diff --git a/lib/std/zig/AstGen.zig b/lib/std/zig/AstGen.zig
index c865bd92fe1d3d69cf188cf295ba637ef70a0b9f..1408f3c6f037e6e802ce1944764722955faa1fd8 100644
--- a/lib/std/zig/AstGen.zig
+++ b/lib/std/zig/AstGen.zig
@@ -7453,6 +7453,7 @@ fn switchExpr(
                         const ident_name = try astgen.identAsString(ident_token);
                         const ident_name_str = tree.tokenSlice(ident_token);
                         if (mem.eql(u8, "_", ident_name_str)) {
+                            if (non_err_is_ref != .no) return astgen.failTok(payload_token, "pointer modifier invalid on discard", .{});
                             break :scope &scratch_scope.base;
                         }
                         non_err_capture = if (non_err_is_ref != .no) .by_ref else .by_val;
diff --git a/test/cases/compile_errors/capture_by_ref_discard.zig b/test/cases/compile_errors/capture_by_ref_discard.zig
index 1779936d34fc04ef7f29a275886b1e8e47635d10..c407ede6c9dc4ba9a1db6aea344e5b34d06d5871 100644
--- a/test/cases/compile_errors/capture_by_ref_discard.zig
+++ b/test/cases/compile_errors/capture_by_ref_discard.zig
@@ -16,9 +16,14 @@ export fn d() void {
     while (null) |*_| {}
 }
 
+export fn e() void {
+    if (0) |*_| {} else |err| switch (err) {}
+}
+
 // error
 //
 // :2:16: error: pointer modifier invalid on discard
 // :7:18: error: pointer modifier invalid on discard
 // :12:16: error: pointer modifier invalid on discard
 // :16:19: error: pointer modifier invalid on discard
+// :20:13: error: pointer modifier invalid on discard