Do not emit recursion groups without GC enabled (#4738)

We emit nominal types as a single large recursion group, but this produces
invalid modules when --nominal or --hybrid was used without GC enabled. Fix the
bug by always emitting types as though they were structural (i.e. without
recursion groups) when GC is not enabled.

Fixes #4723.

1 files changed, 20 insertions, 0 deletions

diff --git a/test/lit/nominal-no-gc.wast b/test/lit/nominal-no-gc.wast
new file mode 100644
index 000000000..7247caa5a
--- /dev/null
+++ b/test/lit/nominal-no-gc.wast
@@ -0,0 +1,20 @@
+;; Write the module with --nominal but without GC
+;; RUN: wasm-opt %s --nominal --disable-gc -g -o %t.wasm
+
+;; We should not get any recursion groups even though we used --nominal. We use
+;; --hybrid -all here to make sure that any rec groups from the binary will
+;; actually show up in the output and cause the test to fail.
+;; RUN: wasm-opt %t.wasm --hybrid -all -S -o - | filecheck %s
+
+;; Also check that we don't get a failure with the default configuration.
+;; RUN: wasm-opt %t.wasm
+
+;; CHECK-NOT: rec
+
+(module
+  (type $foo (func))
+  (type $bar (func))
+
+  (func $f1 (type $foo))
+  (func $f2 (type $bar))
+)