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use libsyntax2::{
File, TextUnit, AstNode,
ast::self,
algo::{
ancestors,
},
};
use {
AtomEdit, find_node_at_offset,
scope::FnScopes,
};
#[derive(Debug)]
pub struct CompletionItem {
pub name: String,
}
pub fn scope_completion(file: &File, offset: TextUnit) -> Option<Vec<CompletionItem>> {
// Insert a fake ident to get a valid parse tree
let file = {
let edit = AtomEdit::insert(offset, "intellijRulezz".to_string());
// Don't bother with completion if incremental reparse fails
file.incremental_reparse(&edit)?
};
let name_ref = find_node_at_offset::<ast::NameRef>(file.syntax(), offset)?;
let fn_def = ancestors(name_ref.syntax()).filter_map(ast::FnDef::cast).next()?;
let scopes = FnScopes::new(fn_def);
Some(complete(name_ref, &scopes))
}
fn complete(name_ref: ast::NameRef, scopes: &FnScopes) -> Vec<CompletionItem> {
scopes.scope_chain(name_ref.syntax())
.flat_map(|scope| scopes.entries(scope).iter())
.map(|entry| CompletionItem {
name: entry.name().to_string()
})
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
use test_utils::{assert_eq_dbg, extract_offset};
fn do_check(code: &str, expected_completions: &str) {
let (off, code) = extract_offset(&code);
let file = File::parse(&code);
let completions = scope_completion(&file, off).unwrap();
assert_eq_dbg(expected_completions, &completions);
}
#[test]
fn test_completion_let_scope() {
do_check(r"
fn quux(x: i32) {
let y = 92;
1 + <|>;
let z = ();
}
", r#"[CompletionItem { name: "y" },
CompletionItem { name: "x" }]"#);
}
#[test]
fn test_completion_if_let_scope() {
do_check(r"
fn quux() {
if let Some(x) = foo() {
let y = 92;
};
if let Some(a) = bar() {
let b = 62;
1 + <|>
}
}
", r#"[CompletionItem { name: "b" },
CompletionItem { name: "a" }]"#);
}
#[test]
fn test_completion_for_scope() {
do_check(r"
fn quux() {
for x in &[1, 2, 3] {
<|>
}
}
", r#"[CompletionItem { name: "x" }]"#);
}
}
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