1 files changed, 252 insertions, 1 deletions
diff --git a/src/tools/rustfmt/tests/target/let_else.rs b/src/tools/rustfmt/tests/target/let_else.rs
index a6e816fb5..6554a0961 100644
--- a/src/tools/rustfmt/tests/target/let_else.rs
+++ b/src/tools/rustfmt/tests/target/let_else.rs
@@ -1,3 +1,254 @@
+// rustfmt-single_line_let_else_max_width: 100
+
 fn main() {
-    let Some(1) = Some(1) else { return };
+    // Although this won't compile it still parses so make sure we can format empty else blocks
+    let Some(x) = opt else {};
+
+    // let-else may be formatted on a single line if they are "short"
+    // and only contain a single expression
+    let Some(x) = opt else { return };
+
+    let Some(x) = opt else { return };
+
+    let Some(x) = opt else {
+        return;
+    };
+
+    let Some(x) = opt else {
+        // nope
+        return;
+    };
+
+    let Some(x) = opt else {
+        let y = 1;
+        return y;
+    };
+
+    let Some(x) = y.foo(
+        "abc",
+        fairly_long_identifier,
+        "def",
+        "123456",
+        "string",
+        "cheese",
+    ) else {
+        bar()
+    };
+
+    let Some(x) = abcdef()
+        .foo(
+            "abc",
+            some_really_really_really_long_ident,
+            "ident",
+            "123456",
+        )
+        .bar()
+        .baz()
+        .qux("fffffffffffffffff")
+    else {
+        foo_bar()
+    };
+}
+
+fn with_comments_around_else_keyword() {
+    let Some(x) = opt
+    /* pre else keyword block-comment */
+    else {
+        return;
+    };
+
+    let Some(x) = opt else
+    /* post else keyword block-comment */
+    {
+        return;
+    };
+
+    let Some(x) = opt
+    /* pre else keyword block-comment */
+    else
+    /* post else keyword block-comment */
+    {
+        return;
+    };
+
+    let Some(x) = opt
+    // pre else keyword line-comment
+    else {
+        return;
+    };
+
+    let Some(x) = opt else
+    // post else keyword line-comment
+    {
+        return;
+    };
+
+    let Some(x) = opt
+    // pre else keyword line-comment
+    else
+    // post else keyword line-comment
+    {
+        return;
+    };
+}
+
+fn unbreakable_initializer_expr_pre_formatting_let_else_length_near_max_width() {
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else block;` is 100 (max_width)
+    // Post Formatting:
+    // The formatting is left unchanged!
+    let Some(x) = some_really_really_really_really_really_really_really_long_name_A else { return };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else block;` is 100 (max_width)
+    // Post Formatting:
+    // The else keyword and opening brace remain on the same line as the initializer expr,
+    // and the else block is formatted over multiple lines because we can't fit the
+    // else block on the same line as the initializer expr.
+    let Some(x) = some_really_really_really_really_really_really_really_long_name___B else {
+        return;
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else block;` is 100 (max_width)
+    // Post Formatting:
+    // The else keyword and opening brace remain on the same line as the initializer expr,
+    // and the else block is formatted over multiple lines because we can't fit the
+    // else block on the same line as the initializer expr.
+    let Some(x) = some_really_really_really_really_long_name_____C else {
+        some_divergent_function()
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else block;` is 101 (> max_width)
+    // Post Formatting:
+    // The else keyword and opening brace remain on the same line as the initializer expr,
+    // and the else block is formatted over multiple lines because we can't fit the
+    // else block on the same line as the initializer expr.
+    let Some(x) = some_really_really_really_really_really_really_really_long_name__D else {
+        return;
+    };
+}
+
+fn unbreakable_initializer_expr_pre_formatting_length_up_to_opening_brace_near_max_width() {
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else {` is 99 (< max_width)
+    // Post Formatting:
+    // The else keyword and opening brace remain on the same line as the initializer expr,
+    // and the else block is formatted over multiple lines because we can't fit the
+    // else block on the same line as the initializer expr.
+    let Some(x) = some_really_really_really_really_really_really_really_really_long_name___E else {
+        return;
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init else {` is 101 (> max_width)
+    // Post Formatting:
+    // The else keyword and opening brace cannot fit on the same line as the initializer expr.
+    // They are formatted on the next line.
+    let Some(x) = some_really_really_really_really_really_really_really_really_long_name_____F
+    else {
+        return;
+    };
+}
+
+fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_near_max_width() {
+    // Pre Formatting:
+    // The length of `(indent)let pat = init` is 99 (< max_width)
+    // Post Formatting:
+    // The else keyword and opening brace cannot fit on the same line as the initializer expr.
+    // They are formatted on the next line.
+    let Some(x) = some_really_really_really_really_really_really_really_really_really_long_name___G
+    else {
+        return;
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init` is 100 (max_width)
+    // Post Formatting:
+    // Break after the `=` and put the initializer expr on it's own line.
+    // Because the initializer expr is multi-lined the else is placed on it's own line.
+    let Some(x) =
+        some_really_really_really_really_really_really_really_really_really_long_name____H
+    else {
+        return;
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init` is 109 (> max_width)
+    // Post Formatting:
+    // Break after the `=` and put the initializer expr on it's own line.
+    // Because the initializer expr is multi-lined the else is placed on it's own line.
+    // The initializer expr has a length of 91, which when indented on the next line
+    // The `(indent)init` line has a lengh of 99. This is the max length that the `init` can be
+    // before we start running into max_width issues. I suspect this is becuase the shape is
+    // accounting for the `;` at the end of the `let-else` statement.
+    let Some(x) =
+        some_really_really_really_really_really_really_really_really_really_really_long_name______I
+    else {
+        return;
+    };
+
+    // Pre Formatting:
+    // The length of `(indent)let pat = init` is 110 (> max_width)
+    // Post Formatting:
+    // Max length issues prevent us from formatting.
+    // The initializer expr has a length of 92, which if it would be indented on the next line
+    // the `(indent)init` line has a lengh of 100 which == max_width of 100.
+    // One might expect formatting to succeed, but I suspect the reason we hit max_width issues is
+    // because the Shape is accounting for the `;` at the end of the `let-else` statement.
+    let Some(x) = some_really_really_really_really_really_really_really_really_really_really_really_long_nameJ else {return};
+}
+
+fn long_patterns() {
+    let Foo {
+        x: Bar(..),
+        y: FooBar(..),
+        z: Baz(..),
+    } = opt
+    else {
+        return;
+    };
+
+    // with version=One we don't wrap long array patterns
+    let [aaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, cccccccccccccccccc, dddddddddddddddddd] = opt else {
+        return;
+    };
+
+    let ("aaaaaaaaaaaaaaaaaaa"
+    | "bbbbbbbbbbbbbbbbb"
+    | "cccccccccccccccccccccccc"
+    | "dddddddddddddddd"
+    | "eeeeeeeeeeeeeeee") = opt
+    else {
+        return;
+    };
+
+    let Some(Ok((Message::ChangeColor(super::color::Color::Rgb(r, g, b)), Point { x, y, z }))) =
+        opt
+    else {
+        return;
+    };
+}
+
+fn with_trailing_try_operator() {
+    // Currently the trailing ? forces the else on the next line
+    // This may be revisited in style edition 2024
+    let Some(next_bucket) = ranking_rules[cur_ranking_rule_index].next_bucket(
+        ctx,
+        logger,
+        &ranking_rule_universes[cur_ranking_rule_index],
+    )?
+    else {
+        return;
+    };
+
+    // Maybe this is a workaround?
+    let Ok(Some(next_bucket)) = ranking_rules[cur_ranking_rule_index].next_bucket(
+        ctx,
+        logger,
+        &ranking_rule_universes[cur_ranking_rule_index],
+    ) else {
+        return;
+    };
 }