use hir::db::ExpandDatabase;
use hir::{ExpandResult, InFile, MacroFileIdExt, Semantics};
use ide_db::base_db::CrateId;
use ide_db::{
helpers::pick_best_token, syntax_helpers::prettify_macro_expansion, FileId, RootDatabase,
};
use span::{Edition, SpanMap, SyntaxContextId, TextRange, TextSize};
use stdx::format_to;
use syntax::{ast, ted, AstNode, NodeOrToken, SyntaxKind, SyntaxNode, T};
use crate::FilePosition;
pub struct ExpandedMacro {
pub name: String,
pub expansion: String,
}
pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<ExpandedMacro> {
let sema = Semantics::new(db);
let file = sema.parse_guess_edition(position.file_id);
let krate = sema.file_to_module_def(position.file_id)?.krate().into();
let tok = pick_best_token(file.syntax().token_at_offset(position.offset), |kind| match kind {
SyntaxKind::IDENT => 1,
_ => 0,
})?;
let derive = sema.descend_into_macros_exact(tok.clone()).into_iter().find_map(|descended| {
let macro_file = sema.hir_file_for(&descended.parent()?).macro_file()?;
if !macro_file.is_derive_attr_pseudo_expansion(db) {
return None;
}
let name = descended.parent_ancestors().filter_map(ast::Path::cast).last()?.to_string();
let InFile { file_id, value: tokens } =
hir::InMacroFile::new(macro_file, descended).upmap_once(db);
let token = sema.parse_or_expand(file_id).covering_element(tokens[0]).into_token()?;
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 ExpandResult { err, value: expansion } = expansions.get(idx)?.clone();
let expansion_file_id = sema.hir_file_for(&expansion).macro_file()?;
let expansion_span_map = db.expansion_span_map(expansion_file_id);
let mut expansion = format(
db,
SyntaxKind::MACRO_ITEMS,
position.file_id,
expansion,
&expansion_span_map,
krate,
);
if let Some(err) = err {
expansion.insert_str(
0,
&format!("Expansion had errors: {}\n\n", err.render_to_string(sema.db)),
);
}
Some(ExpandedMacro { name, expansion })
});
if derive.is_some() {
return derive;
}
let mut anc = tok.parent_ancestors();
let mut span_map = SpanMap::empty();
let mut error = String::new();
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)
.display(
db,
sema.attach_first_edition(position.file_id)
.map(|it| it.edition())
.unwrap_or(Edition::CURRENT),
)
.to_string(),
expand_macro_recur(&sema, &item, &mut error, &mut span_map, TextSize::new(0))?,
SyntaxKind::MACRO_ITEMS,
);
}
}
if let Some(mac) = ast::MacroCall::cast(node) {
let mut name = mac.path()?.segment()?.name_ref()?.to_string();
name.push('!');
let syntax_kind =
mac.syntax().parent().map(|it| it.kind()).unwrap_or(SyntaxKind::MACRO_ITEMS);
break (
name,
expand_macro_recur(
&sema,
&ast::Item::MacroCall(mac),
&mut error,
&mut span_map,
TextSize::new(0),
)?,
syntax_kind,
);
}
};
let mut expansion = format(db, kind, position.file_id, expanded, &span_map, krate);
if !error.is_empty() {
expansion.insert_str(0, &format!("Expansion had errors:{error}\n\n"));
}
Some(ExpandedMacro { name, expansion })
}
fn expand_macro_recur(
sema: &Semantics<'_, RootDatabase>,
macro_call: &ast::Item,
error: &mut String,
result_span_map: &mut SpanMap<SyntaxContextId>,
offset_in_original_node: TextSize,
) -> Option<SyntaxNode> {
let ExpandResult { value: expanded, err } = match macro_call {
item @ ast::Item::MacroCall(macro_call) => {
sema.expand_attr_macro(item).or_else(|| sema.expand_allowed_builtins(macro_call))?
}
item => sema.expand_attr_macro(item)?,
};
let expanded = expanded.clone_for_update();
if let Some(err) = err {
format_to!(error, "\n{}", err.render_to_string(sema.db));
}
let file_id =
sema.hir_file_for(&expanded).macro_file().expect("expansion must produce a macro file");
let expansion_span_map = sema.db.expansion_span_map(file_id);
result_span_map.merge(
TextRange::at(offset_in_original_node, macro_call.syntax().text_range().len()),
expanded.text_range().len(),
&expansion_span_map,
);
Some(expand(sema, expanded, error, result_span_map, u32::from(offset_in_original_node) as i32))
}
fn expand(
sema: &Semantics<'_, RootDatabase>,
expanded: SyntaxNode,
error: &mut String,
result_span_map: &mut SpanMap<SyntaxContextId>,
mut offset_in_original_node: i32,
) -> SyntaxNode {
let children = expanded.descendants().filter_map(ast::Item::cast);
let mut replacements = Vec::new();
for child in children {
if let Some(new_node) = expand_macro_recur(
sema,
&child,
error,
result_span_map,
TextSize::new(
(offset_in_original_node + (u32::from(child.syntax().text_range().start()) as i32))
as u32,
),
) {
offset_in_original_node = offset_in_original_node
+ (u32::from(new_node.text_range().len()) as i32)
- (u32::from(child.syntax().text_range().len()) as i32);
if expanded == *child.syntax() {
return new_node;
}
replacements.push((child, new_node));
}
}
replacements.into_iter().rev().for_each(|(old, new)| ted::replace(old.syntax(), new));
expanded
}
fn format(
db: &RootDatabase,
kind: SyntaxKind,
file_id: FileId,
expanded: SyntaxNode,
span_map: &SpanMap<SyntaxContextId>,
krate: CrateId,
) -> String {
let expansion = prettify_macro_expansion(db, expanded, span_map, krate).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> {
use itertools::Itertools;
Some(expansion.lines().map(|x| x.trim_end()).join("\n"))
}
#[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};
const DOLLAR_CRATE_REPLACE: &str = "__r_a_";
const BUILTIN_REPLACE: &str = "builtin__POUND";
let expansion =
expansion.replace("$crate", DOLLAR_CRATE_REPLACE).replace("builtin #", BUILTIN_REPLACE);
let (prefix, suffix) = match kind {
SyntaxKind::MACRO_PAT => ("fn __(", ": u32);"),
SyntaxKind::MACRO_EXPR | SyntaxKind::MACRO_STMTS => ("fn __() {", "}"),
SyntaxKind::MACRO_TYPE => ("type __ =", ";"),
_ => ("", ""),
};
let expansion = format!("{prefix}{expansion}{suffix}");
let &crate_id = db.relevant_crates(file_id).iter().next()?;
let edition = db.crate_graph()[crate_id].edition;
let mut cmd = std::process::Command::new(toolchain::Tool::Rustfmt.path());
cmd.arg("--edition");
cmd.arg(edition.to_string());
let mut rustfmt = cmd
.stdin(std::process::Stdio::piped())
.stdout(std::process::Stdio::piped())
.stderr(std::process::Stdio::piped())
.spawn()
.ok()?;
std::io::Write::write_all(&mut rustfmt.stdin.as_mut()?, expansion.as_bytes()).ok()?;
let output = rustfmt.wait_with_output().ok()?;
let captured_stdout = String::from_utf8(output.stdout).ok()?;
if output.status.success() && !captured_stdout.trim().is_empty() {
let output = captured_stdout
.replace(DOLLAR_CRATE_REPLACE, "$crate")
.replace(BUILTIN_REPLACE, "builtin #");
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 expand_allowed_builtin_macro() {
check(
r#"
//- minicore: concat
$0concat!("test", 10, 'b', true);"#,
expect![[r#"
concat!
"test10btrue""#]],
);
}
#[test]
fn do_not_expand_disallowed_macro() {
let (analysis, pos) = fixture::position(
r#"
//- minicore: asm
$0asm!("0x300, x0");"#,
);
let expansion = analysis.expand_macro(pos).unwrap();
assert!(expansion.is_none());
}
#[test]
fn macro_expand_as_keyword() {
check(
r#"
macro_rules! bar {
($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$0o!();
}
"#,
expect![[r#"
foo!
Expansion had errors:
expected ident: `BAD`
"#]],
);
}
#[test]
fn macro_expand_with_dollar_crate() {
check(
r#"
#[macro_export]
macro_rules! bar {
() => {0};
}
macro_rules! foo {
() => {$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< >where {
fn clone(&self) -> Self {
match self {
Foo{}
=> 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< >where{}"#]],
);
}
#[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< >where{}"#]],
);
check(
r#"
//- minicore: copy, clone, derive
#[derive(Copy, Cl$0one)]
struct Foo {}
"#,
expect![[r#"
Clone
impl < >core::clone::Clone for Foo< >where {
fn clone(&self) -> Self {
match self {
Foo{}
=> Foo{}
,
}
}
}"#]],
);
}
#[test]
fn dollar_crate() {
check(
r#"
//- /a.rs crate:a
pub struct Foo;
#[macro_export]
macro_rules! m {
( $i:ident ) => { $crate::Foo; $crate::Foo; $i::Foo; };
}
//- /b.rs crate:b deps:a
pub struct Foo;
#[macro_export]
macro_rules! m {
() => { a::m!($crate); $crate::Foo; $crate::Foo; };
}
//- /c.rs crate:c deps:b,a
pub struct Foo;
#[macro_export]
macro_rules! m {
() => { b::m!(); $crate::Foo; $crate::Foo; };
}
fn bar() {
m$0!();
}
"#,
expect![[r#"
m!
a::Foo;
a::Foo;
b::Foo;
;
b::Foo;
b::Foo;
;
crate::Foo;
crate::Foo;"#]],
);
}
}