diff --git a/src/items.rs b/src/items.rs
index b8fde7fbb0b..d06fc9b2b8c 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -446,58 +446,21 @@ impl<'a> FmtVisitor<'a> {
}
pub fn format_impl(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
- if let ast::ItemKind::Impl(unsafety,
- polarity,
- ref generics,
- ref trait_ref,
- ref self_ty,
- ref items) = item.node {
+ if let ast::ItemKind::Impl(_, _, ref generics, ref trait_ref, _, ref items) = item.node {
let mut result = String::new();
- result.push_str(&*format_visibility(&item.vis));
- result.push_str(format_unsafety(unsafety));
- result.push_str("impl");
+ // First try to format the ref and type without a split at the 'for'.
+ let mut ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset, false));
- let lo = context.codemap.span_after(item.span, "impl");
- let hi = match *trait_ref {
- Some(ref tr) => tr.path.span.lo,
- None => self_ty.span.lo,
- };
- let generics_str = try_opt!(rewrite_generics(context,
- generics,
- offset,
- context.config.max_width,
- offset + result.len(),
- mk_sp(lo, hi)));
- result.push_str(&generics_str);
-
- // FIXME might need to linebreak in the impl header, here would be a
- // good place.
- result.push(' ');
- if polarity == ast::ImplPolarity::Negative {
- result.push_str("!");
- }
- if let Some(ref trait_ref) = *trait_ref {
- let budget = try_opt!(context.config.max_width.checked_sub(result.len()));
- let indent = offset + result.len();
- result.push_str(&*try_opt!(trait_ref.rewrite(context, budget, indent)));
- result.push_str(" for ");
- }
-
- let mut used_space = result.len();
- if generics.where_clause.predicates.is_empty() {
- // If there is no where clause adapt budget for type formatting to take space and curly
- // brace into account.
- match context.config.item_brace_style {
- BraceStyle::AlwaysNextLine => {}
- BraceStyle::PreferSameLine => used_space += 2,
- BraceStyle::SameLineWhere => used_space += 2,
+ // If there is a line break present in the first result format it again
+ // with a split at the 'for'. Skip this if there is no trait ref and
+ // therefore no 'for'.
+ if let Some(_) = *trait_ref {
+ if ref_and_type.contains('\n') {
+ ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset, true));
}
}
-
- let budget = try_opt!(context.config.max_width.checked_sub(used_space));
- let indent = offset + result.len();
- result.push_str(&*try_opt!(self_ty.rewrite(context, budget, indent)));
+ result.push_str(&ref_and_type);
let where_budget = try_opt!(context.config.max_width.checked_sub(last_line_width(&result)));
let where_clause_str = try_opt!(rewrite_where_clause(context,
@@ -594,6 +557,76 @@ fn is_impl_single_line(context: &RewriteContext,
!contains_comment(&snippet[open_pos..]))
}
+fn format_impl_ref_and_type(context: &RewriteContext,
+ item: &ast::Item,
+ offset: Indent,
+ split_at_for: bool)
+ -> Option<String> {
+ if let ast::ItemKind::Impl(unsafety, polarity, ref generics, ref trait_ref, ref self_ty, _) =
+ item.node {
+ let mut result = String::new();
+
+ result.push_str(&*format_visibility(&item.vis));
+ result.push_str(format_unsafety(unsafety));
+ result.push_str("impl");
+
+ let lo = context.codemap.span_after(item.span, "impl");
+ let hi = match *trait_ref {
+ Some(ref tr) => tr.path.span.lo,
+ None => self_ty.span.lo,
+ };
+ let generics_str = try_opt!(rewrite_generics(context,
+ generics,
+ offset,
+ context.config.max_width,
+ offset + result.len(),
+ mk_sp(lo, hi)));
+ result.push_str(&generics_str);
+
+ result.push(' ');
+ if polarity == ast::ImplPolarity::Negative {
+ result.push('!');
+ }
+ if let Some(ref trait_ref) = *trait_ref {
+ let budget = try_opt!(context.config.max_width.checked_sub(result.len()));
+ let indent = offset + result.len();
+ result.push_str(&*try_opt!(trait_ref.rewrite(context, budget, indent)));
+
+ if split_at_for {
+ result.push('\n');
+
+ // Add indentation of one additional tab.
+ let width = context.block_indent.width() + context.config.tab_spaces;
+ let for_indent = Indent::new(0, width);
+ result.push_str(&for_indent.to_string(context.config));
+
+ result.push_str("for ");
+ } else {
+ result.push_str(" for ");
+ }
+ }
+
+ let mut used_space = last_line_width(&result);
+ if generics.where_clause.predicates.is_empty() {
+ // If there is no where clause adapt budget for type formatting to take space and curly
+ // brace into account.
+ match context.config.item_brace_style {
+ BraceStyle::AlwaysNextLine => {}
+ BraceStyle::PreferSameLine => used_space += 2,
+ BraceStyle::SameLineWhere => used_space += 2,
+ }
+ }
+
+ let budget = try_opt!(context.config.max_width.checked_sub(used_space));
+ let indent = offset + result.len();
+ result.push_str(&*try_opt!(self_ty.rewrite(context, budget, indent)));
+
+ Some(result)
+ } else {
+ unreachable!();
+ }
+}
+
pub fn format_struct(context: &RewriteContext,
item_name: &str,
ident: ast::Ident,
diff --git a/tests/source/impls.rs b/tests/source/impls.rs
index 5fbcecb9700..6d65b8b4a7a 100644
--- a/tests/source/impls.rs
+++ b/tests/source/impls.rs
@@ -100,3 +100,6 @@ mod m {
impl<BorrowType, K, V, NodeType, HandleType> Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
}
+
+impl<BorrowType, K, V, NodeType, HandleType> PartialEq for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
+}
diff --git a/tests/target/impls.rs b/tests/target/impls.rs
index 03045c21ac5..87791d25648 100644
--- a/tests/target/impls.rs
+++ b/tests/target/impls.rs
@@ -128,3 +128,7 @@ mod m {
impl<BorrowType, K, V, NodeType, HandleType> Handle<NodeRef<BorrowType, K, V, NodeType>,
HandleType> {
}
+
+impl<BorrowType, K, V, NodeType, HandleType> PartialEq
+ for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
+}