rust/crates/ide/src/expand_macro.rs
2022-08-01 13:47:09 +02:00

522 lines
13 KiB
Rust

use hir::Semantics;
use ide_db::{
base_db::FileId, helpers::pick_best_token,
syntax_helpers::insert_whitespace_into_node::insert_ws_into, RootDatabase,
};
use syntax::{ast, ted, AstNode, NodeOrToken, SyntaxKind, SyntaxNode, T};
use crate::FilePosition;
pub struct ExpandedMacro {
pub name: String,
pub expansion: String,
}
// Feature: Expand Macro Recursively
//
// Shows the full macro expansion of the macro at current cursor.
//
// |===
// | Editor | Action Name
//
// | VS Code | **rust-analyzer: Expand macro recursively**
// |===
//
// image::https://user-images.githubusercontent.com/48062697/113020648-b3973180-917a-11eb-84a9-ecb921293dc5.gif[]
pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<ExpandedMacro> {
let sema = Semantics::new(db);
let file = sema.parse(position.file_id);
let tok = pick_best_token(file.syntax().token_at_offset(position.offset), |kind| match kind {
SyntaxKind::IDENT => 1,
_ => 0,
})?;
// due to how rust-analyzer works internally, we need to special case derive attributes,
// otherwise they might not get found, e.g. here with the cursor at $0 `#[attr]` would expand:
// ```
// #[attr]
// #[derive($0Foo)]
// struct Bar;
// ```
let derive = sema.descend_into_macros(tok.clone()).into_iter().find_map(|descended| {
let hir_file = sema.hir_file_for(&descended.parent()?);
if !hir_file.is_derive_attr_pseudo_expansion(db) {
return None;
}
let name = descended.parent_ancestors().filter_map(ast::Path::cast).last()?.to_string();
// up map out of the #[derive] expansion
let token = hir::InFile::new(hir_file, descended).upmap(db)?.value;
let attr = token.parent_ancestors().find_map(ast::Attr::cast)?;
let expansions = sema.expand_derive_macro(&attr)?;
let idx = attr
.token_tree()?
.token_trees_and_tokens()
.filter_map(NodeOrToken::into_token)
.take_while(|it| it != &token)
.filter(|it| it.kind() == T![,])
.count();
let expansion =
format(db, SyntaxKind::MACRO_ITEMS, position.file_id, expansions.get(idx).cloned()?);
Some(ExpandedMacro { name, expansion })
});
if derive.is_some() {
return derive;
}
// FIXME: Intermix attribute and bang! expansions
// currently we only recursively expand one of the two types
let mut anc = tok.parent_ancestors();
let (name, expanded, kind) = loop {
let node = anc.next()?;
if let Some(item) = ast::Item::cast(node.clone()) {
if let Some(def) = sema.resolve_attr_macro_call(&item) {
break (
def.name(db).to_string(),
expand_attr_macro_recur(&sema, &item)?,
SyntaxKind::MACRO_ITEMS,
);
}
}
if let Some(mac) = ast::MacroCall::cast(node) {
break (
mac.path()?.segment()?.name_ref()?.to_string(),
expand_macro_recur(&sema, &mac)?,
mac.syntax().parent().map(|it| it.kind()).unwrap_or(SyntaxKind::MACRO_ITEMS),
);
}
};
// FIXME:
// macro expansion may lose all white space information
// But we hope someday we can use ra_fmt for that
let expansion = format(db, kind, position.file_id, expanded);
Some(ExpandedMacro { name, expansion })
}
fn expand_macro_recur(
sema: &Semantics<'_, RootDatabase>,
macro_call: &ast::MacroCall,
) -> Option<SyntaxNode> {
let expanded = sema.expand(macro_call)?.clone_for_update();
expand(sema, expanded, ast::MacroCall::cast, expand_macro_recur)
}
fn expand_attr_macro_recur(
sema: &Semantics<'_, RootDatabase>,
item: &ast::Item,
) -> Option<SyntaxNode> {
let expanded = sema.expand_attr_macro(item)?.clone_for_update();
expand(sema, expanded, ast::Item::cast, expand_attr_macro_recur)
}
fn expand<T: AstNode>(
sema: &Semantics<'_, RootDatabase>,
expanded: SyntaxNode,
f: impl FnMut(SyntaxNode) -> Option<T>,
exp: impl Fn(&Semantics<'_, RootDatabase>, &T) -> Option<SyntaxNode>,
) -> Option<SyntaxNode> {
let children = expanded.descendants().filter_map(f);
let mut replacements = Vec::new();
for child in children {
if let Some(new_node) = exp(sema, &child) {
// check if the whole original syntax is replaced
if expanded == *child.syntax() {
return Some(new_node);
}
replacements.push((child, new_node));
}
}
replacements.into_iter().rev().for_each(|(old, new)| ted::replace(old.syntax(), new));
Some(expanded)
}
fn format(db: &RootDatabase, kind: SyntaxKind, file_id: FileId, expanded: SyntaxNode) -> String {
let expansion = insert_ws_into(expanded).to_string();
_format(db, kind, file_id, &expansion).unwrap_or(expansion)
}
#[cfg(any(test, target_arch = "wasm32", target_os = "emscripten"))]
fn _format(
_db: &RootDatabase,
_kind: SyntaxKind,
_file_id: FileId,
_expansion: &str,
) -> Option<String> {
None
}
#[cfg(not(any(test, target_arch = "wasm32", target_os = "emscripten")))]
fn _format(
db: &RootDatabase,
kind: SyntaxKind,
file_id: FileId,
expansion: &str,
) -> Option<String> {
use ide_db::base_db::{FileLoader, SourceDatabase};
// hack until we get hygiene working (same character amount to preserve formatting as much as possible)
const DOLLAR_CRATE_REPLACE: &str = &"__r_a_";
let expansion = expansion.replace("$crate", DOLLAR_CRATE_REPLACE);
let (prefix, suffix) = match kind {
SyntaxKind::MACRO_PAT => ("fn __(", ": u32);"),
SyntaxKind::MACRO_EXPR | SyntaxKind::MACRO_STMTS => ("fn __() {", "}"),
SyntaxKind::MACRO_TYPE => ("type __ =", ";"),
_ => ("", ""),
};
let expansion = format!("{prefix}{expansion}{suffix}");
let &crate_id = db.relevant_crates(file_id).iter().next()?;
let edition = db.crate_graph()[crate_id].edition;
let mut cmd = std::process::Command::new(toolchain::rustfmt());
cmd.arg("--edition");
cmd.arg(edition.to_string());
let mut rustfmt = cmd
.stdin(std::process::Stdio::piped())
.stdout(std::process::Stdio::piped())
.stderr(std::process::Stdio::piped())
.spawn()
.ok()?;
std::io::Write::write_all(&mut rustfmt.stdin.as_mut()?, expansion.as_bytes()).ok()?;
let output = rustfmt.wait_with_output().ok()?;
let captured_stdout = String::from_utf8(output.stdout).ok()?;
if output.status.success() && !captured_stdout.trim().is_empty() {
let output = captured_stdout.replace(DOLLAR_CRATE_REPLACE, "$crate");
let output = output.trim().strip_prefix(prefix)?;
let output = match kind {
SyntaxKind::MACRO_PAT => {
output.strip_suffix(suffix).or_else(|| output.strip_suffix(": u32,\n);"))?
}
_ => output.strip_suffix(suffix)?,
};
let trim_indent = stdx::trim_indent(output);
tracing::debug!("expand_macro: formatting succeeded");
Some(trim_indent)
} else {
None
}
}
#[cfg(test)]
mod tests {
use expect_test::{expect, Expect};
use crate::fixture;
#[track_caller]
fn check(ra_fixture: &str, expect: Expect) {
let (analysis, pos) = fixture::position(ra_fixture);
let expansion = analysis.expand_macro(pos).unwrap().unwrap();
let actual = format!("{}\n{}", expansion.name, expansion.expansion);
expect.assert_eq(&actual);
}
#[test]
fn macro_expand_as_keyword() {
check(
r#"
macro_rules! bar {
($i:tt) => { $i as _ }
}
fn main() {
let x: u64 = ba$0r!(5i64);
}
"#,
expect![[r#"
bar
5i64 as _"#]],
);
}
#[test]
fn macro_expand_underscore() {
check(
r#"
macro_rules! bar {
($i:tt) => { for _ in 0..$i {} }
}
fn main() {
ba$0r!(42);
}
"#,
expect![[r#"
bar
for _ in 0..42{}"#]],
);
}
#[test]
fn macro_expand_recursive_expansion() {
check(
r#"
macro_rules! bar {
() => { fn b() {} }
}
macro_rules! foo {
() => { bar!(); }
}
macro_rules! baz {
() => { foo!(); }
}
f$0oo!();
"#,
expect![[r#"
foo
fn b(){}
"#]],
);
}
#[test]
fn macro_expand_multiple_lines() {
check(
r#"
macro_rules! foo {
() => {
fn some_thing() -> u32 {
let a = 0;
a + 10
}
}
}
f$0oo!();
"#,
expect![[r#"
foo
fn some_thing() -> u32 {
let a = 0;
a+10
}"#]],
);
}
#[test]
fn macro_expand_match_ast() {
check(
r#"
macro_rules! match_ast {
(match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };
(match ($node:expr) {
$( ast::$ast:ident($it:ident) => $res:block, )*
_ => $catch_all:expr $(,)?
}) => {{
$( if let Some($it) = ast::$ast::cast($node.clone()) $res else )*
{ $catch_all }
}};
}
fn main() {
mat$0ch_ast! {
match container {
ast::TraitDef(it) => {},
ast::ImplDef(it) => {},
_ => { continue },
}
}
}
"#,
expect![[r#"
match_ast
{
if let Some(it) = ast::TraitDef::cast(container.clone()){}
else if let Some(it) = ast::ImplDef::cast(container.clone()){}
else {
{
continue
}
}
}"#]],
);
}
#[test]
fn macro_expand_match_ast_inside_let_statement() {
check(
r#"
macro_rules! match_ast {
(match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };
(match ($node:expr) {}) => {{}};
}
fn main() {
let p = f(|it| {
let res = mat$0ch_ast! { match c {}};
Some(res)
})?;
}
"#,
expect![[r#"
match_ast
{}"#]],
);
}
#[test]
fn macro_expand_inner_macro_rules() {
check(
r#"
macro_rules! foo {
($t:tt) => {{
macro_rules! bar {
() => {
$t
}
}
bar!()
}};
}
fn main() {
foo$0!(42);
}
"#,
expect![[r#"
foo
{
macro_rules! bar {
() => {
42
}
}
42
}"#]],
);
}
#[test]
fn macro_expand_inner_macro_fail_to_expand() {
check(
r#"
macro_rules! bar {
(BAD) => {};
}
macro_rules! foo {
() => {bar!()};
}
fn main() {
let res = fo$0o!();
}
"#,
expect![[r#"
foo
"#]],
);
}
#[test]
fn macro_expand_with_dollar_crate() {
check(
r#"
#[macro_export]
macro_rules! bar {
() => {0};
}
macro_rules! foo {
() => {$crate::bar!()};
}
fn main() {
let res = fo$0o!();
}
"#,
expect![[r#"
foo
0"#]],
);
}
#[test]
fn macro_expand_with_dyn_absolute_path() {
check(
r#"
macro_rules! foo {
() => {fn f<T>(_: &dyn ::std::marker::Copy) {}};
}
fn main() {
let res = fo$0o!();
}
"#,
expect![[r#"
foo
fn f<T>(_: &dyn ::std::marker::Copy){}"#]],
);
}
#[test]
fn macro_expand_derive() {
check(
r#"
//- proc_macros: identity
//- minicore: clone, derive
#[proc_macros::identity]
#[derive(C$0lone)]
struct Foo {}
"#,
expect![[r#"
Clone
impl < >core::clone::Clone for Foo< >{}
"#]],
);
}
#[test]
fn macro_expand_derive2() {
check(
r#"
//- minicore: copy, clone, derive
#[derive(Cop$0y)]
#[derive(Clone)]
struct Foo {}
"#,
expect![[r#"
Copy
impl < >core::marker::Copy for Foo< >{}
"#]],
);
}
#[test]
fn macro_expand_derive_multi() {
check(
r#"
//- minicore: copy, clone, derive
#[derive(Cop$0y, Clone)]
struct Foo {}
"#,
expect![[r#"
Copy
impl < >core::marker::Copy for Foo< >{}
"#]],
);
check(
r#"
//- minicore: copy, clone, derive
#[derive(Copy, Cl$0one)]
struct Foo {}
"#,
expect![[r#"
Clone
impl < >core::clone::Clone for Foo< >{}
"#]],
);
}
}