diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
index 61ee5209592d1b..c071aee30bfe5c 100644
--- a/.github/workflows/mingw.yml
+++ b/.github/workflows/mingw.yml
@@ -69,7 +69,7 @@ jobs:
             test-all-opts: '--name=!/TestObjSpace#test_reachable_objects_during_iteration/'
           - msystem: 'CLANGARM64'
             os: 11-arm
-            test_task: 'test'
+            test_task: 'check'
       fail-fast: false
 
     if: >-
diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index d37dee59ff963c..18a9ef1523ec5d 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -225,17 +225,32 @@ strio_s_allocate(VALUE klass)
  * call-seq:
  *   StringIO.new(string = '', mode = 'r+') -> new_stringio
  *
- * Note that +mode+ defaults to <tt>'r'</tt> if +string+ is frozen.
- *
  * Returns a new \StringIO instance formed from +string+ and +mode+;
- * see {Access Modes}[rdoc-ref:File@Access+Modes]:
+ * the instance should be closed when no longer needed:
  *
- *   strio = StringIO.new # => #<StringIO>
+ *   strio = StringIO.new
+ *   strio.string        # => ""
+ *   strio.closed_read?  # => false
+ *   strio.closed_write? # => false
  *   strio.close
  *
- * The instance should be closed when no longer needed.
+ * If +string+ is frozen, the default +mode+ is <tt>'r'</tt>:
+ *
+ *   strio = StringIO.new('foo'.freeze)
+ *   strio.string        # => "foo"
+ *   strio.closed_read?  # => false
+ *   strio.closed_write? # => true
+ *   strio.close
+ *
+ * Argument +mode+ must be a valid
+ * {Access Mode}[rdoc-ref:File@Access+Modes],
+ * which may be a string or an integer constant:
+ *
+ *   StringIO.new('foo', 'w+')
+ *   StringIO.new('foo', File::RDONLY)
  *
- * Related: StringIO.open (accepts block; closes automatically).
+ * Related: StringIO.open
+ * (passes the \StringIO object to the block; closes the object automatically on block exit).
  */
 static VALUE
 strio_initialize(int argc, VALUE *argv, VALUE self)
@@ -712,7 +727,7 @@ strio_set_lineno(VALUE self, VALUE lineno)
  *   binmode -> self
  *
  * Sets the data mode in +self+ to binary mode;
- * see {Data Mode}[https://docs.ruby-lang.org/en/master/File.html#class-File-label-Data+Mode].
+ * see {Data Mode}[rdoc-ref:File@Data+Mode].
  *
  */
 static VALUE
diff --git a/namespace.c b/namespace.c
index b85cbf57157924..4e5a4e9bc42491 100644
--- a/namespace.c
+++ b/namespace.c
@@ -268,7 +268,7 @@ const rb_data_type_t rb_root_namespace_data_type = {
         namespace_entry_memsize,
         rb_namespace_gc_update_references,
     },
-    0, 0, RUBY_TYPED_FREE_IMMEDIATELY // TODO: enable RUBY_TYPED_WB_PROTECTED when inserting write barriers
+    &rb_namespace_data_type, 0, RUBY_TYPED_FREE_IMMEDIATELY // TODO: enable RUBY_TYPED_WB_PROTECTED when inserting write barriers
 };
 
 VALUE
diff --git a/zjit/src/codegen.rs b/zjit/src/codegen.rs
index 029e144303f999..0a3be9277bb0e8 100644
--- a/zjit/src/codegen.rs
+++ b/zjit/src/codegen.rs
@@ -506,12 +506,9 @@ fn gen_get_ep(asm: &mut Assembler, level: u32) -> Opnd {
 
 fn gen_objtostring(jit: &mut JITState, asm: &mut Assembler, val: Opnd, cd: *const rb_call_data, state: &FrameState) -> Opnd {
     gen_prepare_non_leaf_call(jit, asm, state);
-
-    let iseq_opnd = Opnd::Value(jit.iseq.into());
-
     // TODO: Specialize for immediate types
     // Call rb_vm_objtostring(iseq, recv, cd)
-    let ret = asm_ccall!(asm, rb_vm_objtostring, iseq_opnd, val, (cd as usize).into());
+    let ret = asm_ccall!(asm, rb_vm_objtostring, VALUE(jit.iseq as usize).into(), val, (cd as usize).into());
 
     // TODO: Call `to_s` on the receiver if rb_vm_objtostring returns Qundef
     // Need to replicate what CALL_SIMPLE_METHOD does
@@ -836,16 +833,12 @@ fn gen_setivar(jit: &mut JITState, asm: &mut Assembler, recv: Opnd, id: ID, val:
 
 fn gen_getclassvar(jit: &mut JITState, asm: &mut Assembler, id: ID, ic: *const iseq_inline_cvar_cache_entry, state: &FrameState) -> Opnd {
     gen_prepare_non_leaf_call(jit, asm, state);
-
-    let iseq = asm.load(Opnd::mem(64, CFP, RUBY_OFFSET_CFP_ISEQ));
-    asm_ccall!(asm, rb_vm_getclassvariable, iseq, CFP, id.0.into(), Opnd::const_ptr(ic))
+    asm_ccall!(asm, rb_vm_getclassvariable, VALUE(jit.iseq as usize).into(), CFP, id.0.into(), Opnd::const_ptr(ic))
 }
 
 fn gen_setclassvar(jit: &mut JITState, asm: &mut Assembler, id: ID, val: Opnd, ic: *const iseq_inline_cvar_cache_entry, state: &FrameState) {
     gen_prepare_non_leaf_call(jit, asm, state);
-
-    let iseq = asm.load(Opnd::mem(64, CFP, RUBY_OFFSET_CFP_ISEQ));
-    asm_ccall!(asm, rb_vm_setclassvariable, iseq, CFP, id.0.into(), val, Opnd::const_ptr(ic));
+    asm_ccall!(asm, rb_vm_setclassvariable, VALUE(jit.iseq as usize).into(), CFP, id.0.into(), val, Opnd::const_ptr(ic));
 }
 
 /// Look up global variables