diff --git a/src/parser/parse-5-defs.cpp b/src/parser/parse-5-defs.cpp
index 31048176c42..0502c53ad20 100644
--- a/src/parser/parse-5-defs.cpp
+++ b/src/parser/parse-5-defs.cpp
@@ -16,6 +16,8 @@
 
 #include "wat-parser-internal.h"
 
+#include "ir/type-updating.h"
+
 namespace wasm::WATParser {
 
 Result<> parseDefinitions(
@@ -63,6 +65,7 @@ Result<> parseDefinitions(
       if (auto* err = end.getErr()) {
         return ctx.in.err(decls.funcDefs[i].pos, err->msg);
       }
+      TypeUpdating::handleNonDefaultableLocals(f, decls.wasm);
     }
   }
 
diff --git a/src/wasm/wasm-ir-builder.cpp b/src/wasm/wasm-ir-builder.cpp
index 585a1c98f2a..cd83ea72289 100644
--- a/src/wasm/wasm-ir-builder.cpp
+++ b/src/wasm/wasm-ir-builder.cpp
@@ -2302,7 +2302,7 @@ Result<> IRBuilder::makeBrOn(Index label,
     case BrOnCast:
     case BrOnCastDescEq:
       if (out->isNullable()) {
-        resultType = Type(in->getHeapType(), NonNullable);
+        resultType = in->with(NonNullable);
       } else {
         resultType = *in;
       }
diff --git a/test/lit/basic/br-on-cast-extra-values.wast b/test/lit/basic/br-on-cast-extra-values.wast
new file mode 100644
index 00000000000..bed03346ca7
--- /dev/null
+++ b/test/lit/basic/br-on-cast-extra-values.wast
@@ -0,0 +1,17 @@
+;; RUN: wasm-opt %s -all -S -o %t
+;; RUN: wasm-opt %s -all --roundtrip -S -o %t.roundtrip
+
+(module
+  (type $s (struct))
+  (func (param $s (ref $s)) (result (ref $s) (ref $s))
+    local.get $s
+    local.get $s
+    br_on_cast 0 (ref $s) (ref $s)
+  )
+  (func (param $s (ref (exact $s)))
+        (result (ref (exact $s)) (ref null (exact $s)))
+    local.get $s
+    local.get $s
+    br_on_cast 0 (ref (exact $s)) (ref null (exact $s))
+  )
+)