Auto merge of #1239 - emilio:cyclic-typedef-better, r=fitzgen

codegen: Make the cyclic typedef name detection catch more cases.

By looking through typedefs, we also catch more complex cases like the ones that
appear on Android's stdlib.

Fixes #946

Author: bors-servo

src/codegen/mod.rs

@@ -614,14 +614,20 @@ impl CodeGenerator for Type {
                     .resolve(ctx);
                 let name = item.canonical_name(ctx);
 
-                // Try to catch the common pattern:
-                //
-                // typedef struct foo { ... } foo;
-                //
-                // here.
-                //
-                if inner_item.canonical_name(ctx) == name {
-                    return;
+                {
+                    let through_type_aliases = inner.into_resolver()
+                        .through_type_refs()
+                        .through_type_aliases()
+                        .resolve(ctx);
+
+                    // Try to catch the common pattern:
+                    //
+                    // typedef struct foo { ... } foo;
+                    //
+                    // here, and also other more complex cases like #946.
+                    if through_type_aliases.canonical_name(ctx) == name {
+                        return;
+                    }
                 }
 
                 // If this is a known named type, disallow generating anything

tests/expectations/tests/issue-946.rs

@@ -0,0 +1,21 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct foo {}
+#[test]
+fn bindgen_test_layout_foo() {
+    assert_eq!(
+        ::std::mem::size_of::<foo>(),
+        0usize,
+        concat!("Size of: ", stringify!(foo))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<foo>(),
+        1usize,
+        concat!("Alignment of ", stringify!(foo))
+    );
+}
+pub type bar = foo;

tests/headers/issue-946.h

@@ -0,0 +1,5 @@
+struct foo { };
+
+typedef struct foo bar;
+
+typedef bar foo;