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https://github.com/rust-lang/rust-analyzer
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replace_match_with_if_let
works on more binary matches
This commit is contained in:
parent
f1819525f5
commit
251f0c6090
2 changed files with 141 additions and 24 deletions
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@ -176,21 +176,21 @@ fn make_else_arm(
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// ```
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pub(crate) fn replace_match_with_if_let(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
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let match_expr: ast::MatchExpr = ctx.find_node_at_offset()?;
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let mut arms = match_expr.match_arm_list()?.arms();
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let first_arm = arms.next()?;
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let second_arm = arms.next()?;
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let (first_arm, second_arm) = (arms.next()?, arms.next()?);
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if arms.next().is_some() || first_arm.guard().is_some() || second_arm.guard().is_some() {
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return None;
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}
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let condition_expr = match_expr.expr()?;
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let (if_let_pat, then_expr, else_expr) = if is_pat_wildcard_or_sad(&ctx.sema, &first_arm.pat()?)
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{
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(second_arm.pat()?, second_arm.expr()?, first_arm.expr()?)
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} else if is_pat_wildcard_or_sad(&ctx.sema, &second_arm.pat()?) {
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(first_arm.pat()?, first_arm.expr()?, second_arm.expr()?)
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} else {
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return None;
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};
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let (if_let_pat, then_expr, else_expr) = pick_pattern_and_expr_order(
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&ctx.sema,
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first_arm.pat()?,
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second_arm.pat()?,
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first_arm.expr()?,
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second_arm.expr()?,
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)?;
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let scrutinee = match_expr.expr()?;
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let target = match_expr.syntax().text_range();
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acc.add(
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@ -198,26 +198,25 @@ pub(crate) fn replace_match_with_if_let(acc: &mut Assists, ctx: &AssistContext)
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"Replace with if let",
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target,
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move |edit| {
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let condition = make::condition(condition_expr, Some(if_let_pat));
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let condition = make::condition(scrutinee, Some(if_let_pat));
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let then_block = match then_expr.reset_indent() {
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ast::Expr::BlockExpr(block) => block,
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expr => make::block_expr(iter::empty(), Some(expr)),
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};
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let else_expr = match else_expr {
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ast::Expr::BlockExpr(block)
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if block.statements().count() == 0 && block.tail_expr().is_none() =>
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{
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None
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}
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ast::Expr::TupleExpr(tuple) if tuple.fields().count() == 0 => None,
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ast::Expr::BlockExpr(block) if block.is_empty() => None,
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ast::Expr::TupleExpr(tuple) if tuple.fields().next().is_none() => None,
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expr => Some(expr),
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};
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let if_let_expr = make::expr_if(
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condition,
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then_block,
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else_expr.map(|else_expr| {
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ast::ElseBranch::Block(make::block_expr(iter::empty(), Some(else_expr)))
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}),
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else_expr
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.map(|expr| match expr {
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ast::Expr::BlockExpr(block) => block,
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expr => (make::block_expr(iter::empty(), Some(expr))),
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})
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.map(ast::ElseBranch::Block),
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)
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.indent(IndentLevel::from_node(match_expr.syntax()));
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@ -226,11 +225,50 @@ pub(crate) fn replace_match_with_if_let(acc: &mut Assists, ctx: &AssistContext)
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)
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}
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fn is_pat_wildcard_or_sad(sema: &hir::Semantics<RootDatabase>, pat: &ast::Pat) -> bool {
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/// Pick the pattern for the if let condition and return the expressions for the `then` body and `else` body in that order.
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fn pick_pattern_and_expr_order(
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sema: &hir::Semantics<RootDatabase>,
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pat: ast::Pat,
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pat2: ast::Pat,
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expr: ast::Expr,
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expr2: ast::Expr,
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) -> Option<(ast::Pat, ast::Expr, ast::Expr)> {
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let res = match (pat, pat2) {
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(ast::Pat::WildcardPat(_), _) => return None,
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(pat, sad_pat) if is_sad_pat(sema, &sad_pat) => (pat, expr, expr2),
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(sad_pat, pat) if is_sad_pat(sema, &sad_pat) => (pat, expr2, expr),
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(pat, pat2) => match (binds_name(&pat), binds_name(&pat2)) {
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(true, true) => return None,
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(true, false) => (pat, expr, expr2),
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(false, true) => (pat2, expr2, expr),
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(false, false) => (pat, expr, expr2),
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},
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};
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Some(res)
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}
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fn binds_name(pat: &ast::Pat) -> bool {
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let binds_name_v = |pat| binds_name(&pat);
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match pat {
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ast::Pat::IdentPat(_) => true,
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ast::Pat::MacroPat(_) => true,
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ast::Pat::OrPat(pat) => pat.pats().any(binds_name_v),
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ast::Pat::SlicePat(pat) => pat.pats().any(binds_name_v),
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ast::Pat::TuplePat(it) => it.fields().any(binds_name_v),
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ast::Pat::TupleStructPat(it) => it.fields().any(binds_name_v),
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ast::Pat::RecordPat(it) => it
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.record_pat_field_list()
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.map_or(false, |rpfl| rpfl.fields().flat_map(|rpf| rpf.pat()).any(binds_name_v)),
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ast::Pat::RefPat(pat) => pat.pat().map_or(false, binds_name_v),
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ast::Pat::BoxPat(pat) => pat.pat().map_or(false, binds_name_v),
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ast::Pat::ParenPat(pat) => pat.pat().map_or(false, binds_name_v),
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_ => false,
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}
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}
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fn is_sad_pat(sema: &hir::Semantics<RootDatabase>, pat: &ast::Pat) -> bool {
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sema.type_of_pat(pat)
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.and_then(|ty| TryEnum::from_ty(sema, &ty))
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.map(|it| it.sad_pattern().syntax().text() == pat.syntax().text())
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.unwrap_or_else(|| matches!(pat, ast::Pat::WildcardPat(_)))
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.map_or(false, |it| it.sad_pattern().syntax().text() == pat.syntax().text())
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}
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#[cfg(test)]
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@ -662,4 +700,79 @@ fn main() {
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"#,
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)
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}
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#[test]
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fn replace_match_with_if_let_exhaustive() {
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check_assist(
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replace_match_with_if_let,
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r#"
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fn print_source(def_source: ModuleSource) {
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match def_so$0urce {
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ModuleSource::SourceFile(..) => { println!("source file"); }
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ModuleSource::Module(..) => { println!("module"); }
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}
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}
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"#,
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r#"
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fn print_source(def_source: ModuleSource) {
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if let ModuleSource::SourceFile(..) = def_source { println!("source file"); } else { println!("module"); }
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}
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"#,
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)
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}
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#[test]
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fn replace_match_with_if_let_prefer_name_bind() {
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check_assist(
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replace_match_with_if_let,
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r#"
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fn foo() {
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match $0Foo(0) {
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Foo(_) => (),
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Bar(bar) => println!("bar {}", bar),
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}
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}
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"#,
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r#"
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fn foo() {
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if let Bar(bar) = Foo(0) {
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println!("bar {}", bar)
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}
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}
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"#,
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);
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check_assist(
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replace_match_with_if_let,
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r#"
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fn foo() {
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match $0Foo(0) {
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Bar(bar) => println!("bar {}", bar),
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Foo(_) => (),
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}
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}
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"#,
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r#"
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fn foo() {
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if let Bar(bar) = Foo(0) {
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println!("bar {}", bar)
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}
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}
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"#,
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);
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}
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#[test]
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fn replace_match_with_if_let_rejects_double_name_bindings() {
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check_assist_not_applicable(
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replace_match_with_if_let,
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r#"
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fn foo() {
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match $0Foo(0) {
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Foo(foo) => println!("bar {}", foo),
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Bar(bar) => println!("bar {}", bar),
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}
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}
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"#,
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);
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}
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}
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@ -49,6 +49,10 @@ impl ast::BlockExpr {
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pub fn items(&self) -> AstChildren<ast::Item> {
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support::children(self.syntax())
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}
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pub fn is_empty(&self) -> bool {
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self.statements().next().is_none() && self.tail_expr().is_none()
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}
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}
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impl ast::Expr {
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