compiler: work around OPV bug

This can be reverted once #23902 is fixed.

Author: mlugg

src/Compilation.zig

@@ -3549,9 +3549,12 @@ pub fn getAllErrorsAlloc(comp: *Compilation) !ErrorBundle {
             const end = start + tree.tokenSlice(failed.import_token).len;
             const loc = std.zig.findLineColumn(source.bytes, start);
             try bundle.addRootErrorMessage(.{
-                .msg = switch (failed.kind) {
-                    .file_outside_module_root => try bundle.addString("import of file outside module path"),
-                },
+                // There is currently only one field in `kind`, so uncommenting it exposes a compiler bug: #23902
+                //.msg = switch (failed.kind) {
+                //    .file_outside_module_root => try bundle.addString("import of file outside module path"),
+                //},
+                .msg = try bundle.addString("import of file outside module path"),
+
                 .src_loc = try bundle.addSourceLocation(.{
                     .src_path = try bundle.printString("{}", .{file.path.fmt(comp)}),
                     .span_start = start,

src/Zcu.zig

@@ -222,7 +222,8 @@ failed_imports: std.ArrayListUnmanaged(struct {
     file_index: File.Index,
     import_string: Zir.NullTerminatedString,
     import_token: Ast.TokenIndex,
-    kind: enum { file_outside_module_root },
+    // There is currently only one field in `kind`, so uncommenting it exposes a compiler bug: #23902
+    //kind: enum { file_outside_module_root },
 }) = .empty,
 failed_exports: std.AutoArrayHashMapUnmanaged(Export.Index, *ErrorMsg) = .empty,
 /// If analysis failed due to a cimport error, the corresponding Clang errors

src/Zcu/PerThread.zig

@@ -2233,7 +2233,8 @@ pub fn computeAliveFiles(pt: Zcu.PerThread) Allocator.Error!bool {
                         .file_index = file_idx,
                         .import_string = item.data.name,
                         .import_token = item.data.token,
-                        .kind = .file_outside_module_root,
+                        // There is currently only one field in `kind`, so uncommenting it exposes a compiler bug: #23902
+                        //.kind = .file_outside_module_root,
                     });
                     _ = zcu.alive_files.pop(); // we failed to populate `mod`/`sub_file_path`
                 },