resolve: Fix a false positive "cannot reexport" error for ambiguous glob sets

compiler/rustc_resolve/src/imports.rs

@@ -822,6 +822,10 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 for decl in [resolution.non_glob_decl, resolution.glob_decl] {
                     if let Some(decl) = decl
                         && let DeclKind::Import { source_decl, import } = decl.kind
+                        // FIXME: Do not check visibility-ambiguous imports for now. To check them
+                        // properly we need to preserve all imports in ambiguous glob sets and
+                        // check them all individually.
+                        && decl.ambiguity_vis_max.get().is_none()
                     {
                         // The source entity is too private to be reexported
                         // with the given import declaration's visibility.

tests/ui/imports/ambiguous-import-visibility-globglob-reexport.rs

@@ -0,0 +1,16 @@
+// Regression test for issue #156264
+
+//@ check-pass
+
+mod m_pub {
+    pub struct S {}
+}
+
+mod m_crate {
+    pub(crate) use crate::m_pub::S;
+}
+
+pub(crate) use m_crate::*;
+pub use m_pub::*;
+
+fn main() {}