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#![feature(rustc_private)]
// NOTE: For the example to compile, you will need to first run the following:
// rustup component add rustc-dev llvm-tools-preview
// version: rustc 1.68.0-nightly (935dc0721 2022-12-19)
extern crate rustc_ast_pretty;
extern crate rustc_error_codes;
extern crate rustc_errors;
extern crate rustc_hash;
extern crate rustc_hir;
extern crate rustc_interface;
extern crate rustc_session;
extern crate rustc_span;
use std::{path, process, str};
use rustc_ast_pretty::pprust::item_to_string;
use rustc_errors::registry;
use rustc_session::config::{self, CheckCfg};
use rustc_span::source_map;
fn main() {
let out = process::Command::new("rustc")
.arg("--print=sysroot")
.current_dir(".")
.output()
.unwrap();
let sysroot = str::from_utf8(&out.stdout).unwrap().trim();
let config = rustc_interface::Config {
opts: config::Options {
maybe_sysroot: Some(path::PathBuf::from(sysroot)),
..config::Options::default()
},
input: config::Input::Str {
name: source_map::FileName::Custom("main.rs".to_string()),
input: r#"
fn main() {
let message = "Hello, World!";
println!("{message}");
}
"#
.to_string(),
},
crate_cfg: rustc_hash::FxHashSet::default(),
crate_check_cfg: CheckCfg::default(),
input_path: None,
output_dir: None,
output_file: None,
file_loader: None,
lint_caps: rustc_hash::FxHashMap::default(),
parse_sess_created: None,
register_lints: None,
override_queries: None,
make_codegen_backend: None,
registry: registry::Registry::new(&rustc_error_codes::DIAGNOSTICS),
};
rustc_interface::run_compiler(config, |compiler| {
compiler.enter(|queries| {
// TODO: add this to -Z unpretty
let ast_krate = queries.parse().unwrap().take();
for item in ast_krate.items {
println!("{}", item_to_string(&item));
}
// Analyze the crate and inspect the types under the cursor.
queries.global_ctxt().unwrap().take().enter(|tcx| {
// Every compilation contains a single crate.
let hir_krate = tcx.hir();
// Iterate over the top-level items in the crate, looking for the main function.
for id in hir_krate.items() {
let item = hir_krate.item(id);
// Use pattern-matching to find a specific node inside the main function.
if let rustc_hir::ItemKind::Fn(_, _, body_id) = item.kind {
let expr = &tcx.hir().body(body_id).value;
if let rustc_hir::ExprKind::Block(block, _) = expr.kind {
if let rustc_hir::StmtKind::Local(local) = block.stmts[0].kind {
if let Some(expr) = local.init {
let hir_id = expr.hir_id; // hir_id identifies the string "Hello, world!"
let def_id = tcx.hir().local_def_id(item.hir_id()); // def_id identifies the main function
let ty = tcx.typeck(def_id).node_type(hir_id);
println!("{expr:#?}: {ty:?}");
}
}
}
}
}
})
});
});
}
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