Merge pull request rust-lang#3035 from topecongiro/issue-3006

Format generics on associated types

Author: nrc

src/items.rs

@@ -1715,11 +1715,16 @@ fn rewrite_static(
 pub fn rewrite_associated_type(
     ident: ast::Ident,
     ty_opt: Option<&ptr::P<ast::Ty>>,
+    generics: &ast::Generics,
     generic_bounds_opt: Option<&ast::GenericBounds>,
     context: &RewriteContext,
     indent: Indent,
 ) -> Option<String> {
-    let prefix = format!("type {}", rewrite_ident(context, ident));
+    let ident_str = rewrite_ident(context, ident);
+    // 5 = "type "
+    let generics_shape = Shape::indented(indent, context.config).offset_left(5)?;
+    let generics_str = rewrite_generics(context, ident_str, generics, generics_shape)?;
+    let prefix = format!("type {}", generics_str);
 
     let type_bounds_str = if let Some(bounds) = generic_bounds_opt {
         if bounds.is_empty() {
@@ -1746,21 +1751,23 @@ pub fn rewrite_associated_type(
 pub fn rewrite_existential_impl_type(
     context: &RewriteContext,
     ident: ast::Ident,
+    generics: &ast::Generics,
     generic_bounds: &ast::GenericBounds,
     indent: Indent,
 ) -> Option<String> {
-    rewrite_associated_type(ident, None, Some(generic_bounds), context, indent)
+    rewrite_associated_type(ident, None, generics, Some(generic_bounds), context, indent)
         .map(|s| format!("existential {}", s))
 }
 
 pub fn rewrite_associated_impl_type(
     ident: ast::Ident,
     defaultness: ast::Defaultness,
     ty_opt: Option<&ptr::P<ast::Ty>>,
+    generics: &ast::Generics,
     context: &RewriteContext,
     indent: Indent,
 ) -> Option<String> {
-    let result = rewrite_associated_type(ident, ty_opt, None, context, indent)?;
+    let result = rewrite_associated_type(ident, ty_opt, generics, None, context, indent)?;
 
     match defaultness {
         ast::Defaultness::Default => Some(format!("default {}", result)),

src/visitor.rs

@@ -497,6 +497,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                 let rewrite = rewrite_associated_type(
                     ti.ident,
                     type_default.as_ref(),
+                    &ti.generics,
                     Some(generic_bounds),
                     &self.get_context(),
                     self.block_indent,
@@ -535,6 +536,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                     ii.ident,
                     ii.defaultness,
                     Some(ty),
+                    &ii.generics,
                     &self.get_context(),
                     self.block_indent,
                 );
@@ -544,6 +546,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                 let rewrite = rewrite_existential_impl_type(
                     &self.get_context(),
                     ii.ident,
+                    &ii.generics,
                     generic_bounds,
                     self.block_indent,
                 );

tests/source/trait.rs

@@ -97,3 +97,12 @@ trait FooBar = Foo
 auto trait Example {}
 pub auto trait PubExample {}
 pub unsafe auto trait PubUnsafeExample {}
+
+// #3006
+trait Foo<'a> {
+    type Bar<  'a  >;
+}
+
+impl<'a> Foo<'a> for i32 {
+    type Bar<  'a  > = i32;
+}

tests/target/trait.rs

@@ -135,3 +135,12 @@ trait FooBar = Foo
 auto trait Example {}
 pub auto trait PubExample {}
 pub unsafe auto trait PubUnsafeExample {}
+
+// #3006
+trait Foo<'a> {
+    type Bar<'a>;
+}
+
+impl<'a> Foo<'a> for i32 {
+    type Bar<'a> = i32;
+}