rust/crates/assists/src/handlers/extract_function.rs
2021-02-13 22:04:52 +03:00

3043 lines
70 KiB
Rust

use std::iter;
use ast::make;
use either::Either;
use hir::{HirDisplay, Local};
use ide_db::{
defs::{Definition, NameRefClass},
search::{FileReference, ReferenceAccess, SearchScope},
};
use itertools::Itertools;
use stdx::format_to;
use syntax::{
algo::SyntaxRewriter,
ast::{
self,
edit::{AstNodeEdit, IndentLevel},
AstNode,
},
SyntaxElement,
SyntaxKind::{self, BLOCK_EXPR, BREAK_EXPR, COMMENT, PATH_EXPR, RETURN_EXPR},
SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset, WalkEvent, T,
};
use test_utils::mark;
use crate::{
assist_context::{AssistContext, Assists},
AssistId,
};
// Assist: extract_function
//
// Extracts selected statements into new function.
//
// ```
// fn main() {
// let n = 1;
// $0let m = n + 2;
// let k = m + n;$0
// let g = 3;
// }
// ```
// ->
// ```
// fn main() {
// let n = 1;
// fun_name(n);
// let g = 3;
// }
//
// fn $0fun_name(n: i32) {
// let m = n + 2;
// let k = m + n;
// }
// ```
pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
if ctx.frange.range.is_empty() {
return None;
}
let node = ctx.covering_element();
if node.kind() == COMMENT {
mark::hit!(extract_function_in_comment_is_not_applicable);
return None;
}
let node = element_to_node(node);
let body = extraction_target(&node, ctx.frange.range)?;
let vars_used_in_body = vars_used_in_body(ctx, &body);
let self_param = self_param_from_usages(ctx, &body, &vars_used_in_body);
let anchor = if self_param.is_some() { Anchor::Method } else { Anchor::Freestanding };
let insert_after = scope_for_fn_insertion(&body, anchor)?;
let module = ctx.sema.scope(&insert_after).module()?;
let vars_defined_in_body_and_outlive = vars_defined_in_body_and_outlive(ctx, &body);
let ret_ty = body_return_ty(ctx, &body)?;
// FIXME: we compute variables that outlive here just to check `never!` condition
// this requires traversing whole `body` (cheap) and finding all references (expensive)
// maybe we can move this check to `edit` closure somehow?
if stdx::never!(!vars_defined_in_body_and_outlive.is_empty() && !ret_ty.is_unit()) {
// We should not have variables that outlive body if we have expression block
return None;
}
let control_flow = external_control_flow(&body)?;
let target_range = body.text_range();
acc.add(
AssistId("extract_function", crate::AssistKind::RefactorExtract),
"Extract into function",
target_range,
move |builder| {
let params = extracted_function_params(ctx, &body, &vars_used_in_body);
let fun = Function {
name: "fun_name".to_string(),
self_param: self_param.map(|(_, pat)| pat),
params,
control_flow,
ret_ty,
body,
vars_defined_in_body_and_outlive,
};
let new_indent = IndentLevel::from_node(&insert_after);
let old_indent = fun.body.indent_level();
builder.replace(target_range, format_replacement(ctx, &fun, old_indent));
let fn_def = format_function(ctx, module, &fun, old_indent, new_indent);
let insert_offset = insert_after.text_range().end();
builder.insert(insert_offset, fn_def);
},
)
}
fn external_control_flow(body: &FunctionBody) -> Option<ControlFlow> {
let mut ret_expr = None;
let mut try_expr = None;
let mut break_expr = None;
let mut continue_expr = None;
let (syntax, text_range) = match body {
FunctionBody::Expr(expr) => (expr.syntax(), expr.syntax().text_range()),
FunctionBody::Span { parent, text_range } => (parent.syntax(), *text_range),
};
let mut nested_loop = None;
let mut nested_scope = None;
for e in syntax.preorder() {
let e = match e {
WalkEvent::Enter(e) => e,
WalkEvent::Leave(e) => {
if nested_loop.as_ref() == Some(&e) {
nested_loop = None;
}
if nested_scope.as_ref() == Some(&e) {
nested_scope = None;
}
continue;
}
};
if nested_scope.is_some() {
continue;
}
if !text_range.contains_range(e.text_range()) {
continue;
}
match e.kind() {
SyntaxKind::LOOP_EXPR | SyntaxKind::WHILE_EXPR | SyntaxKind::FOR_EXPR => {
if nested_loop.is_none() {
nested_loop = Some(e);
}
}
SyntaxKind::FN
| SyntaxKind::CONST
| SyntaxKind::STATIC
| SyntaxKind::IMPL
| SyntaxKind::MODULE => {
if nested_scope.is_none() {
nested_scope = Some(e);
}
}
SyntaxKind::RETURN_EXPR => {
ret_expr = Some(ast::ReturnExpr::cast(e).unwrap());
}
SyntaxKind::TRY_EXPR => {
try_expr = Some(ast::TryExpr::cast(e).unwrap());
}
SyntaxKind::BREAK_EXPR if nested_loop.is_none() => {
break_expr = Some(ast::BreakExpr::cast(e).unwrap());
}
SyntaxKind::CONTINUE_EXPR if nested_loop.is_none() => {
continue_expr = Some(ast::ContinueExpr::cast(e).unwrap());
}
_ => {}
}
}
if try_expr.is_some() {
// FIXME: support try
return None;
}
let kind = match (ret_expr, break_expr, continue_expr) {
(Some(r), None, None) => match r.expr() {
Some(expr) => Some(FlowKind::ReturnValue(expr)),
None => Some(FlowKind::Return),
},
(Some(_), _, _) => {
mark::hit!(external_control_flow_return_and_bc);
return None;
}
(None, Some(_), Some(_)) => {
mark::hit!(external_control_flow_break_and_continue);
return None;
}
(None, Some(b), None) => match b.expr() {
Some(expr) => Some(FlowKind::BreakValue(expr)),
None => Some(FlowKind::Break),
},
(None, None, Some(_)) => Some(FlowKind::Continue),
(None, None, None) => None,
};
Some(ControlFlow { kind })
}
#[derive(Debug)]
struct Function {
name: String,
self_param: Option<ast::SelfParam>,
params: Vec<Param>,
control_flow: ControlFlow,
ret_ty: RetType,
body: FunctionBody,
vars_defined_in_body_and_outlive: Vec<Local>,
}
#[derive(Debug)]
struct Param {
var: Local,
ty: hir::Type,
has_usages_afterwards: bool,
has_mut_inside_body: bool,
is_copy: bool,
}
#[derive(Debug)]
struct ControlFlow {
kind: Option<FlowKind>,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum ParamKind {
Value,
MutValue,
SharedRef,
MutRef,
}
#[derive(Debug, Eq, PartialEq)]
enum FunType {
Unit,
Single(hir::Type),
Tuple(Vec<hir::Type>),
}
impl Function {
fn return_type(&self, ctx: &AssistContext) -> FunType {
match &self.ret_ty {
RetType::Expr(ty) if ty.is_unit() => FunType::Unit,
RetType::Expr(ty) => FunType::Single(ty.clone()),
RetType::Stmt => match self.vars_defined_in_body_and_outlive.as_slice() {
[] => FunType::Unit,
[var] => FunType::Single(var.ty(ctx.db())),
vars => {
let types = vars.iter().map(|v| v.ty(ctx.db())).collect();
FunType::Tuple(types)
}
},
}
}
}
impl ParamKind {
fn is_ref(&self) -> bool {
matches!(self, ParamKind::SharedRef | ParamKind::MutRef)
}
}
impl Param {
fn kind(&self) -> ParamKind {
match (self.has_usages_afterwards, self.has_mut_inside_body, self.is_copy) {
(true, true, _) => ParamKind::MutRef,
(true, false, false) => ParamKind::SharedRef,
(false, true, _) => ParamKind::MutValue,
(true, false, true) | (false, false, _) => ParamKind::Value,
}
}
fn to_arg(&self, ctx: &AssistContext) -> ast::Expr {
let var = path_expr_from_local(ctx, self.var);
match self.kind() {
ParamKind::Value | ParamKind::MutValue => var,
ParamKind::SharedRef => make::expr_ref(var, false),
ParamKind::MutRef => make::expr_ref(var, true),
}
}
fn to_param(&self, ctx: &AssistContext, module: hir::Module) -> ast::Param {
let var = self.var.name(ctx.db()).unwrap().to_string();
let var_name = make::name(&var);
let pat = match self.kind() {
ParamKind::MutValue => make::ident_mut_pat(var_name),
ParamKind::Value | ParamKind::SharedRef | ParamKind::MutRef => {
make::ident_pat(var_name)
}
};
let ty = make_ty(&self.ty, ctx, module);
let ty = match self.kind() {
ParamKind::Value | ParamKind::MutValue => ty,
ParamKind::SharedRef => make::ty_ref(ty, false),
ParamKind::MutRef => make::ty_ref(ty, true),
};
make::param(pat.into(), ty)
}
}
/// Control flow that is exported from extracted function
///
/// E.g.:
/// ```rust,no_run
/// loop {
/// $0
/// if 42 == 42 {
/// break;
/// }
/// $0
/// }
/// ```
#[derive(Debug, Clone)]
enum FlowKind {
/// Return without value (`return;`)
Return,
/// Return with value (`return $expr;`)
ReturnValue(ast::Expr),
/// Break without value (`return;`)
Break,
/// Break with value (`break $expr;`)
BreakValue(ast::Expr),
/// Continue
Continue,
}
impl FlowKind {
fn make_expr(&self, expr: Option<ast::Expr>) -> ast::Expr {
match self {
FlowKind::Return | FlowKind::ReturnValue(_) => make::expr_return(expr),
FlowKind::Break | FlowKind::BreakValue(_) => make::expr_break(expr),
FlowKind::Continue => {
stdx::always!(expr.is_none(), "continue with value is not possible");
make::expr_continue()
}
}
}
fn expr_ty(&self, ctx: &AssistContext) -> Option<hir::Type> {
match self {
FlowKind::ReturnValue(expr) | FlowKind::BreakValue(expr) => ctx.sema.type_of_expr(expr),
FlowKind::Return | FlowKind::Break | FlowKind::Continue => None,
}
}
}
#[derive(Debug)]
enum RetType {
Expr(hir::Type),
Stmt,
}
impl RetType {
fn is_unit(&self) -> bool {
match self {
RetType::Expr(ty) => ty.is_unit(),
RetType::Stmt => true,
}
}
}
/// Semantically same as `ast::Expr`, but preserves identity when using only part of the Block
#[derive(Debug)]
enum FunctionBody {
Expr(ast::Expr),
Span { parent: ast::BlockExpr, text_range: TextRange },
}
impl FunctionBody {
fn from_whole_node(node: SyntaxNode) -> Option<Self> {
match node.kind() {
PATH_EXPR => None,
BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()).map(Self::Expr),
RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()).map(Self::Expr),
BLOCK_EXPR => ast::BlockExpr::cast(node)
.filter(|it| it.is_standalone())
.map(Into::into)
.map(Self::Expr),
_ => ast::Expr::cast(node).map(Self::Expr),
}
}
fn from_range(node: SyntaxNode, text_range: TextRange) -> Option<FunctionBody> {
let block = ast::BlockExpr::cast(node)?;
Some(Self::Span { parent: block, text_range })
}
fn indent_level(&self) -> IndentLevel {
match &self {
FunctionBody::Expr(expr) => IndentLevel::from_node(expr.syntax()),
FunctionBody::Span { parent, .. } => IndentLevel::from_node(parent.syntax()) + 1,
}
}
fn tail_expr(&self) -> Option<ast::Expr> {
match &self {
FunctionBody::Expr(expr) => Some(expr.clone()),
FunctionBody::Span { parent, text_range } => {
let tail_expr = parent.tail_expr()?;
if text_range.contains_range(tail_expr.syntax().text_range()) {
Some(tail_expr)
} else {
None
}
}
}
}
fn descendants(&self) -> impl Iterator<Item = SyntaxNode> + '_ {
match self {
FunctionBody::Expr(expr) => Either::Right(expr.syntax().descendants()),
FunctionBody::Span { parent, text_range } => Either::Left(
parent
.syntax()
.descendants()
.filter(move |it| text_range.contains_range(it.text_range())),
),
}
}
fn text_range(&self) -> TextRange {
match self {
FunctionBody::Expr(expr) => expr.syntax().text_range(),
FunctionBody::Span { parent: _, text_range } => *text_range,
}
}
fn contains_range(&self, range: TextRange) -> bool {
self.text_range().contains_range(range)
}
fn preceedes_range(&self, range: TextRange) -> bool {
self.text_range().end() <= range.start()
}
fn contains_node(&self, node: &SyntaxNode) -> bool {
self.contains_range(node.text_range())
}
}
impl HasTokenAtOffset for FunctionBody {
fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
match self {
FunctionBody::Expr(expr) => expr.syntax().token_at_offset(offset),
FunctionBody::Span { parent, text_range } => {
match parent.syntax().token_at_offset(offset) {
TokenAtOffset::None => TokenAtOffset::None,
TokenAtOffset::Single(t) => {
if text_range.contains_range(t.text_range()) {
TokenAtOffset::Single(t)
} else {
TokenAtOffset::None
}
}
TokenAtOffset::Between(a, b) => {
match (
text_range.contains_range(a.text_range()),
text_range.contains_range(b.text_range()),
) {
(true, true) => TokenAtOffset::Between(a, b),
(true, false) => TokenAtOffset::Single(a),
(false, true) => TokenAtOffset::Single(b),
(false, false) => TokenAtOffset::None,
}
}
}
}
}
}
}
/// node or token's parent
fn element_to_node(node: SyntaxElement) -> SyntaxNode {
match node {
syntax::NodeOrToken::Node(n) => n,
syntax::NodeOrToken::Token(t) => t.parent(),
}
}
/// Try to guess what user wants to extract
///
/// We have basically have two cases:
/// * We want whole node, like `loop {}`, `2 + 2`, `{ let n = 1; }` exprs.
/// Then we can use `ast::Expr`
/// * We want a few statements for a block. E.g.
/// ```rust,no_run
/// fn foo() -> i32 {
/// let m = 1;
/// $0
/// let n = 2;
/// let k = 3;
/// k + n
/// $0
/// }
/// ```
///
fn extraction_target(node: &SyntaxNode, selection_range: TextRange) -> Option<FunctionBody> {
// we have selected exactly the expr node
// wrap it before anything else
if node.text_range() == selection_range {
let body = FunctionBody::from_whole_node(node.clone());
if body.is_some() {
return body;
}
}
// we have selected a few statements in a block
// so covering_element returns the whole block
if node.kind() == BLOCK_EXPR {
let body = FunctionBody::from_range(node.clone(), selection_range);
if body.is_some() {
return body;
}
}
// we have selected single statement
// `from_whole_node` failed because (let) statement is not and expression
// so we try to expand covering_element to parent and repeat the previous
if let Some(parent) = node.parent() {
if parent.kind() == BLOCK_EXPR {
let body = FunctionBody::from_range(parent, selection_range);
if body.is_some() {
return body;
}
}
}
// select the closest containing expr (both ifs are used)
std::iter::once(node.clone()).chain(node.ancestors()).find_map(FunctionBody::from_whole_node)
}
/// list local variables that are referenced in `body`
fn vars_used_in_body(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> {
// FIXME: currently usages inside macros are not found
body.descendants()
.filter_map(ast::NameRef::cast)
.filter_map(|name_ref| NameRefClass::classify(&ctx.sema, &name_ref))
.map(|name_kind| name_kind.referenced(ctx.db()))
.filter_map(|definition| match definition {
Definition::Local(local) => Some(local),
_ => None,
})
.unique()
.collect()
}
/// find `self` param, that was not defined inside `body`
///
/// It should skip `self` params from impls inside `body`
fn self_param_from_usages(
ctx: &AssistContext,
body: &FunctionBody,
vars_used_in_body: &[Local],
) -> Option<(Local, ast::SelfParam)> {
let mut iter = vars_used_in_body
.iter()
.filter(|var| var.is_self(ctx.db()))
.map(|var| (var, var.source(ctx.db())))
.filter(|(_, src)| is_defined_before(ctx, body, src))
.filter_map(|(&node, src)| match src.value {
Either::Right(it) => Some((node, it)),
Either::Left(_) => {
stdx::never!(false, "Local::is_self returned true, but source is IdentPat");
None
}
});
let self_param = iter.next();
stdx::always!(
iter.next().is_none(),
"body references two different self params, both defined outside"
);
self_param
}
/// find variables that should be extracted as params
///
/// Computes additional info that affects param type and mutability
fn extracted_function_params(
ctx: &AssistContext,
body: &FunctionBody,
vars_used_in_body: &[Local],
) -> Vec<Param> {
vars_used_in_body
.iter()
.filter(|var| !var.is_self(ctx.db()))
.map(|node| (node, node.source(ctx.db())))
.filter(|(_, src)| is_defined_before(ctx, body, src))
.filter_map(|(&node, src)| {
if src.value.is_left() {
Some(node)
} else {
stdx::never!(false, "Local::is_self returned false, but source is SelfParam");
None
}
})
.map(|var| {
let usages = LocalUsages::find(ctx, var);
let ty = var.ty(ctx.db());
let is_copy = ty.is_copy(ctx.db());
Param {
var,
ty,
has_usages_afterwards: has_usages_after_body(&usages, body),
has_mut_inside_body: has_exclusive_usages(ctx, &usages, body),
is_copy,
}
})
.collect()
}
fn has_usages_after_body(usages: &LocalUsages, body: &FunctionBody) -> bool {
usages.iter().any(|reference| body.preceedes_range(reference.range))
}
/// checks if relevant var is used with `&mut` access inside body
fn has_exclusive_usages(ctx: &AssistContext, usages: &LocalUsages, body: &FunctionBody) -> bool {
usages
.iter()
.filter(|reference| body.contains_range(reference.range))
.any(|reference| reference_is_exclusive(reference, body, ctx))
}
/// checks if this reference requires `&mut` access inside body
fn reference_is_exclusive(
reference: &FileReference,
body: &FunctionBody,
ctx: &AssistContext,
) -> bool {
// we directly modify variable with set: `n = 0`, `n += 1`
if reference.access == Some(ReferenceAccess::Write) {
return true;
}
// we take `&mut` reference to variable: `&mut v`
let path = match path_element_of_reference(body, reference) {
Some(path) => path,
None => return false,
};
expr_require_exclusive_access(ctx, &path).unwrap_or(false)
}
/// checks if this expr requires `&mut` access, recurses on field access
fn expr_require_exclusive_access(ctx: &AssistContext, expr: &ast::Expr) -> Option<bool> {
let parent = expr.syntax().parent()?;
if let Some(bin_expr) = ast::BinExpr::cast(parent.clone()) {
if bin_expr.op_kind()?.is_assignment() {
return Some(bin_expr.lhs()?.syntax() == expr.syntax());
}
return Some(false);
}
if let Some(ref_expr) = ast::RefExpr::cast(parent.clone()) {
return Some(ref_expr.mut_token().is_some());
}
if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
let func = ctx.sema.resolve_method_call(&method_call)?;
let self_param = func.self_param(ctx.db())?;
let access = self_param.access(ctx.db());
return Some(matches!(access, hir::Access::Exclusive));
}
if let Some(field) = ast::FieldExpr::cast(parent) {
return expr_require_exclusive_access(ctx, &field.into());
}
Some(false)
}
/// Container of local varaible usages
///
/// Semanticall same as `UsageSearchResult`, but provides more convenient interface
struct LocalUsages(ide_db::search::UsageSearchResult);
impl LocalUsages {
fn find(ctx: &AssistContext, var: Local) -> Self {
Self(
Definition::Local(var)
.usages(&ctx.sema)
.in_scope(SearchScope::single_file(ctx.frange.file_id))
.all(),
)
}
fn iter(&self) -> impl Iterator<Item = &FileReference> + '_ {
self.0.iter().flat_map(|(_, rs)| rs.iter())
}
}
trait HasTokenAtOffset {
fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>;
}
impl HasTokenAtOffset for SyntaxNode {
fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
SyntaxNode::token_at_offset(&self, offset)
}
}
/// find relevant `ast::PathExpr` for reference
///
/// # Preconditions
///
/// `node` must cover `reference`, that is `node.text_range().contains_range(reference.range)`
fn path_element_of_reference(
node: &dyn HasTokenAtOffset,
reference: &FileReference,
) -> Option<ast::Expr> {
let token = node.token_at_offset(reference.range.start()).right_biased().or_else(|| {
stdx::never!(false, "cannot find token at variable usage: {:?}", reference);
None
})?;
let path = token.ancestors().find_map(ast::Expr::cast).or_else(|| {
stdx::never!(false, "cannot find path parent of variable usage: {:?}", token);
None
})?;
stdx::always!(matches!(path, ast::Expr::PathExpr(_)));
Some(path)
}
/// list local variables defined inside `body`
fn vars_defined_in_body(body: &FunctionBody, ctx: &AssistContext) -> Vec<Local> {
// FIXME: this doesn't work well with macros
// see https://github.com/rust-analyzer/rust-analyzer/pull/7535#discussion_r570048550
body.descendants()
.filter_map(ast::IdentPat::cast)
.filter_map(|let_stmt| ctx.sema.to_def(&let_stmt))
.unique()
.collect()
}
/// list local variables defined inside `body` that should be returned from extracted function
fn vars_defined_in_body_and_outlive(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> {
let mut vars_defined_in_body = vars_defined_in_body(&body, ctx);
vars_defined_in_body.retain(|var| var_outlives_body(ctx, body, var));
vars_defined_in_body
}
/// checks if the relevant local was defined before(outside of) body
fn is_defined_before(
ctx: &AssistContext,
body: &FunctionBody,
src: &hir::InFile<Either<ast::IdentPat, ast::SelfParam>>,
) -> bool {
src.file_id.original_file(ctx.db()) == ctx.frange.file_id
&& !body.contains_node(&either_syntax(&src.value))
}
fn either_syntax(value: &Either<ast::IdentPat, ast::SelfParam>) -> &SyntaxNode {
match value {
Either::Left(pat) => pat.syntax(),
Either::Right(it) => it.syntax(),
}
}
/// checks if local variable is used after(outside of) body
fn var_outlives_body(ctx: &AssistContext, body: &FunctionBody, var: &Local) -> bool {
let usages = LocalUsages::find(ctx, *var);
let has_usages = usages.iter().any(|reference| body.preceedes_range(reference.range));
has_usages
}
fn body_return_ty(ctx: &AssistContext, body: &FunctionBody) -> Option<RetType> {
match body.tail_expr() {
Some(expr) => {
let ty = ctx.sema.type_of_expr(&expr)?;
Some(RetType::Expr(ty))
}
None => Some(RetType::Stmt),
}
}
/// Where to put extracted function definition
#[derive(Debug)]
enum Anchor {
/// Extract free function and put right after current top-level function
Freestanding,
/// Extract method and put right after current function in the impl-block
Method,
}
/// find where to put extracted function definition
///
/// Function should be put right after returned node
fn scope_for_fn_insertion(body: &FunctionBody, anchor: Anchor) -> Option<SyntaxNode> {
match body {
FunctionBody::Expr(e) => scope_for_fn_insertion_node(e.syntax(), anchor),
FunctionBody::Span { parent, .. } => scope_for_fn_insertion_node(parent.syntax(), anchor),
}
}
fn scope_for_fn_insertion_node(node: &SyntaxNode, anchor: Anchor) -> Option<SyntaxNode> {
let mut ancestors = node.ancestors().peekable();
let mut last_ancestor = None;
while let Some(next_ancestor) = ancestors.next() {
match next_ancestor.kind() {
SyntaxKind::SOURCE_FILE => break,
SyntaxKind::ITEM_LIST => {
if !matches!(anchor, Anchor::Freestanding) {
continue;
}
if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::MODULE) {
break;
}
}
SyntaxKind::ASSOC_ITEM_LIST => {
if !matches!(anchor, Anchor::Method) {
continue;
}
if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::IMPL) {
break;
}
}
_ => {}
}
last_ancestor = Some(next_ancestor);
}
last_ancestor
}
fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel) -> String {
let ret_ty = fun.return_type(ctx);
let args = fun.params.iter().map(|param| param.to_arg(ctx));
let args = make::arg_list(args);
let call_expr = if fun.self_param.is_some() {
let self_arg = make::expr_path(make_path_from_text("self"));
make::expr_method_call(self_arg, &fun.name, args)
} else {
let func = make::expr_path(make_path_from_text(&fun.name));
make::expr_call(func, args)
};
let handler = FlowHandler::from_ret_ty(fun, &ret_ty);
let expr = handler.make_expr(call_expr).indent(indent);
let mut buf = String::new();
match fun.vars_defined_in_body_and_outlive.as_slice() {
[] => {}
[var] => format_to!(buf, "let {} = ", var.name(ctx.db()).unwrap()),
[v0, vs @ ..] => {
buf.push_str("let (");
format_to!(buf, "{}", v0.name(ctx.db()).unwrap());
for var in vs {
format_to!(buf, ", {}", var.name(ctx.db()).unwrap());
}
buf.push_str(") = ");
}
}
format_to!(buf, "{}", expr);
if fun.ret_ty.is_unit()
&& (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like())
{
buf.push(';');
}
buf
}
enum FlowHandler {
None,
If { action: FlowKind },
IfOption { action: FlowKind },
MatchOption { none: FlowKind },
MatchResult { err: FlowKind },
}
impl FlowHandler {
fn from_ret_ty(fun: &Function, ret_ty: &FunType) -> FlowHandler {
match &fun.control_flow.kind {
None => FlowHandler::None,
Some(flow_kind) => {
let action = flow_kind.clone();
if *ret_ty == FunType::Unit {
match flow_kind {
FlowKind::Return | FlowKind::Break | FlowKind::Continue => {
FlowHandler::If { action }
}
FlowKind::ReturnValue(_) | FlowKind::BreakValue(_) => {
FlowHandler::IfOption { action }
}
}
} else {
match flow_kind {
FlowKind::Return | FlowKind::Break | FlowKind::Continue => {
FlowHandler::MatchOption { none: action }
}
FlowKind::ReturnValue(_) | FlowKind::BreakValue(_) => {
FlowHandler::MatchResult { err: action }
}
}
}
}
}
}
fn make_expr(&self, call_expr: ast::Expr) -> ast::Expr {
match self {
FlowHandler::None => call_expr,
FlowHandler::If { action } => {
let action = action.make_expr(None);
let stmt = make::expr_stmt(action);
let block = make::block_expr(iter::once(stmt.into()), None);
let condition = make::condition(call_expr, None);
make::expr_if(condition, block, None)
}
FlowHandler::IfOption { action } => {
let path = make_path_from_text("Some");
let value_pat = make::ident_pat(make::name("value"));
let pattern = make::tuple_struct_pat(path, iter::once(value_pat.into()));
let cond = make::condition(call_expr, Some(pattern.into()));
let value = make::expr_path(make_path_from_text("value"));
let action_expr = action.make_expr(Some(value));
let action_stmt = make::expr_stmt(action_expr);
let then = make::block_expr(iter::once(action_stmt.into()), None);
make::expr_if(cond, then, None)
}
FlowHandler::MatchOption { none } => {
let some_name = "value";
let some_arm = {
let path = make_path_from_text("Some");
let value_pat = make::ident_pat(make::name(some_name));
let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
let value = make::expr_path(make_path_from_text(some_name));
make::match_arm(iter::once(pat.into()), value)
};
let none_arm = {
let path = make_path_from_text("None");
let pat = make::path_pat(path);
make::match_arm(iter::once(pat), none.make_expr(None))
};
let arms = make::match_arm_list(vec![some_arm, none_arm]);
make::expr_match(call_expr, arms)
}
FlowHandler::MatchResult { err } => {
let ok_name = "value";
let err_name = "value";
let ok_arm = {
let path = make_path_from_text("Ok");
let value_pat = make::ident_pat(make::name(ok_name));
let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
let value = make::expr_path(make_path_from_text(ok_name));
make::match_arm(iter::once(pat.into()), value)
};
let err_arm = {
let path = make_path_from_text("Err");
let value_pat = make::ident_pat(make::name(err_name));
let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
let value = make::expr_path(make_path_from_text(err_name));
make::match_arm(iter::once(pat.into()), err.make_expr(Some(value)))
};
let arms = make::match_arm_list(vec![ok_arm, err_arm]);
make::expr_match(call_expr, arms)
}
}
}
}
fn make_path_from_text(text: &str) -> ast::Path {
make::path_unqualified(make::path_segment(make::name_ref(text)))
}
fn path_expr_from_local(ctx: &AssistContext, var: Local) -> ast::Expr {
let name = var.name(ctx.db()).unwrap().to_string();
make::expr_path(make_path_from_text(&name))
}
fn format_function(
ctx: &AssistContext,
module: hir::Module,
fun: &Function,
old_indent: IndentLevel,
new_indent: IndentLevel,
) -> String {
let mut fn_def = String::new();
let params = make_param_list(ctx, module, fun);
let ret_ty = make_ret_ty(ctx, module, fun);
let body = make_body(ctx, old_indent, new_indent, fun);
format_to!(fn_def, "\n\n{}fn $0{}{}", new_indent, fun.name, params);
if let Some(ret_ty) = ret_ty {
format_to!(fn_def, " {}", ret_ty);
}
format_to!(fn_def, " {}", body);
fn_def
}
fn make_param_list(ctx: &AssistContext, module: hir::Module, fun: &Function) -> ast::ParamList {
let self_param = fun.self_param.clone();
let params = fun.params.iter().map(|param| param.to_param(ctx, module));
make::param_list(self_param, params)
}
impl FunType {
fn make_ty(&self, ctx: &AssistContext, module: hir::Module) -> ast::Type {
match self {
FunType::Unit => make::ty_unit(),
FunType::Single(ty) => make_ty(ty, ctx, module),
FunType::Tuple(types) => match types.as_slice() {
[] => {
stdx::never!("tuple type with 0 elements");
make::ty_unit()
}
[ty] => {
stdx::never!("tuple type with 1 element");
make_ty(ty, ctx, module)
}
types => {
let types = types.iter().map(|ty| make_ty(ty, ctx, module));
make::ty_tuple(types)
}
},
}
}
}
fn make_ret_ty(ctx: &AssistContext, module: hir::Module, fun: &Function) -> Option<ast::RetType> {
let ty = fun.return_type(ctx);
let handler = FlowHandler::from_ret_ty(fun, &ty);
let ret_ty = match &handler {
FlowHandler::None => {
if matches!(ty, FunType::Unit) {
return None;
}
ty.make_ty(ctx, module)
}
FlowHandler::If { .. } => make::ty("bool"),
FlowHandler::IfOption { action } => {
let handler_ty = action
.expr_ty(ctx)
.map(|ty| make_ty(&ty, ctx, module))
.unwrap_or_else(make::ty_unit);
make::ty_generic(make::name_ref("Option"), iter::once(handler_ty))
}
FlowHandler::MatchOption { .. } => {
make::ty_generic(make::name_ref("Option"), iter::once(ty.make_ty(ctx, module)))
}
FlowHandler::MatchResult { err } => {
let handler_ty =
err.expr_ty(ctx).map(|ty| make_ty(&ty, ctx, module)).unwrap_or_else(make::ty_unit);
make::ty_generic(make::name_ref("Result"), vec![ty.make_ty(ctx, module), handler_ty])
}
};
Some(make::ret_type(ret_ty))
}
fn make_body(
ctx: &AssistContext,
old_indent: IndentLevel,
new_indent: IndentLevel,
fun: &Function,
) -> ast::BlockExpr {
let ret_ty = fun.return_type(ctx);
let handler = FlowHandler::from_ret_ty(fun, &ret_ty);
let block = match &fun.body {
FunctionBody::Expr(expr) => {
let expr = rewrite_body_segment(ctx, &fun.params, &handler, expr.syntax());
let expr = ast::Expr::cast(expr).unwrap();
let expr = expr.dedent(old_indent).indent(IndentLevel(1));
make::block_expr(Vec::new(), Some(expr))
}
FunctionBody::Span { parent, text_range } => {
let mut elements: Vec<_> = parent
.syntax()
.children()
.filter(|it| text_range.contains_range(it.text_range()))
.map(|it| rewrite_body_segment(ctx, &fun.params, &handler, &it))
.collect();
let mut tail_expr = match elements.pop() {
Some(node) => ast::Expr::cast(node.clone()).or_else(|| {
elements.push(node);
None
}),
None => None,
};
if tail_expr.is_none() {
match fun.vars_defined_in_body_and_outlive.as_slice() {
[] => {}
[var] => {
tail_expr = Some(path_expr_from_local(ctx, *var));
}
vars => {
let exprs = vars.iter().map(|var| path_expr_from_local(ctx, *var));
let expr = make::expr_tuple(exprs);
tail_expr = Some(expr);
}
}
}
let elements = elements.into_iter().filter_map(|node| match ast::Stmt::cast(node) {
Some(stmt) => Some(stmt),
None => {
stdx::never!("block contains non-statement");
None
}
});
let body_indent = IndentLevel(1);
let elements = elements.map(|stmt| stmt.dedent(old_indent).indent(body_indent));
let tail_expr = tail_expr.map(|expr| expr.dedent(old_indent).indent(body_indent));
make::block_expr(elements, tail_expr)
}
};
let block = match &handler {
FlowHandler::None => block,
FlowHandler::If { .. } => {
let lit_false = ast::Literal::cast(make::tokens::literal("false").parent()).unwrap();
with_tail_expr(block, lit_false.into())
}
FlowHandler::IfOption { .. } => {
let none = make::expr_path(make_path_from_text("None"));
with_tail_expr(block, none)
}
FlowHandler::MatchOption { .. } => map_tail_expr(block, |tail_expr| {
let some = make::expr_path(make_path_from_text("Some"));
let args = make::arg_list(iter::once(tail_expr));
make::expr_call(some, args)
}),
FlowHandler::MatchResult { .. } => map_tail_expr(block, |tail_expr| {
let some = make::expr_path(make_path_from_text("Ok"));
let args = make::arg_list(iter::once(tail_expr));
make::expr_call(some, args)
}),
};
block.indent(new_indent)
}
fn map_tail_expr(block: ast::BlockExpr, f: impl FnOnce(ast::Expr) -> ast::Expr) -> ast::BlockExpr {
let tail_expr = match block.tail_expr() {
Some(tail_expr) => tail_expr,
None => return block,
};
make::block_expr(block.statements(), Some(f(tail_expr)))
}
fn with_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
let stmt_tail = block.tail_expr().map(|expr| make::expr_stmt(expr).into());
let stmts = block.statements().chain(stmt_tail);
make::block_expr(stmts, Some(tail_expr))
}
fn format_type(ty: &hir::Type, ctx: &AssistContext, module: hir::Module) -> String {
ty.display_source_code(ctx.db(), module.into()).ok().unwrap_or_else(|| "()".to_string())
}
fn make_ty(ty: &hir::Type, ctx: &AssistContext, module: hir::Module) -> ast::Type {
let ty_str = format_type(ty, ctx, module);
make::ty(&ty_str)
}
fn rewrite_body_segment(
ctx: &AssistContext,
params: &[Param],
handler: &FlowHandler,
syntax: &SyntaxNode,
) -> SyntaxNode {
let syntax = fix_param_usages(ctx, params, syntax);
update_external_control_flow(handler, &syntax)
}
/// change all usages to account for added `&`/`&mut` for some params
fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode {
let mut rewriter = SyntaxRewriter::default();
for param in params {
if !param.kind().is_ref() {
continue;
}
let usages = LocalUsages::find(ctx, param.var);
let usages = usages
.iter()
.filter(|reference| syntax.text_range().contains_range(reference.range))
.filter_map(|reference| path_element_of_reference(syntax, reference));
for path in usages {
match path.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
Some(ast::Expr::MethodCallExpr(_)) | Some(ast::Expr::FieldExpr(_)) => {
// do nothing
}
Some(ast::Expr::RefExpr(node))
if param.kind() == ParamKind::MutRef && node.mut_token().is_some() =>
{
rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
}
Some(ast::Expr::RefExpr(node))
if param.kind() == ParamKind::SharedRef && node.mut_token().is_none() =>
{
rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
}
Some(_) | None => {
rewriter.replace_ast(&path, &make::expr_prefix(T![*], path.clone()));
}
};
}
}
rewriter.rewrite(syntax)
}
fn update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode) -> SyntaxNode {
let mut rewriter = SyntaxRewriter::default();
let mut nested_loop = None;
let mut nested_scope = None;
for event in syntax.preorder() {
let node = match event {
WalkEvent::Enter(e) => {
match e.kind() {
SyntaxKind::LOOP_EXPR | SyntaxKind::WHILE_EXPR | SyntaxKind::FOR_EXPR => {
if nested_loop.is_none() {
nested_loop = Some(e.clone());
}
}
SyntaxKind::FN
| SyntaxKind::CONST
| SyntaxKind::STATIC
| SyntaxKind::IMPL
| SyntaxKind::MODULE => {
if nested_scope.is_none() {
nested_scope = Some(e.clone());
}
}
_ => {}
}
e
}
WalkEvent::Leave(e) => {
if nested_loop.as_ref() == Some(&e) {
nested_loop = None;
}
if nested_scope.as_ref() == Some(&e) {
nested_scope = None;
}
continue;
}
};
if nested_scope.is_some() {
continue;
}
let expr = match ast::Expr::cast(node) {
Some(e) => e,
None => continue,
};
match expr {
ast::Expr::ReturnExpr(return_expr) if nested_scope.is_none() => {
let expr = return_expr.expr();
if let Some(replacement) = make_rewritten_flow(handler, expr) {
rewriter.replace_ast(&return_expr.into(), &replacement);
}
}
ast::Expr::BreakExpr(break_expr) if nested_loop.is_none() => {
let expr = break_expr.expr();
if let Some(replacement) = make_rewritten_flow(handler, expr) {
rewriter.replace_ast(&break_expr.into(), &replacement);
}
}
ast::Expr::ContinueExpr(continue_expr) if nested_loop.is_none() => {
if let Some(replacement) = make_rewritten_flow(handler, None) {
rewriter.replace_ast(&continue_expr.into(), &replacement);
}
}
_ => {
// do nothing
}
}
}
rewriter.rewrite(syntax)
}
fn make_rewritten_flow(handler: &FlowHandler, arg_expr: Option<ast::Expr>) -> Option<ast::Expr> {
let value = match handler {
FlowHandler::None => return None,
FlowHandler::If { .. } => {
ast::Literal::cast(make::tokens::literal("true").parent()).unwrap().into()
}
FlowHandler::IfOption { .. } => {
let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
let args = make::arg_list(iter::once(expr));
make::expr_call(make::expr_path(make_path_from_text("Some")), args)
}
FlowHandler::MatchOption { .. } => make::expr_path(make_path_from_text("None")),
FlowHandler::MatchResult { .. } => {
let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
let args = make::arg_list(iter::once(expr));
make::expr_call(make::expr_path(make_path_from_text("Err")), args)
}
};
Some(make::expr_return(Some(value)))
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
#[test]
fn no_args_from_binary_expr() {
check_assist(
extract_function,
r#"
fn foo() {
foo($01 + 1$0);
}"#,
r#"
fn foo() {
foo(fun_name());
}
fn $0fun_name() -> i32 {
1 + 1
}"#,
);
}
#[test]
fn no_args_from_binary_expr_in_module() {
check_assist(
extract_function,
r#"
mod bar {
fn foo() {
foo($01 + 1$0);
}
}"#,
r#"
mod bar {
fn foo() {
foo(fun_name());
}
fn $0fun_name() -> i32 {
1 + 1
}
}"#,
);
}
#[test]
fn no_args_from_binary_expr_indented() {
check_assist(
extract_function,
r#"
fn foo() {
$0{ 1 + 1 }$0;
}"#,
r#"
fn foo() {
fun_name();
}
fn $0fun_name() -> i32 {
{ 1 + 1 }
}"#,
);
}
#[test]
fn no_args_from_stmt_with_last_expr() {
check_assist(
extract_function,
r#"
fn foo() -> i32 {
let k = 1;
$0let m = 1;
m + 1$0
}"#,
r#"
fn foo() -> i32 {
let k = 1;
fun_name()
}
fn $0fun_name() -> i32 {
let m = 1;
m + 1
}"#,
);
}
#[test]
fn no_args_from_stmt_unit() {
check_assist(
extract_function,
r#"
fn foo() {
let k = 3;
$0let m = 1;
let n = m + 1;$0
let g = 5;
}"#,
r#"
fn foo() {
let k = 3;
fun_name();
let g = 5;
}
fn $0fun_name() {
let m = 1;
let n = m + 1;
}"#,
);
}
#[test]
fn no_args_if() {
check_assist(
extract_function,
r#"
fn foo() {
$0if true { }$0
}"#,
r#"
fn foo() {
fun_name();
}
fn $0fun_name() {
if true { }
}"#,
);
}
#[test]
fn no_args_if_else() {
check_assist(
extract_function,
r#"
fn foo() -> i32 {
$0if true { 1 } else { 2 }$0
}"#,
r#"
fn foo() -> i32 {
fun_name()
}
fn $0fun_name() -> i32 {
if true { 1 } else { 2 }
}"#,
);
}
#[test]
fn no_args_if_let_else() {
check_assist(
extract_function,
r#"
fn foo() -> i32 {
$0if let true = false { 1 } else { 2 }$0
}"#,
r#"
fn foo() -> i32 {
fun_name()
}
fn $0fun_name() -> i32 {
if let true = false { 1 } else { 2 }
}"#,
);
}
#[test]
fn no_args_match() {
check_assist(
extract_function,
r#"
fn foo() -> i32 {
$0match true {
true => 1,
false => 2,
}$0
}"#,
r#"
fn foo() -> i32 {
fun_name()
}
fn $0fun_name() -> i32 {
match true {
true => 1,
false => 2,
}
}"#,
);
}
#[test]
fn no_args_while() {
check_assist(
extract_function,
r#"
fn foo() {
$0while true { }$0
}"#,
r#"
fn foo() {
fun_name();
}
fn $0fun_name() {
while true { }
}"#,
);
}
#[test]
fn no_args_for() {
check_assist(
extract_function,
r#"
fn foo() {
$0for v in &[0, 1] { }$0
}"#,
r#"
fn foo() {
fun_name();
}
fn $0fun_name() {
for v in &[0, 1] { }
}"#,
);
}
#[test]
fn no_args_from_loop_unit() {
check_assist(
extract_function,
r#"
fn foo() {
$0loop {
let m = 1;
}$0
}"#,
r#"
fn foo() {
fun_name()
}
fn $0fun_name() -> ! {
loop {
let m = 1;
}
}"#,
);
}
#[test]
fn no_args_from_loop_with_return() {
check_assist(
extract_function,
r#"
fn foo() {
let v = $0loop {
let m = 1;
break m;
}$0;
}"#,
r#"
fn foo() {
let v = fun_name();
}
fn $0fun_name() -> i32 {
loop {
let m = 1;
break m;
}
}"#,
);
}
#[test]
fn no_args_from_match() {
check_assist(
extract_function,
r#"
fn foo() {
let v: i32 = $0match Some(1) {
Some(x) => x,
None => 0,
}$0;
}"#,
r#"
fn foo() {
let v: i32 = fun_name();
}
fn $0fun_name() -> i32 {
match Some(1) {
Some(x) => x,
None => 0,
}
}"#,
);
}
#[test]
fn argument_form_expr() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
let n = 2;
$0n+2$0
}",
r"
fn foo() -> u32 {
let n = 2;
fun_name(n)
}
fn $0fun_name(n: u32) -> u32 {
n+2
}",
)
}
#[test]
fn argument_used_twice_form_expr() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
let n = 2;
$0n+n$0
}",
r"
fn foo() -> u32 {
let n = 2;
fun_name(n)
}
fn $0fun_name(n: u32) -> u32 {
n+n
}",
)
}
#[test]
fn two_arguments_form_expr() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
let n = 2;
let m = 3;
$0n+n*m$0
}",
r"
fn foo() -> u32 {
let n = 2;
let m = 3;
fun_name(n, m)
}
fn $0fun_name(n: u32, m: u32) -> u32 {
n+n*m
}",
)
}
#[test]
fn argument_and_locals() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
let n = 2;
$0let m = 1;
n + m$0
}",
r"
fn foo() -> u32 {
let n = 2;
fun_name(n)
}
fn $0fun_name(n: u32) -> u32 {
let m = 1;
n + m
}",
)
}
#[test]
fn in_comment_is_not_applicable() {
mark::check!(extract_function_in_comment_is_not_applicable);
check_assist_not_applicable(extract_function, r"fn main() { 1 + /* $0comment$0 */ 1; }");
}
#[test]
fn part_of_expr_stmt() {
check_assist(
extract_function,
"
fn foo() {
$01$0 + 1;
}",
"
fn foo() {
fun_name() + 1;
}
fn $0fun_name() -> i32 {
1
}",
);
}
#[test]
fn function_expr() {
check_assist(
extract_function,
r#"
fn foo() {
$0bar(1 + 1)$0
}"#,
r#"
fn foo() {
fun_name();
}
fn $0fun_name() {
bar(1 + 1)
}"#,
)
}
#[test]
fn extract_from_nested() {
check_assist(
extract_function,
r"
fn main() {
let x = true;
let tuple = match x {
true => ($02 + 2$0, true)
_ => (0, false)
};
}",
r"
fn main() {
let x = true;
let tuple = match x {
true => (fun_name(), true)
_ => (0, false)
};
}
fn $0fun_name() -> i32 {
2 + 2
}",
);
}
#[test]
fn param_from_closure() {
check_assist(
extract_function,
r"
fn main() {
let lambda = |x: u32| $0x * 2$0;
}",
r"
fn main() {
let lambda = |x: u32| fun_name(x);
}
fn $0fun_name(x: u32) -> u32 {
x * 2
}",
);
}
#[test]
fn extract_return_stmt() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
$0return 2 + 2$0;
}",
r"
fn foo() -> u32 {
return fun_name();
}
fn $0fun_name() -> u32 {
2 + 2
}",
);
}
#[test]
fn does_not_add_extra_whitespace() {
check_assist(
extract_function,
r"
fn foo() -> u32 {
$0return 2 + 2$0;
}",
r"
fn foo() -> u32 {
return fun_name();
}
fn $0fun_name() -> u32 {
2 + 2
}",
);
}
#[test]
fn break_stmt() {
check_assist(
extract_function,
r"
fn main() {
let result = loop {
$0break 2 + 2$0;
};
}",
r"
fn main() {
let result = loop {
break fun_name();
};
}
fn $0fun_name() -> i32 {
2 + 2
}",
);
}
#[test]
fn extract_cast() {
check_assist(
extract_function,
r"
fn main() {
let v = $00f32 as u32$0;
}",
r"
fn main() {
let v = fun_name();
}
fn $0fun_name() -> u32 {
0f32 as u32
}",
);
}
#[test]
fn return_not_applicable() {
check_assist_not_applicable(extract_function, r"fn foo() { $0return$0; } ");
}
#[test]
fn method_to_freestanding() {
check_assist(
extract_function,
r"
struct S;
impl S {
fn foo(&self) -> i32 {
$01+1$0
}
}",
r"
struct S;
impl S {
fn foo(&self) -> i32 {
fun_name()
}
}
fn $0fun_name() -> i32 {
1+1
}",
);
}
#[test]
fn method_with_reference() {
check_assist(
extract_function,
r"
struct S { f: i32 };
impl S {
fn foo(&self) -> i32 {
$01+self.f$0
}
}",
r"
struct S { f: i32 };
impl S {
fn foo(&self) -> i32 {
self.fun_name()
}
fn $0fun_name(&self) -> i32 {
1+self.f
}
}",
);
}
#[test]
fn method_with_mut() {
check_assist(
extract_function,
r"
struct S { f: i32 };
impl S {
fn foo(&mut self) {
$0self.f += 1;$0
}
}",
r"
struct S { f: i32 };
impl S {
fn foo(&mut self) {
self.fun_name();
}
fn $0fun_name(&mut self) {
self.f += 1;
}
}",
);
}
#[test]
fn variable_defined_inside_and_used_after_no_ret() {
check_assist(
extract_function,
r"
fn foo() {
let n = 1;
$0let k = n * n;$0
let m = k + 1;
}",
r"
fn foo() {
let n = 1;
let k = fun_name(n);
let m = k + 1;
}
fn $0fun_name(n: i32) -> i32 {
let k = n * n;
k
}",
);
}
#[test]
fn two_variables_defined_inside_and_used_after_no_ret() {
check_assist(
extract_function,
r"
fn foo() {
let n = 1;
$0let k = n * n;
let m = k + 2;$0
let h = k + m;
}",
r"
fn foo() {
let n = 1;
let (k, m) = fun_name(n);
let h = k + m;
}
fn $0fun_name(n: i32) -> (i32, i32) {
let k = n * n;
let m = k + 2;
(k, m)
}",
);
}
#[test]
fn nontrivial_patterns_define_variables() {
check_assist(
extract_function,
r"
struct Counter(i32);
fn foo() {
$0let Counter(n) = Counter(0);$0
let m = n;
}",
r"
struct Counter(i32);
fn foo() {
let n = fun_name();
let m = n;
}
fn $0fun_name() -> i32 {
let Counter(n) = Counter(0);
n
}",
);
}
#[test]
fn struct_with_two_fields_pattern_define_variables() {
check_assist(
extract_function,
r"
struct Counter { n: i32, m: i32 };
fn foo() {
$0let Counter { n, m: k } = Counter { n: 1, m: 2 };$0
let h = n + k;
}",
r"
struct Counter { n: i32, m: i32 };
fn foo() {
let (n, k) = fun_name();
let h = n + k;
}
fn $0fun_name() -> (i32, i32) {
let Counter { n, m: k } = Counter { n: 1, m: 2 };
(n, k)
}",
);
}
#[test]
fn mut_var_from_outer_scope() {
check_assist(
extract_function,
r"
fn foo() {
let mut n = 1;
$0n += 1;$0
let m = n + 1;
}",
r"
fn foo() {
let mut n = 1;
fun_name(&mut n);
let m = n + 1;
}
fn $0fun_name(n: &mut i32) {
*n += 1;
}",
);
}
#[test]
fn mut_field_from_outer_scope() {
check_assist(
extract_function,
r"
struct C { n: i32 }
fn foo() {
let mut c = C { n: 0 };
$0c.n += 1;$0
let m = c.n + 1;
}",
r"
struct C { n: i32 }
fn foo() {
let mut c = C { n: 0 };
fun_name(&mut c);
let m = c.n + 1;
}
fn $0fun_name(c: &mut C) {
c.n += 1;
}",
);
}
#[test]
fn mut_nested_field_from_outer_scope() {
check_assist(
extract_function,
r"
struct P { n: i32}
struct C { p: P }
fn foo() {
let mut c = C { p: P { n: 0 } };
let mut v = C { p: P { n: 0 } };
let u = C { p: P { n: 0 } };
$0c.p.n += u.p.n;
let r = &mut v.p.n;$0
let m = c.p.n + v.p.n + u.p.n;
}",
r"
struct P { n: i32}
struct C { p: P }
fn foo() {
let mut c = C { p: P { n: 0 } };
let mut v = C { p: P { n: 0 } };
let u = C { p: P { n: 0 } };
fun_name(&mut c, &u, &mut v);
let m = c.p.n + v.p.n + u.p.n;
}
fn $0fun_name(c: &mut C, u: &C, v: &mut C) {
c.p.n += u.p.n;
let r = &mut v.p.n;
}",
);
}
#[test]
fn mut_param_many_usages_stmt() {
check_assist(
extract_function,
r"
fn bar(k: i32) {}
trait I: Copy {
fn succ(&self) -> Self;
fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
}
impl I for i32 {
fn succ(&self) -> Self { *self + 1 }
}
fn foo() {
let mut n = 1;
$0n += n;
bar(n);
bar(n+1);
bar(n*n);
bar(&n);
n.inc();
let v = &mut n;
*v = v.succ();
n.succ();$0
let m = n + 1;
}",
r"
fn bar(k: i32) {}
trait I: Copy {
fn succ(&self) -> Self;
fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
}
impl I for i32 {
fn succ(&self) -> Self { *self + 1 }
}
fn foo() {
let mut n = 1;
fun_name(&mut n);
let m = n + 1;
}
fn $0fun_name(n: &mut i32) {
*n += *n;
bar(*n);
bar(*n+1);
bar(*n**n);
bar(&*n);
n.inc();
let v = n;
*v = v.succ();
n.succ();
}",
);
}
#[test]
fn mut_param_many_usages_expr() {
check_assist(
extract_function,
r"
fn bar(k: i32) {}
trait I: Copy {
fn succ(&self) -> Self;
fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
}
impl I for i32 {
fn succ(&self) -> Self { *self + 1 }
}
fn foo() {
let mut n = 1;
$0{
n += n;
bar(n);
bar(n+1);
bar(n*n);
bar(&n);
n.inc();
let v = &mut n;
*v = v.succ();
n.succ();
}$0
let m = n + 1;
}",
r"
fn bar(k: i32) {}
trait I: Copy {
fn succ(&self) -> Self;
fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
}
impl I for i32 {
fn succ(&self) -> Self { *self + 1 }
}
fn foo() {
let mut n = 1;
fun_name(&mut n);
let m = n + 1;
}
fn $0fun_name(n: &mut i32) {
{
*n += *n;
bar(*n);
bar(*n+1);
bar(*n**n);
bar(&*n);
n.inc();
let v = n;
*v = v.succ();
n.succ();
}
}",
);
}
#[test]
fn mut_param_by_value() {
check_assist(
extract_function,
r"
fn foo() {
let mut n = 1;
$0n += 1;$0
}",
r"
fn foo() {
let mut n = 1;
fun_name(n);
}
fn $0fun_name(mut n: i32) {
n += 1;
}",
);
}
#[test]
fn mut_param_because_of_mut_ref() {
check_assist(
extract_function,
r"
fn foo() {
let mut n = 1;
$0let v = &mut n;
*v += 1;$0
let k = n;
}",
r"
fn foo() {
let mut n = 1;
fun_name(&mut n);
let k = n;
}
fn $0fun_name(n: &mut i32) {
let v = n;
*v += 1;
}",
);
}
#[test]
fn mut_param_by_value_because_of_mut_ref() {
check_assist(
extract_function,
r"
fn foo() {
let mut n = 1;
$0let v = &mut n;
*v += 1;$0
}",
r"
fn foo() {
let mut n = 1;
fun_name(n);
}
fn $0fun_name(mut n: i32) {
let v = &mut n;
*v += 1;
}",
);
}
#[test]
fn mut_method_call() {
check_assist(
extract_function,
r"
trait I {
fn inc(&mut self);
}
impl I for i32 {
fn inc(&mut self) { *self += 1 }
}
fn foo() {
let mut n = 1;
$0n.inc();$0
}",
r"
trait I {
fn inc(&mut self);
}
impl I for i32 {
fn inc(&mut self) { *self += 1 }
}
fn foo() {
let mut n = 1;
fun_name(n);
}
fn $0fun_name(mut n: i32) {
n.inc();
}",
);
}
#[test]
fn shared_method_call() {
check_assist(
extract_function,
r"
trait I {
fn succ(&self);
}
impl I for i32 {
fn succ(&self) { *self + 1 }
}
fn foo() {
let mut n = 1;
$0n.succ();$0
}",
r"
trait I {
fn succ(&self);
}
impl I for i32 {
fn succ(&self) { *self + 1 }
}
fn foo() {
let mut n = 1;
fun_name(n);
}
fn $0fun_name(n: i32) {
n.succ();
}",
);
}
#[test]
fn mut_method_call_with_other_receiver() {
check_assist(
extract_function,
r"
trait I {
fn inc(&mut self, n: i32);
}
impl I for i32 {
fn inc(&mut self, n: i32) { *self += n }
}
fn foo() {
let mut n = 1;
$0let mut m = 2;
m.inc(n);$0
}",
r"
trait I {
fn inc(&mut self, n: i32);
}
impl I for i32 {
fn inc(&mut self, n: i32) { *self += n }
}
fn foo() {
let mut n = 1;
fun_name(n);
}
fn $0fun_name(n: i32) {
let mut m = 2;
m.inc(n);
}",
);
}
#[test]
fn non_copy_without_usages_after() {
check_assist(
extract_function,
r"
struct Counter(i32);
fn foo() {
let c = Counter(0);
$0let n = c.0;$0
}",
r"
struct Counter(i32);
fn foo() {
let c = Counter(0);
fun_name(c);
}
fn $0fun_name(c: Counter) {
let n = c.0;
}",
);
}
#[test]
fn non_copy_used_after() {
check_assist(
extract_function,
r"
struct Counter(i32);
fn foo() {
let c = Counter(0);
$0let n = c.0;$0
let m = c.0;
}",
r"
struct Counter(i32);
fn foo() {
let c = Counter(0);
fun_name(&c);
let m = c.0;
}
fn $0fun_name(c: &Counter) {
let n = c.0;
}",
);
}
#[test]
fn copy_used_after() {
check_assist(
extract_function,
r##"
#[lang = "copy"]
pub trait Copy {}
impl Copy for i32 {}
fn foo() {
let n = 0;
$0let m = n;$0
let k = n;
}"##,
r##"
#[lang = "copy"]
pub trait Copy {}
impl Copy for i32 {}
fn foo() {
let n = 0;
fun_name(n);
let k = n;
}
fn $0fun_name(n: i32) {
let m = n;
}"##,
)
}
#[test]
fn copy_custom_used_after() {
check_assist(
extract_function,
r##"
#[lang = "copy"]
pub trait Copy {}
struct Counter(i32);
impl Copy for Counter {}
fn foo() {
let c = Counter(0);
$0let n = c.0;$0
let m = c.0;
}"##,
r##"
#[lang = "copy"]
pub trait Copy {}
struct Counter(i32);
impl Copy for Counter {}
fn foo() {
let c = Counter(0);
fun_name(c);
let m = c.0;
}
fn $0fun_name(c: Counter) {
let n = c.0;
}"##,
);
}
#[test]
fn indented_stmts() {
check_assist(
extract_function,
r"
fn foo() {
if true {
loop {
$0let n = 1;
let m = 2;$0
}
}
}",
r"
fn foo() {
if true {
loop {
fun_name();
}
}
}
fn $0fun_name() {
let n = 1;
let m = 2;
}",
);
}
#[test]
fn indented_stmts_inside_mod() {
check_assist(
extract_function,
r"
mod bar {
fn foo() {
if true {
loop {
$0let n = 1;
let m = 2;$0
}
}
}
}",
r"
mod bar {
fn foo() {
if true {
loop {
fun_name();
}
}
}
fn $0fun_name() {
let n = 1;
let m = 2;
}
}",
);
}
#[test]
fn break_loop() {
check_assist(
extract_function,
r##"
enum Option<T> {
#[lang = "None"] None,
#[lang = "Some"] Some(T),
}
use Option::*;
fn foo() {
loop {
let n = 1;
$0let m = n + 1;
break;
let k = 2;$0
let h = 1 + k;
}
}"##,
r##"
enum Option<T> {
#[lang = "None"] None,
#[lang = "Some"] Some(T),
}
use Option::*;
fn foo() {
loop {
let n = 1;
let k = match fun_name(n) {
Some(value) => value,
None => break,
};
let h = 1 + k;
}
}
fn $0fun_name(n: i32) -> Option<i32> {
let m = n + 1;
return None;
let k = 2;
Some(k)
}"##,
);
}
#[test]
fn return_to_parent() {
check_assist(
extract_function,
r##"
#[lang = "copy"]
pub trait Copy {}
impl Copy for i32 {}
enum Result<T, E> {
#[lang = "Ok"] Ok(T),
#[lang = "Err"] Err(E),
}
use Result::*;
fn foo() -> i64 {
let n = 1;
$0let m = n + 1;
return 1;
let k = 2;$0
(n + k) as i64
}"##,
r##"
#[lang = "copy"]
pub trait Copy {}
impl Copy for i32 {}
enum Result<T, E> {
#[lang = "Ok"] Ok(T),
#[lang = "Err"] Err(E),
}
use Result::*;
fn foo() -> i64 {
let n = 1;
let k = match fun_name(n) {
Ok(value) => value,
Err(value) => return value,
};
(n + k) as i64
}
fn $0fun_name(n: i32) -> Result<i32, i64> {
let m = n + 1;
return Err(1);
let k = 2;
Ok(k)
}"##,
);
}
#[test]
fn break_and_continue() {
mark::check!(external_control_flow_break_and_continue);
check_assist_not_applicable(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0let m = n + 1;
break;
let k = 2;
continue;
let k = k + 1;$0
let r = n + k;
}
}"##,
);
}
#[test]
fn return_and_break() {
mark::check!(external_control_flow_return_and_bc);
check_assist_not_applicable(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0let m = n + 1;
break;
let k = 2;
return;
let k = k + 1;$0
let r = n + k;
}
}"##,
);
}
#[test]
fn break_loop_with_if() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let mut n = 1;
$0let m = n + 1;
break;
n += m;$0
let h = 1 + n;
}
}"##,
r##"
fn foo() {
loop {
let mut n = 1;
if fun_name(&mut n) {
break;
}
let h = 1 + n;
}
}
fn $0fun_name(n: &mut i32) -> bool {
let m = *n + 1;
return true;
*n += m;
false
}"##,
);
}
#[test]
fn break_loop_nested() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let mut n = 1;
$0let m = n + 1;
if m == 42 {
break;
}$0
let h = 1;
}
}"##,
r##"
fn foo() {
loop {
let mut n = 1;
if fun_name(n) {
break;
}
let h = 1;
}
}
fn $0fun_name(n: i32) -> bool {
let m = n + 1;
if m == 42 {
return true;
}
false
}"##,
);
}
#[test]
fn return_from_nested_loop() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0
let k = 1;
loop {
return;
}
let m = k + 1;$0
let h = 1 + m;
}
}"##,
r##"
fn foo() {
loop {
let n = 1;
let m = match fun_name() {
Some(value) => value,
None => return,
};
let h = 1 + m;
}
}
fn $0fun_name() -> Option<i32> {
let k = 1;
loop {
return None;
}
let m = k + 1;
Some(m)
}"##,
);
}
#[test]
fn break_from_nested_loop() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0let k = 1;
loop {
break;
}
let m = k + 1;$0
let h = 1 + m;
}
}"##,
r##"
fn foo() {
loop {
let n = 1;
let m = fun_name();
let h = 1 + m;
}
}
fn $0fun_name() -> i32 {
let k = 1;
loop {
break;
}
let m = k + 1;
m
}"##,
);
}
#[test]
fn break_from_nested_and_outer_loops() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0let k = 1;
loop {
break;
}
if k == 42 {
break;
}
let m = k + 1;$0
let h = 1 + m;
}
}"##,
r##"
fn foo() {
loop {
let n = 1;
let m = match fun_name() {
Some(value) => value,
None => break,
};
let h = 1 + m;
}
}
fn $0fun_name() -> Option<i32> {
let k = 1;
loop {
break;
}
if k == 42 {
return None;
}
let m = k + 1;
Some(m)
}"##,
);
}
#[test]
fn return_from_nested_fn() {
check_assist(
extract_function,
r##"
fn foo() {
loop {
let n = 1;
$0let k = 1;
fn test() {
return;
}
let m = k + 1;$0
let h = 1 + m;
}
}"##,
r##"
fn foo() {
loop {
let n = 1;
let m = fun_name();
let h = 1 + m;
}
}
fn $0fun_name() -> i32 {
let k = 1;
fn test() {
return;
}
let m = k + 1;
m
}"##,
);
}
#[test]
fn break_with_value() {
check_assist(
extract_function,
r##"
fn foo() -> i32 {
loop {
let n = 1;
$0let k = 1;
if k == 42 {
break 3;
}
let m = k + 1;$0
let h = 1;
}
}"##,
r##"
fn foo() -> i32 {
loop {
let n = 1;
if let Some(value) = fun_name() {
break value;
}
let h = 1;
}
}
fn $0fun_name() -> Option<i32> {
let k = 1;
if k == 42 {
return Some(3);
}
let m = k + 1;
None
}"##,
);
}
#[test]
fn break_with_value_and_return() {
check_assist(
extract_function,
r##"
fn foo() -> i64 {
loop {
let n = 1;
$0
let k = 1;
if k == 42 {
break 3;
}
let m = k + 1;$0
let h = 1 + m;
}
}"##,
r##"
fn foo() -> i64 {
loop {
let n = 1;
let m = match fun_name() {
Ok(value) => value,
Err(value) => break value,
};
let h = 1 + m;
}
}
fn $0fun_name() -> Result<i32, i64> {
let k = 1;
if k == 42 {
return Err(3);
}
let m = k + 1;
Ok(m)
}"##,
);
}
}