codegen: Reuse the next_child_local_id hack for template instantiations.

This should be good enough, following the pattern of anonymous items, and should
prevent most of the current noise in stylo updates.

Closes #620
Fixes #619

1 files changed, 2 insertions, 2 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 06e3a4f6..2f8ad805 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -760,8 +760,8 @@ impl CodeGenerator for TemplateInstantiation {
 
             let name = item.canonical_name(ctx);
             let fn_name = format!("__bindgen_test_layout_{}_instantiation_{}",
-                                  name,
-                                  item.id().as_usize());
+                                  name, item.exposed_id(ctx));
+
             let fn_name = ctx.rust_ident_raw(&fn_name);
 
             let prefix = ctx.trait_prefix();