wrap `else {` for long, single-lined initializer expressions

This helps to prevent max width errors.

3 files changed, 20 insertions, 16 deletions

diff --git a/src/items.rs b/src/items.rs
index c2b9a26708d..97a76f6bb32 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -175,8 +175,10 @@ fn same_line_else_kw_and_brace(
     init_shape: Shape,
 ) -> bool {
     if !init_str.contains('\n') {
-        // initializer expression is single lined so the "else {" should be placed on the same line
-        return true;
+        // initializer expression is single lined. The "else {" can only be placed on the same line
+        // as the initializer expression if there is enough room for it.
+        // 7 = ` else {`
+        return init_shape.width.saturating_sub(init_str.len()) >= 7;
     }
 
     // 1. The initializer expression ends with one or more `)`, `]`, `}`.
diff --git a/tests/source/let_else.rs b/tests/source/let_else.rs
index 78465e64edc..9c02117c6e8 100644
--- a/tests/source/let_else.rs
+++ b/tests/source/let_else.rs
@@ -79,18 +79,18 @@ fn unbreakable_initializer_expr_pre_formatting_let_else_length_near_max_width()
 
 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 100 (max_width)
+    // 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};
+    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 remain on the same line as the initializer expr,
-    // which leads to the `{` exceeding the max width
+    // 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};
 }
 
@@ -98,8 +98,8 @@ fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_n
     // Pre Formatting:
     // The length of `(indent)let pat = init` is 99 (< max_width)
     // Post Formatting:
-    // The else keyword and opening brace remain on the same line as the initializer expr,
-    // which leads to the `else {` exceeding the max width
+    // 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:
diff --git a/tests/target/let_else.rs b/tests/target/let_else.rs
index 5ada7d44657..88115d129aa 100644
--- a/tests/target/let_else.rs
+++ b/tests/target/let_else.rs
@@ -130,21 +130,22 @@ fn unbreakable_initializer_expr_pre_formatting_let_else_length_near_max_width()
 
 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 100 (max_width)
+    // 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 {
+    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 remain on the same line as the initializer expr,
-    // which leads to the `{` exceeding the max width
-    let Some(x) = some_really_really_really_really_really_really_really_really_long_name_____F else {
+    // 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;
     };
 }
@@ -153,9 +154,10 @@ fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_n
     // Pre Formatting:
     // The length of `(indent)let pat = init` is 99 (< max_width)
     // Post Formatting:
-    // The else keyword and opening brace remain on the same line as the initializer expr,
-    // which leads to the `else {` exceeding the max width
-    let Some(x) = some_really_really_really_really_really_really_really_really_really_long_name___G else {
+    // 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;
     };