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|
use ide_db::{defs::Definition, search::Reference};
use syntax::{
algo::find_node_at_range,
ast::{self, ArgListOwner},
AstNode, SyntaxNode, TextRange, T,
};
use test_utils::mark;
use crate::{
assist_context::AssistBuilder, utils::next_prev, AssistContext, AssistId, AssistKind, Assists,
};
// Assist: remove_unused_param
//
// Removes unused function parameter.
//
// ```
// fn frobnicate(x: i32<|>) {}
//
// fn main() {
// frobnicate(92);
// }
// ```
// ->
// ```
// fn frobnicate() {}
//
// fn main() {
// frobnicate();
// }
// ```
pub(crate) fn remove_unused_param(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let param: ast::Param = ctx.find_node_at_offset()?;
let ident_pat = match param.pat()? {
ast::Pat::IdentPat(it) => it,
_ => return None,
};
let func = param.syntax().ancestors().find_map(ast::Fn::cast)?;
let param_position = func.param_list()?.params().position(|it| it == param)?;
let fn_def = {
let func = ctx.sema.to_def(&func)?;
Definition::ModuleDef(func.into())
};
let param_def = {
let local = ctx.sema.to_def(&ident_pat)?;
Definition::Local(local)
};
if param_def.usages(&ctx.sema).at_least_one() {
mark::hit!(keep_used);
return None;
}
acc.add(
AssistId("remove_unused_param", AssistKind::Refactor),
"Remove unused parameter",
param.syntax().text_range(),
|builder| {
builder.delete(range_with_coma(param.syntax()));
for usage in fn_def.usages(&ctx.sema).all() {
process_usage(ctx, builder, usage, param_position);
}
},
)
}
fn process_usage(
ctx: &AssistContext,
builder: &mut AssistBuilder,
usage: Reference,
arg_to_remove: usize,
) -> Option<()> {
let source_file = ctx.sema.parse(usage.file_range.file_id);
let call_expr: ast::CallExpr =
find_node_at_range(source_file.syntax(), usage.file_range.range)?;
if call_expr.expr()?.syntax().text_range() != usage.file_range.range {
return None;
}
let arg = call_expr.arg_list()?.args().nth(arg_to_remove)?;
builder.edit_file(usage.file_range.file_id);
builder.delete(range_with_coma(arg.syntax()));
Some(())
}
fn range_with_coma(node: &SyntaxNode) -> TextRange {
let up_to = next_prev().find_map(|dir| {
node.siblings_with_tokens(dir)
.filter_map(|it| it.into_token())
.find(|it| it.kind() == T![,])
});
let up_to = up_to.map_or(node.text_range(), |it| it.text_range());
node.text_range().cover(up_to)
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
#[test]
fn remove_unused() {
check_assist(
remove_unused_param,
r#"
fn a() { foo(9, 2) }
fn foo(x: i32, <|>y: i32) { x; }
fn b() { foo(9, 2,) }
"#,
r#"
fn a() { foo(9) }
fn foo(x: i32) { x; }
fn b() { foo(9, ) }
"#,
);
}
#[test]
fn keep_used() {
mark::check!(keep_used);
check_assist_not_applicable(
remove_unused_param,
r#"
fn foo(x: i32, <|>y: i32) { y; }
fn main() { foo(9, 2) }
"#,
);
}
}
|
