src/doc/rustc-dev-guide/examples/rustc-driver-getting-diagnostics.rs

   1 #![feature(rustc_private)]
   2
   3 extern crate rustc_driver;
   4 extern crate rustc_error_codes;
   5 extern crate rustc_errors;
   6 extern crate rustc_hash;
   7 extern crate rustc_hir;
   8 extern crate rustc_interface;
   9 extern crate rustc_session;
  10 extern crate rustc_span;
  11
  12 use rustc_errors::registry;
  13 use rustc_session::config::{self, CheckCfg};
  14 use rustc_span::source_map;
  15 use std::io;
  16 use std::path;
  17 use std::process;
  18 use std::str;
  19 use std::sync;
  20
  21 // Buffer diagnostics in a Vec<u8>.
  22 #[derive(Clone)]
  23 pub struct DiagnosticSink(sync::Arc<sync::Mutex<Vec<u8>>>);
  24
  25 impl io::Write for DiagnosticSink {
  26     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
  27         self.0.lock().unwrap().write(buf)
  28     }
  29     fn flush(&mut self) -> io::Result<()> {
  30         self.0.lock().unwrap().flush()
  31     }
  32 }
  33
  34 fn main() {
  35     let out = process::Command::new("rustc")
  36         .arg("--print=sysroot")
  37         .current_dir(".")
  38         .output()
  39         .unwrap();
  40     let sysroot = str::from_utf8(&out.stdout).unwrap().trim();
  41     let buffer = sync::Arc::new(sync::Mutex::new(Vec::new()));
  42     let config = rustc_interface::Config {
  43         opts: config::Options {
  44             maybe_sysroot: Some(path::PathBuf::from(sysroot)),
  45             // Configure the compiler to emit diagnostics in compact JSON format.
  46             error_format: config::ErrorOutputType::Json {
  47                 pretty: false,
  48                 json_rendered: rustc_errors::emitter::HumanReadableErrorType::Default(
  49                     rustc_errors::emitter::ColorConfig::Never,
  50                 ),
  51             },
  52             ..config::Options::default()
  53         },
  54         // This program contains a type error.
  55         input: config::Input::Str {
  56             name: source_map::FileName::Custom("main.rs".into()),
  57             input: "
  58 fn main() {
  59     let x: &str = 1;
  60 }
  61 "
  62             .into(),
  63         },
  64         crate_cfg: rustc_hash::FxHashSet::default(),
  65         crate_check_cfg: CheckCfg::default(),
  66         output_dir: None,
  67         output_file: None,
  68         file_loader: None,
  69         locale_resources: rustc_driver::DEFAULT_LOCALE_RESOURCES,
  70         lint_caps: rustc_hash::FxHashMap::default(),
  71         parse_sess_created: None,
  72         register_lints: None,
  73         override_queries: None,
  74         registry: registry::Registry::new(&rustc_error_codes::DIAGNOSTICS),
  75         make_codegen_backend: None,
  76     };
  77     rustc_interface::run_compiler(config, |compiler| {
  78         compiler.enter(|queries| {
  79             queries.global_ctxt().unwrap().enter(|tcx| {
  80                 // Run the analysis phase on the local crate to trigger the type error.
  81                 let _ = tcx.analysis(());
  82             });
  83         });
  84     });
  85     // Read buffered diagnostics.
  86     let diagnostics = String::from_utf8(buffer.lock().unwrap().clone()).unwrap();
  87     println!("{diagnostics}");
  88 }