Fix wrong indentation on type alias

src/expr.rs

@@ -2754,11 +2754,13 @@ pub fn rewrite_assign_rhs<S: Into<String>, R: Rewrite>(
     shape: Shape,
 ) -> Option<String> {
     let lhs = lhs.into();
-    let last_line_width = last_line_width(&lhs) - if lhs.contains('\n') {
-        shape.indent.width()
-    } else {
-        0
-    };
+    let last_line_width = last_line_width(&lhs)
+        .checked_sub(if lhs.contains('\n') {
+            shape.indent.width()
+        } else {
+            0
+        })
+        .unwrap_or(0);
     // 1 = space between operator and rhs.
     let orig_shape = shape.offset_left(last_line_width + 1).unwrap_or(Shape {
         width: 0,

src/items.rs

@@ -1365,9 +1365,11 @@ pub fn rewrite_type_alias(
     result.push_str(&ident.to_string());
 
     // 2 = `= `
-    let shape = Shape::indented(indent + result.len(), context.config).sub_width(2)?;
+    let g_shape = Shape::indented(indent, context.config)
+        .offset_left(result.len())?
+        .sub_width(2)?;
     let g_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo());
-    let generics_str = rewrite_generics(context, generics, shape, g_span)?;
+    let generics_str = rewrite_generics(context, generics, g_shape, g_span)?;
     result.push_str(&generics_str);
 
     let where_budget = context.budget(last_line_width(&result));
@@ -1386,32 +1388,14 @@ pub fn rewrite_type_alias(
     )?;
     result.push_str(&where_clause_str);
     if where_clause_str.is_empty() {
-        result.push_str(" = ");
+        result.push_str(" =");
     } else {
-        result.push_str(&format!("\n{}= ", indent.to_string(context.config)));
-    }
-
-    let line_width = last_line_width(&result);
-    // This checked_sub may fail as the extra space after '=' is not taken into account
-    // In that case the budget is set to 0 which will make ty.rewrite retry on a new line
-    let budget = context.budget(indent.width() + line_width + ";".len());
-    let type_indent = indent + line_width;
-    // Try to fit the type on the same line
-    let ty_str = ty.rewrite(context, Shape::legacy(budget, type_indent))
-        .or_else(|| {
-            // The line was too short, try to put the type on the next line
-
-            // Remove the space after '='
-            result.pop();
-            let type_indent = indent.block_indent(context.config);
-            result.push('\n');
-            result.push_str(&type_indent.to_string(context.config));
-            let budget = context.budget(type_indent.width() + ";".len());
-            ty.rewrite(context, Shape::legacy(budget, type_indent))
-        })?;
-    result.push_str(&ty_str);
-    result.push_str(";");
-    Some(result)
+        result.push_str(&format!("\n{}=", indent.to_string(context.config)));
+    }
+
+    // 1 = ";"
+    let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
+    rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
 }
 
 fn type_annotation_spacing(config: &Config) -> (&str, &str) {

tests/target/type_alias.rs

@@ -26,9 +26,8 @@ pub type LongGenericListTest<
 
 pub type Exactly100CharsTest<'a, 'b, 'c, 'd, LONGPARAMETERNAME, LONGPARAMETERNAME, A, B> = Vec<i32>;
 
-pub type Exactly101CharsTest<'a, 'b, 'c, 'd, LONGPARAMETERNAME, LONGPARAMETERNAME, A, B> = Vec<
-    Test,
->;
+pub type Exactly101CharsTest<'a, 'b, 'c, 'd, LONGPARAMETERNAME, LONGPARAMETERNAME, A, B> =
+    Vec<Test>;
 
 pub type Exactly100CharsToEqualTest<'a, 'b, 'c, 'd, LONGPARAMETERNAME, LONGPARAMETERNAME, A, B, C> =
     Vec<i32>;
@@ -71,11 +70,7 @@ where
 type RegisterPlugin = unsafe fn(pt: *const c_char, plugin: *mut c_void, data: *mut CallbackData);
 
 // #1683
-pub type Between<Lhs, Rhs> = super::operators::Between<
-    Lhs,
-    super::operators::And<AsExpr<Rhs, Lhs>, AsExpr<Rhs, Lhs>>,
->;
-pub type NotBetween<Lhs, Rhs> = super::operators::NotBetween<
-    Lhs,
-    super::operators::And<AsExpr<Rhs, Lhs>, AsExpr<Rhs, Lhs>>,
->;
+pub type Between<Lhs, Rhs> =
+    super::operators::Between<Lhs, super::operators::And<AsExpr<Rhs, Lhs>, AsExpr<Rhs, Lhs>>>;
+pub type NotBetween<Lhs, Rhs> =
+    super::operators::NotBetween<Lhs, super::operators::And<AsExpr<Rhs, Lhs>, AsExpr<Rhs, Lhs>>>;