Merge #1069

1069: Handle macro invocations in type contexts r=CohenArthur a=CohenArthur

Closes #1067 

This highlighted two issues where parsing types is not entirely correct, which I'll raise. The code necessary to handle macro invocations in these two places should already be implemented. 

Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>

Author: bors[bot]

gcc/rust/ast/rust-ast.h

@@ -1515,6 +1515,7 @@ class SingleASTNode
     TRAIT,
     IMPL,
     TRAIT_IMPL,
+    TYPE,
   };
 
 private:
@@ -1528,6 +1529,7 @@ class SingleASTNode
   std::unique_ptr<TraitItem> trait_item;
   std::unique_ptr<InherentImplItem> impl_item;
   std::unique_ptr<TraitImplItem> trait_impl_item;
+  std::unique_ptr<Type> type;
 
 public:
   SingleASTNode (std::unique_ptr<Expr> expr)
@@ -1558,6 +1560,10 @@ class SingleASTNode
     : kind (TRAIT_IMPL), trait_impl_item (std::move (trait_impl_item))
   {}
 
+  SingleASTNode (std::unique_ptr<Type> type)
+    : kind (TYPE), type (std::move (type))
+  {}
+
   SingleASTNode (SingleASTNode const &other)
   {
     kind = other.kind;
@@ -1590,6 +1596,10 @@ class SingleASTNode
       case TRAIT_IMPL:
 	trait_impl_item = other.trait_impl_item->clone_trait_impl_item ();
 	break;
+
+      case TYPE:
+	type = other.type->clone_type ();
+	break;
       }
   }
 
@@ -1625,6 +1635,10 @@ class SingleASTNode
       case TRAIT_IMPL:
 	trait_impl_item = other.trait_impl_item->clone_trait_impl_item ();
 	break;
+
+      case TYPE:
+	type = other.type->clone_type ();
+	break;
       }
     return *this;
   }
@@ -1699,6 +1713,12 @@ class SingleASTNode
     return std::move (trait_impl_item);
   }
 
+  std::unique_ptr<Type> take_type ()
+  {
+    rust_assert (!is_error ());
+    return std::move (type);
+  }
+
   void accept_vis (ASTVisitor &vis)
   {
     switch (kind)
@@ -1730,6 +1750,10 @@ class SingleASTNode
       case TRAIT_IMPL:
 	trait_impl_item->accept_vis (vis);
 	break;
+
+      case TYPE:
+	type->accept_vis (vis);
+	break;
       }
   }
 
@@ -1751,6 +1775,8 @@ class SingleASTNode
 	return impl_item == nullptr;
       case TRAIT_IMPL:
 	return trait_impl_item == nullptr;
+      case TYPE:
+	return type == nullptr;
       }
 
     gcc_unreachable ();
@@ -1774,7 +1800,9 @@ class SingleASTNode
       case IMPL:
 	return "Impl Item: " + impl_item->as_string ();
       case TRAIT_IMPL:
-	return "Trait Impl Item: " + impl_item->as_string ();
+	return "Trait Impl Item: " + trait_impl_item->as_string ();
+      case TYPE:
+	return "Type: " + type->as_string ();
       }
 
     gcc_unreachable ();
@@ -1799,6 +1827,18 @@ class ASTFragment
   std::vector<SingleASTNode> nodes;
   bool fragment_is_error;
 
+  /**
+   * We need to make a special case for Expression and Type fragments as only
+   * one Node will be extracted from the `nodes` vector
+   */
+
+  bool is_single_fragment () const { return nodes.size () == 1; }
+
+  bool is_single_fragment_kind (SingleASTNode::NodeType kind) const
+  {
+    return is_single_fragment () && nodes[0].get_kind () == kind;
+  }
+
 public:
   ASTFragment (std::vector<SingleASTNode> nodes, bool fragment_is_error = false)
     : nodes (std::move (nodes)), fragment_is_error (fragment_is_error)
@@ -1839,21 +1879,16 @@ class ASTFragment
 
   bool should_expand () const { return !is_error () && !nodes.empty (); }
 
-  /**
-   * We need to make a special case for Expression fragments as only one
-   * Node will be extracted from the `nodes` vector
-   */
-
-  bool is_expression_fragment () const
+  std::unique_ptr<Expr> take_expression_fragment ()
   {
-    return nodes.size () == 1
-	   && nodes[0].get_kind () == SingleASTNode::NodeType::EXPRESSION;
+    rust_assert (is_single_fragment_kind (SingleASTNode::NodeType::EXPRESSION));
+    return nodes[0].take_expr ();
   }
 
-  std::unique_ptr<Expr> take_expression_fragment ()
+  std::unique_ptr<Type> take_type_fragment ()
   {
-    rust_assert (is_expression_fragment ());
-    return nodes[0].take_expr ();
+    rust_assert (is_single_fragment_kind (SingleASTNode::NodeType::TYPE));
+    return nodes[0].take_type ();
   }
 
   void accept_vis (ASTVisitor &vis)