fix(resolve): replace bindings to dummy for unresolved imports

2 files changed, 7 insertions, 5 deletions

diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index 9e4429507b1..a2da9833c66 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -405,11 +405,12 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         t
     }
 
-    // Define a dummy resolution containing a `Res::Err` as a placeholder for a failed resolution,
-    // also mark such failed imports as used to avoid duplicate diagnostics.
-    fn import_dummy_binding(&mut self, import: &'a Import<'a>) {
+    // Define a dummy resolution containing a `Res::Err` as a placeholder for a failed
+    // or indeterminate resolution, also mark such failed imports as used to avoid duplicate diagnostics.
+    fn import_dummy_binding(&mut self, import: &'a Import<'a>, is_indeterminate: bool) {
         if let ImportKind::Single { target, ref target_bindings, .. } = import.kind {
-            if target_bindings.iter().any(|binding| binding.get().is_some()) {
+            if !(is_indeterminate || target_bindings.iter().all(|binding| binding.get().is_none()))
+            {
                 return; // Has resolution, do not create the dummy binding
             }
             let dummy_binding = self.dummy_binding;
@@ -474,7 +475,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
 
             // If this import is unresolved then create a dummy import
             // resolution for it so that later resolve stages won't complain.
-            self.import_dummy_binding(import);
+            self.import_dummy_binding(import, is_indeterminate);
 
             if let Some(err) = unresolved_import_error {
                 if let ImportKind::Single { source, ref source_bindings, .. } = import.kind {
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 323b78fcd98..4144a4b40d4 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -85,6 +85,7 @@ pub mod rustdoc;
 
 fluent_messages! { "../messages.ftl" }
 
+#[derive(Debug)]
 enum Weak {
     Yes,
     No,