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Diffstat (limited to 'third_party/rust/syn/tests/test_precedence.rs')
| -rw-r--r-- | third_party/rust/syn/tests/test_precedence.rs | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/third_party/rust/syn/tests/test_precedence.rs b/third_party/rust/syn/tests/test_precedence.rs new file mode 100644 index 0000000000..dbcd74f163 --- /dev/null +++ b/third_party/rust/syn/tests/test_precedence.rs @@ -0,0 +1,460 @@ +#![cfg(not(syn_disable_nightly_tests))] +#![cfg(not(miri))] +#![recursion_limit = "1024"] +#![feature(rustc_private)] +#![allow( + clippy::explicit_deref_methods, + clippy::manual_assert, + clippy::match_wildcard_for_single_variants, + clippy::too_many_lines +)] + +//! The tests in this module do the following: +//! +//! 1. Parse a given expression in both `syn` and `librustc`. +//! 2. Fold over the expression adding brackets around each subexpression (with +//! some complications - see the `syn_brackets` and `librustc_brackets` +//! methods). +//! 3. Serialize the `syn` expression back into a string, and re-parse it with +//! `librustc`. +//! 4. Respan all of the expressions, replacing the spans with the default +//! spans. +//! 5. Compare the expressions with one another, if they are not equal fail. + +extern crate rustc_ast; +extern crate rustc_data_structures; +extern crate rustc_span; +extern crate thin_vec; + +use crate::common::eq::SpanlessEq; +use crate::common::parse; +use quote::quote; +use rayon::iter::{IntoParallelIterator, ParallelIterator}; +use regex::Regex; +use rustc_ast::ast; +use rustc_ast::ptr::P; +use rustc_span::edition::Edition; +use std::fs; +use std::process; +use std::sync::atomic::{AtomicUsize, Ordering}; +use walkdir::{DirEntry, WalkDir}; + +#[macro_use] +mod macros; + +#[allow(dead_code)] +mod common; + +mod repo; + +/// Test some pre-set expressions chosen by us. +#[test] +fn test_simple_precedence() { + const EXPRS: &[&str] = &[ + "1 + 2 * 3 + 4", + "1 + 2 * ( 3 + 4 )", + "{ for i in r { } *some_ptr += 1; }", + "{ loop { break 5; } }", + "{ if true { () }.mthd() }", + "{ for i in unsafe { 20 } { } }", + ]; + + let mut failed = 0; + + for input in EXPRS { + let expr = if let Some(expr) = parse::syn_expr(input) { + expr + } else { + failed += 1; + continue; + }; + + let pf = match test_expressions(Edition::Edition2018, vec![expr]) { + (1, 0) => "passed", + (0, 1) => { + failed += 1; + "failed" + } + _ => unreachable!(), + }; + errorf!("=== {}: {}\n", input, pf); + } + + if failed > 0 { + panic!("Failed {} tests", failed); + } +} + +/// Test expressions from rustc, like in `test_round_trip`. +#[test] +fn test_rustc_precedence() { + common::rayon_init(); + repo::clone_rust(); + let abort_after = common::abort_after(); + if abort_after == 0 { + panic!("Skipping all precedence tests"); + } + + let passed = AtomicUsize::new(0); + let failed = AtomicUsize::new(0); + + // 2018 edition is hard + let edition_regex = Regex::new(r"\b(async|try)[!(]").unwrap(); + + WalkDir::new("tests/rust") + .sort_by(|a, b| a.file_name().cmp(b.file_name())) + .into_iter() + .filter_entry(repo::base_dir_filter) + .collect::<Result<Vec<DirEntry>, walkdir::Error>>() + .unwrap() + .into_par_iter() + .for_each(|entry| { + let path = entry.path(); + if path.is_dir() { + return; + } + + let content = fs::read_to_string(path).unwrap(); + let content = edition_regex.replace_all(&content, "_$0"); + + let (l_passed, l_failed) = match syn::parse_file(&content) { + Ok(file) => { + let edition = repo::edition(path).parse().unwrap(); + let exprs = collect_exprs(file); + test_expressions(edition, exprs) + } + Err(msg) => { + errorf!("syn failed to parse\n{:?}\n", msg); + (0, 1) + } + }; + + errorf!( + "=== {}: {} passed | {} failed\n", + path.display(), + l_passed, + l_failed + ); + + passed.fetch_add(l_passed, Ordering::Relaxed); + let prev_failed = failed.fetch_add(l_failed, Ordering::Relaxed); + + if prev_failed + l_failed >= abort_after { + process::exit(1); + } + }); + + let passed = passed.load(Ordering::Relaxed); + let failed = failed.load(Ordering::Relaxed); + + errorf!("\n===== Precedence Test Results =====\n"); + errorf!("{} passed | {} failed\n", passed, failed); + + if failed > 0 { + panic!("{} failures", failed); + } +} + +fn test_expressions(edition: Edition, exprs: Vec<syn::Expr>) -> (usize, usize) { + let mut passed = 0; + let mut failed = 0; + + rustc_span::create_session_if_not_set_then(edition, |_| { + for expr in exprs { + let raw = quote!(#expr).to_string(); + + let librustc_ast = if let Some(e) = librustc_parse_and_rewrite(&raw) { + e + } else { + failed += 1; + errorf!("\nFAIL - librustc failed to parse raw\n"); + continue; + }; + + let syn_expr = syn_brackets(expr); + let syn_ast = if let Some(e) = parse::librustc_expr("e!(#syn_expr).to_string()) { + e + } else { + failed += 1; + errorf!("\nFAIL - librustc failed to parse bracketed\n"); + continue; + }; + + if SpanlessEq::eq(&syn_ast, &librustc_ast) { + passed += 1; + } else { + failed += 1; + errorf!("\nFAIL\n{:?}\n!=\n{:?}\n", syn_ast, librustc_ast); + } + } + }); + + (passed, failed) +} + +fn librustc_parse_and_rewrite(input: &str) -> Option<P<ast::Expr>> { + parse::librustc_expr(input).and_then(librustc_brackets) +} + +/// Wrap every expression which is not already wrapped in parens with parens, to +/// reveal the precedence of the parsed expressions, and produce a stringified +/// form of the resulting expression. +/// +/// This method operates on librustc objects. +fn librustc_brackets(mut librustc_expr: P<ast::Expr>) -> Option<P<ast::Expr>> { + use rustc_ast::ast::{ + Attribute, Block, BorrowKind, Expr, ExprField, ExprKind, GenericArg, Local, LocalKind, Pat, + Stmt, StmtKind, StructExpr, StructRest, Ty, + }; + use rustc_ast::mut_visit::{noop_visit_generic_arg, noop_visit_local, MutVisitor}; + use rustc_data_structures::map_in_place::MapInPlace; + use rustc_span::DUMMY_SP; + use std::mem; + use std::ops::DerefMut; + use thin_vec::ThinVec; + + struct BracketsVisitor { + failed: bool, + } + + fn flat_map_field<T: MutVisitor>(mut f: ExprField, vis: &mut T) -> Vec<ExprField> { + if f.is_shorthand { + noop_visit_expr(&mut f.expr, vis); + } else { + vis.visit_expr(&mut f.expr); + } + vec![f] + } + + fn flat_map_stmt<T: MutVisitor>(stmt: Stmt, vis: &mut T) -> Vec<Stmt> { + let kind = match stmt.kind { + // Don't wrap toplevel expressions in statements. + StmtKind::Expr(mut e) => { + noop_visit_expr(&mut e, vis); + StmtKind::Expr(e) + } + StmtKind::Semi(mut e) => { + noop_visit_expr(&mut e, vis); + StmtKind::Semi(e) + } + s => s, + }; + + vec![Stmt { kind, ..stmt }] + } + + fn noop_visit_expr<T: MutVisitor>(e: &mut Expr, vis: &mut T) { + use rustc_ast::mut_visit::{noop_visit_expr, visit_attrs}; + match &mut e.kind { + ExprKind::AddrOf(BorrowKind::Raw, ..) => {} + ExprKind::Struct(expr) => { + let StructExpr { + qself, + path, + fields, + rest, + } = expr.deref_mut(); + vis.visit_qself(qself); + vis.visit_path(path); + fields.flat_map_in_place(|field| flat_map_field(field, vis)); + if let StructRest::Base(rest) = rest { + vis.visit_expr(rest); + } + vis.visit_id(&mut e.id); + vis.visit_span(&mut e.span); + visit_attrs(&mut e.attrs, vis); + } + _ => noop_visit_expr(e, vis), + } + } + + impl MutVisitor for BracketsVisitor { + fn visit_expr(&mut self, e: &mut P<Expr>) { + match e.kind { + ExprKind::ConstBlock(..) => {} + _ => noop_visit_expr(e, self), + } + match e.kind { + ExprKind::If(..) | ExprKind::Block(..) | ExprKind::Let(..) => {} + _ => { + let inner = mem::replace( + e, + P(Expr { + id: ast::DUMMY_NODE_ID, + kind: ExprKind::Err, + span: DUMMY_SP, + attrs: ThinVec::new(), + tokens: None, + }), + ); + e.kind = ExprKind::Paren(inner); + } + } + } + + fn visit_generic_arg(&mut self, arg: &mut GenericArg) { + match arg { + // Don't wrap unbraced const generic arg as that's invalid syntax. + GenericArg::Const(anon_const) => { + if let ExprKind::Block(..) = &mut anon_const.value.kind { + noop_visit_expr(&mut anon_const.value, self); + } + } + _ => noop_visit_generic_arg(arg, self), + } + } + + fn visit_block(&mut self, block: &mut P<Block>) { + self.visit_id(&mut block.id); + block + .stmts + .flat_map_in_place(|stmt| flat_map_stmt(stmt, self)); + self.visit_span(&mut block.span); + } + + fn visit_local(&mut self, local: &mut P<Local>) { + match local.kind { + LocalKind::InitElse(..) => {} + _ => noop_visit_local(local, self), + } + } + + // We don't want to look at expressions that might appear in patterns or + // types yet. We'll look into comparing those in the future. For now + // focus on expressions appearing in other places. + fn visit_pat(&mut self, pat: &mut P<Pat>) { + _ = pat; + } + + fn visit_ty(&mut self, ty: &mut P<Ty>) { + _ = ty; + } + + fn visit_attribute(&mut self, attr: &mut Attribute) { + _ = attr; + } + } + + let mut folder = BracketsVisitor { failed: false }; + folder.visit_expr(&mut librustc_expr); + if folder.failed { + None + } else { + Some(librustc_expr) + } +} + +/// Wrap every expression which is not already wrapped in parens with parens, to +/// reveal the precedence of the parsed expressions, and produce a stringified +/// form of the resulting expression. +fn syn_brackets(syn_expr: syn::Expr) -> syn::Expr { + use syn::fold::{fold_expr, fold_generic_argument, fold_generic_method_argument, Fold}; + use syn::{token, Expr, ExprParen, GenericArgument, GenericMethodArgument, Pat, Stmt, Type}; + + struct ParenthesizeEveryExpr; + impl Fold for ParenthesizeEveryExpr { + fn fold_expr(&mut self, expr: Expr) -> Expr { + match expr { + Expr::Group(_) => unreachable!(), + Expr::If(..) | Expr::Unsafe(..) | Expr::Block(..) | Expr::Let(..) => { + fold_expr(self, expr) + } + _ => Expr::Paren(ExprParen { + attrs: Vec::new(), + expr: Box::new(fold_expr(self, expr)), + paren_token: token::Paren::default(), + }), + } + } + + fn fold_generic_argument(&mut self, arg: GenericArgument) -> GenericArgument { + match arg { + GenericArgument::Const(arg) => GenericArgument::Const(match arg { + Expr::Block(_) => fold_expr(self, arg), + // Don't wrap unbraced const generic arg as that's invalid syntax. + _ => arg, + }), + _ => fold_generic_argument(self, arg), + } + } + + fn fold_generic_method_argument( + &mut self, + arg: GenericMethodArgument, + ) -> GenericMethodArgument { + match arg { + GenericMethodArgument::Const(arg) => GenericMethodArgument::Const(match arg { + Expr::Block(_) => fold_expr(self, arg), + // Don't wrap unbraced const generic arg as that's invalid syntax. + _ => arg, + }), + _ => fold_generic_method_argument(self, arg), + } + } + + fn fold_stmt(&mut self, stmt: Stmt) -> Stmt { + match stmt { + // Don't wrap toplevel expressions in statements. + Stmt::Expr(e) => Stmt::Expr(fold_expr(self, e)), + Stmt::Semi(e, semi) => { + if let Expr::Verbatim(_) = e { + Stmt::Semi(e, semi) + } else { + Stmt::Semi(fold_expr(self, e), semi) + } + } + s => s, + } + } + + // We don't want to look at expressions that might appear in patterns or + // types yet. We'll look into comparing those in the future. For now + // focus on expressions appearing in other places. + fn fold_pat(&mut self, pat: Pat) -> Pat { + pat + } + + fn fold_type(&mut self, ty: Type) -> Type { + ty + } + } + + let mut folder = ParenthesizeEveryExpr; + folder.fold_expr(syn_expr) +} + +/// Walk through a crate collecting all expressions we can find in it. +fn collect_exprs(file: syn::File) -> Vec<syn::Expr> { + use syn::fold::Fold; + use syn::punctuated::Punctuated; + use syn::{token, ConstParam, Expr, ExprTuple, Path}; + + struct CollectExprs(Vec<Expr>); + impl Fold for CollectExprs { + fn fold_expr(&mut self, expr: Expr) -> Expr { + match expr { + Expr::Verbatim(_) => {} + _ => self.0.push(expr), + } + + Expr::Tuple(ExprTuple { + attrs: vec![], + elems: Punctuated::new(), + paren_token: token::Paren::default(), + }) + } + + fn fold_path(&mut self, path: Path) -> Path { + // Skip traversing into const generic path arguments + path + } + + fn fold_const_param(&mut self, const_param: ConstParam) -> ConstParam { + const_param + } + } + + let mut folder = CollectExprs(vec![]); + folder.fold_file(file); + folder.0 +} |