rust/crates/ide-assists/src/handlers/remove_unused_param.rs

411 lines
8.9 KiB
Rust

use ide_db::{base_db::FileId, defs::Definition, search::FileReference};
use syntax::{
algo::find_node_at_range,
ast::{self, HasArgList},
AstNode, SourceFile, SyntaxKind, SyntaxNode, TextRange, T,
};
use SyntaxKind::WHITESPACE;
use crate::{
assist_context::SourceChangeBuilder, utils::next_prev, AssistContext, AssistId, AssistKind,
Assists,
};
// Assist: remove_unused_param
//
// Removes unused function parameter.
//
// ```
// fn frobnicate(x: i32$0) {}
//
// 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 is_self_present =
param.syntax().parent()?.children().find_map(ast::SelfParam::cast).is_some();
// check if fn is in impl Trait for ..
if func
.syntax()
.parent() // AssocItemList
.and_then(|x| x.parent())
.and_then(ast::Impl::cast)
.map_or(false, |imp| imp.trait_().is_some())
{
cov_mark::hit!(trait_impl);
return None;
}
let mut param_position = func.param_list()?.params().position(|it| it == param)?;
// param_list() does not take the self param into consideration, hence this additional check
// is required. For associated functions, param_position is incremented here. For inherent
// calls we revet the increment below, in process_usage, as those calls will not have an
// explicit self parameter.
if is_self_present {
param_position += 1;
}
let fn_def = {
let func = ctx.sema.to_def(&func)?;
Definition::Function(func)
};
let param_def = {
let local = ctx.sema.to_def(&ident_pat)?;
Definition::Local(local)
};
if param_def.usages(&ctx.sema).at_least_one() {
cov_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_to_remove(param.syntax()));
for (file_id, references) in fn_def.usages(&ctx.sema).all() {
process_usages(ctx, builder, file_id, references, param_position, is_self_present);
}
},
)
}
fn process_usages(
ctx: &AssistContext<'_>,
builder: &mut SourceChangeBuilder,
file_id: FileId,
references: Vec<FileReference>,
arg_to_remove: usize,
is_self_present: bool,
) {
let source_file = ctx.sema.parse(file_id);
builder.edit_file(file_id);
let possible_ranges = references
.into_iter()
.filter_map(|usage| process_usage(&source_file, usage, arg_to_remove, is_self_present));
let mut ranges_to_delete: Vec<TextRange> = vec![];
for range in possible_ranges {
if !ranges_to_delete.iter().any(|it| it.contains_range(range)) {
ranges_to_delete.push(range)
}
}
for range in ranges_to_delete {
builder.delete(range)
}
}
fn process_usage(
source_file: &SourceFile,
FileReference { range, .. }: FileReference,
mut arg_to_remove: usize,
is_self_present: bool,
) -> Option<TextRange> {
let call_expr_opt: Option<ast::CallExpr> = find_node_at_range(source_file.syntax(), range);
if let Some(call_expr) = call_expr_opt {
let call_expr_range = call_expr.expr()?.syntax().text_range();
if !call_expr_range.contains_range(range) {
return None;
}
let arg = call_expr.arg_list()?.args().nth(arg_to_remove)?;
return Some(range_to_remove(arg.syntax()));
}
let method_call_expr_opt: Option<ast::MethodCallExpr> =
find_node_at_range(source_file.syntax(), range);
if let Some(method_call_expr) = method_call_expr_opt {
let method_call_expr_range = method_call_expr.name_ref()?.syntax().text_range();
if !method_call_expr_range.contains_range(range) {
return None;
}
if is_self_present {
arg_to_remove -= 1;
}
let arg = method_call_expr.arg_list()?.args().nth(arg_to_remove)?;
return Some(range_to_remove(arg.syntax()));
}
None
}
pub(crate) fn range_to_remove(node: &SyntaxNode) -> TextRange {
let up_to_comma = next_prev().find_map(|dir| {
node.siblings_with_tokens(dir)
.filter_map(|it| it.into_token())
.find(|it| it.kind() == T![,])
.map(|it| (dir, it))
});
if let Some((dir, token)) = up_to_comma {
if node.next_sibling().is_some() {
let up_to_space = token
.siblings_with_tokens(dir)
.skip(1)
.take_while(|it| it.kind() == WHITESPACE)
.last()
.and_then(|it| it.into_token());
return node
.text_range()
.cover(up_to_space.map_or(token.text_range(), |it| it.text_range()));
}
node.text_range().cover(token.text_range())
} else {
node.text_range()
}
}
#[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, $0y: i32) { x; }
fn b() { foo(9, 2,) }
"#,
r#"
fn a() { foo(9) }
fn foo(x: i32) { x; }
fn b() { foo(9, ) }
"#,
);
}
#[test]
fn remove_unused_first_param() {
check_assist(
remove_unused_param,
r#"
fn foo($0x: i32, y: i32) { y; }
fn a() { foo(1, 2) }
fn b() { foo(1, 2,) }
"#,
r#"
fn foo(y: i32) { y; }
fn a() { foo(2) }
fn b() { foo(2,) }
"#,
);
}
#[test]
fn remove_unused_single_param() {
check_assist(
remove_unused_param,
r#"
fn foo($0x: i32) { 0; }
fn a() { foo(1) }
fn b() { foo(1, ) }
"#,
r#"
fn foo() { 0; }
fn a() { foo() }
fn b() { foo( ) }
"#,
);
}
#[test]
fn remove_unused_surrounded_by_parms() {
check_assist(
remove_unused_param,
r#"
fn foo(x: i32, $0y: i32, z: i32) { x; }
fn a() { foo(1, 2, 3) }
fn b() { foo(1, 2, 3,) }
"#,
r#"
fn foo(x: i32, z: i32) { x; }
fn a() { foo(1, 3) }
fn b() { foo(1, 3,) }
"#,
);
}
#[test]
fn remove_unused_qualified_call() {
check_assist(
remove_unused_param,
r#"
mod bar { pub fn foo(x: i32, $0y: i32) { x; } }
fn b() { bar::foo(9, 2) }
"#,
r#"
mod bar { pub fn foo(x: i32) { x; } }
fn b() { bar::foo(9) }
"#,
);
}
#[test]
fn remove_unused_turbofished_func() {
check_assist(
remove_unused_param,
r#"
pub fn foo<T>(x: T, $0y: i32) { x; }
fn b() { foo::<i32>(9, 2) }
"#,
r#"
pub fn foo<T>(x: T) { x; }
fn b() { foo::<i32>(9) }
"#,
);
}
#[test]
fn remove_unused_generic_unused_param_func() {
check_assist(
remove_unused_param,
r#"
pub fn foo<T>(x: i32, $0y: T) { x; }
fn b() { foo::<i32>(9, 2) }
fn b2() { foo(9, 2) }
"#,
r#"
pub fn foo<T>(x: i32) { x; }
fn b() { foo::<i32>(9) }
fn b2() { foo(9) }
"#,
);
}
#[test]
fn keep_used() {
cov_mark::check!(keep_used);
check_assist_not_applicable(
remove_unused_param,
r#"
fn foo(x: i32, $0y: i32) { y; }
fn main() { foo(9, 2) }
"#,
);
}
#[test]
fn trait_impl() {
cov_mark::check!(trait_impl);
check_assist_not_applicable(
remove_unused_param,
r#"
trait Trait {
fn foo(x: i32);
}
impl Trait for () {
fn foo($0x: i32) {}
}
"#,
);
}
#[test]
fn remove_across_files() {
check_assist(
remove_unused_param,
r#"
//- /main.rs
fn foo(x: i32, $0y: i32) { x; }
mod foo;
//- /foo.rs
use super::foo;
fn bar() {
let _ = foo(1, 2);
}
"#,
r#"
//- /main.rs
fn foo(x: i32) { x; }
mod foo;
//- /foo.rs
use super::foo;
fn bar() {
let _ = foo(1);
}
"#,
)
}
#[test]
fn test_remove_method_param() {
check_assist(
remove_unused_param,
r#"
struct S;
impl S { fn f(&self, $0_unused: i32) {} }
fn main() {
S.f(92);
S.f();
S.f(93, 92);
S::f(&S, 92);
}
"#,
r#"
struct S;
impl S { fn f(&self) {} }
fn main() {
S.f();
S.f();
S.f(92);
S::f(&S);
}
"#,
)
}
#[test]
fn nested_call() {
check_assist(
remove_unused_param,
r#"
fn foo(x: i32, $0y: i32) -> i32 {
x
}
fn bar() {
foo(1, foo(2, 3));
}
"#,
r#"
fn foo(x: i32) -> i32 {
x
}
fn bar() {
foo(1);
}
"#,
)
}
}