fn visit_span(&mut self, span: &mut Span) { *span = DUMMY_SP; } + + fn visit_attribute(&mut self, attr: &mut Attribute) { + attr.id = AttrId::from_u32(0); + if let AttrKind::Normal(normal_attr) = &mut attr.kind { + if let Some(tokens) = &mut normal_attr.tokens { + let mut stream = tokens.to_attr_token_stream(); + normalize_attr_token_stream(&mut stream); + *tokens = LazyAttrTokenStream::new_direct(stream); + } + } + mut_visit::walk_attribute(self, attr); + } +} + +fn normalize_attr_token_stream(stream: &mut AttrTokenStream) { + Arc::make_mut(&mut stream.0) + .iter_mut() + .for_each(normalize_attr_token_tree); +} + +fn normalize_attr_token_tree(token: &mut AttrTokenTree) { + match token { + AttrTokenTree::Token(token, _spacing) => { + Normalize.visit_span(&mut token.span); + } + AttrTokenTree::Delimited(dspan, _spacing, _delim, stream) => { + normalize_attr_token_stream(stream); + Normalize.visit_span(&mut dspan.open); + Normalize.visit_span(&mut dspan.close); + } + AttrTokenTree::AttrsTarget(_) => unimplemented!("AttrTokenTree::AttrsTarget"), + } } diff --git a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs index 36916e9785629..3b6cca1f6fd92 100644 --- a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs +++ b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs @@ -88,6 +88,18 @@ static EXPRS: &[&str] = &[ // expressions. "match 2 { _ => 1 - 1 }", "match 2 { _ => ({ 1 }) - 1 }", + // Attributes on a Binary, Cast, Assign, and AssignOp expression require + // parentheses. + "#[attr] (1 + 1)", + "#[attr] (1 as T)", + "#[attr] (x = 1)", + "#[attr] (x += 1)", + // If the attribute were not present on the binary operation, it would be + // legal to render this without not just the inner parentheses, but also the + // outer ones. `return x + .. .field` (Yes, really.) Currently the + // pretty-printer does not take advantage of this edge case. + "(return #[attr] (x + ..)).field", + "(return x + ..).field", // Grammar restriction: break value starting with a labeled loop is not // allowed, except if the break is also labeled. "break 'outer 'inner: loop {} + 2", @@ -154,7 +166,12 @@ struct Unparenthesize; impl MutVisitor for Unparenthesize { fn visit_expr(&mut self, e: &mut P) { while let ExprKind::Paren(paren) = &mut e.kind { + let paren_attrs = mem::take(&mut e.attrs); *e = mem::replace(paren, Expr::dummy()); + if !paren_attrs.is_empty() { + assert!(e.attrs.is_empty()); + e.attrs = paren_attrs; + } } mut_visit::walk_expr(self, e); }