Support variantful generators

This allows generators to overlap fields using variants.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 31348b99c5a..bbcd3c220d6 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -691,9 +691,12 @@ pub fn type_metadata(
                                    usage_site_span).finalize(cx)
         }
         ty::Generator(def_id, substs,  _) => {
-            let upvar_tys : Vec<_> = substs.field_tys(def_id, cx.tcx).map(|t| {
+            // TODO handle variant fields
+            let upvar_tys : Vec<_> = substs.prefix_tys(def_id, cx.tcx).map(|t| {
                 cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), t)
             }).collect();
+            // TODO use prepare_enum_metadata and update it to handle multiple
+            // fields in the outer layout.
             prepare_tuple_metadata(cx,
                                    t,
                                    &upvar_tys,
@@ -1818,6 +1821,7 @@ fn prepare_enum_metadata(
     };
 
     // The variant part must be wrapped in a struct according to DWARF.
+    // TODO create remaining fields here, if any.
     let type_array = create_DIArray(DIB(cx), &[Some(variant_part)]);
     let struct_wrapper = unsafe {
         llvm::LLVMRustDIBuilderCreateStructType(