Auto merge of #223 - fitzgen:useful-helpers, r=emilio

Useful little helpers for Item and Type

Just a couple things I have found helpful when debugging, and should probably exist either way.

r? @emilio

Author: bors-servo

src/ir/item.rs

@@ -331,6 +331,12 @@ impl Item {
         self.kind().expect_type()
     }
 
+    /// Get a reference to this item's underlying `Type`, or `None` if this is
+    /// some other kind of item.
+    pub fn as_type(&self) -> Option<&Type> {
+        self.kind().as_type()
+    }
+
     /// Get a reference to this item's underlying `Function`. Panic if this is
     /// some other kind of item.
     pub fn expect_function(&self) -> &Function {
@@ -531,6 +537,11 @@ impl Item {
         ctx.opaque_by_name(&self.real_canonical_name(ctx, false, true))
     }
 
+    /// Is this a reference to another type?
+    pub fn is_type_ref(&self) -> bool {
+        self.as_type().map_or(false, |ty| ty.is_type_ref())
+    }
+
     /// Get the canonical name without taking into account the replaces
     /// annotation.
     ///

src/ir/ty.rs

@@ -136,6 +136,15 @@ impl Type {
         self.is_const
     }
 
+    /// Is this a reference to another type?
+    pub fn is_type_ref(&self) -> bool {
+        match self.kind {
+            TypeKind::ResolvedTypeRef(_) |
+            TypeKind::UnresolvedTypeRef(_, _, _) => true,
+            _ => false,
+        }
+    }
+
     /// What is the layout of this type?
     pub fn layout(&self, ctx: &BindgenContext) -> Option<Layout> {
         use std::mem;