Allow attributes in generics of impl

src/items.rs

@@ -1512,12 +1512,16 @@ fn span_for_return(ret: &ast::FunctionRetTy) -> Span {
 
 fn span_for_ty_param(ty: &ast::TyParam) -> Span {
     // Note that ty.span is the span for ty.ident, not the whole item.
-    let lo = ty.span.lo;
+    let lo = if ty.attrs.is_empty() {
+        ty.span.lo
+    } else {
+        ty.attrs[0].span.lo
+    };
     if let Some(ref def) = ty.default {
         return mk_sp(lo, def.span.hi);
     }
     if ty.bounds.is_empty() {
-        return ty.span;
+        return mk_sp(lo, ty.span.hi);
     }
     let hi = match ty.bounds[ty.bounds.len() - 1] {
         ast::TyParamBound::TraitTyParamBound(ref ptr, _) => ptr.span.hi,

src/types.rs

@@ -509,6 +509,12 @@ impl Rewrite for ast::TyParamBounds {
 impl Rewrite for ast::TyParam {
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
         let mut result = String::with_capacity(128);
+        // FIXME: If there are more than one attributes, this will force multiline.
+        let attr_str = match (&*self.attrs).rewrite(context, shape) {
+            Some(ref rw) if !rw.is_empty() => format!("{} ", rw),
+            _ => String::new(),
+        };
+        result.push_str(&attr_str);
         result.push_str(&self.ident.to_string());
         if !self.bounds.is_empty() {
             if context.config.space_before_bound() {

tests/source/impls.rs

@@ -117,3 +117,8 @@ impl<ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNodeFoo> Issue1249<ConcreteTh
     // Creates a new flow constructor.
    fn foo() {}
 }
+
+// #1600
+impl<#[may_dangle] K, #[may_dangle] V> Drop for RawTable<K, V> {
+    fn drop() {}
+}

tests/target/impls.rs

@@ -149,3 +149,8 @@ impl<ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNodeFoo>
     // Creates a new flow constructor.
     fn foo() {}
 }
+
+// #1600
+impl<#[may_dangle] K, #[may_dangle] V> Drop for RawTable<K, V> {
+    fn drop() {}
+}