Remove fallback for containing scopes

This wasn't necessary for msvc and caused issues where different types
with the same name such as different instantiations of `Option<T>` would
have colliding debuginfo. This confused the debugger which would pick
one of the type definitions and use for all types with that name even
though they had different layout.

Author: wesleywiser

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -1457,7 +1457,6 @@ struct EnumMemberDescriptionFactory<'ll, 'tcx> {
     enum_type: Ty<'tcx>,
     layout: TyAndLayout<'tcx>,
     tag_type_metadata: Option<&'ll DIType>,
-    containing_scope: &'ll DIScope,
     common_members: Vec<Option<&'ll DIType>>,
     span: Span,
 }
@@ -1488,11 +1487,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
 
         // This will always find the metadata in the type map.
         let fallback = use_enum_fallback(cx);
-        let self_metadata = if fallback {
-            self.containing_scope
-        } else {
-            type_metadata(cx, self.enum_type, self.span)
-        };
+        let self_metadata = type_metadata(cx, self.enum_type, self.span);
 
         match self.layout.variants {
             Variants::Single { index } => {
@@ -1607,7 +1602,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                         variant,
                         variant_info_for(dataful_variant),
                         Some(NicheTag),
-                        self.containing_scope,
+                        self_metadata,
                         self.span,
                     );
 
@@ -2085,7 +2080,6 @@ fn prepare_enum_metadata(
                 enum_type,
                 layout,
                 tag_type_metadata: discriminant_type_metadata,
-                containing_scope,
                 common_members: vec![],
                 span,
             }),
@@ -2238,7 +2232,6 @@ fn prepare_enum_metadata(
             enum_type,
             layout,
             tag_type_metadata: None,
-            containing_scope,
             common_members: outer_fields,
             span,
         }),