avm2: Allow splice() on a Vector with fixed=true

core/src/avm2/vector.rs

@@ -7,7 +7,7 @@ use crate::avm2::value::Value;
 use crate::avm2::Error;
 use gc_arena::Collect;
 use std::cmp::{max, min};
-use std::ops::{Index, RangeBounds};
+use std::ops::RangeBounds;
 use std::slice::SliceIndex;
 
 /// The vector storage portion of a vector object.
@@ -401,10 +401,7 @@ impl<'gc> VectorStorage<'gc> {
     where
         R: Clone + SliceIndex<[Value<'gc>], Output = [Value<'gc>]> + RangeBounds<usize>,
     {
-        if self.is_fixed && self.storage.index(range.clone()).len() != replace_with.len() {
-            return Err("RangeError: Vector is fixed".into());
-        }
-
+        // NOTE: no fixed check here for bug compatibility
         Ok(self.storage.splice(range, replace_with).collect())
     }
 }

tests/tests/swfs/avm2/vector_splice_fixed_bug_compat/Test.as

@@ -0,0 +1,28 @@
+// compiled with mxmlc
+
+import flash.utils.getQualifiedClassName;
+import flash.utils.getTimer;
+import flash.utils.ByteArray;
+
+var v = new Vector.<int>(5, true);
+trace(v.length);
+try {
+    v.push(123);
+} catch(e) {
+    trace("push exception caught");
+}
+v.splice(0, 3);
+trace("NO exception on splice")
+trace(v.length);
+
+package {
+    import flash.display.MovieClip;
+    import flash.text.TextField;
+
+    public class Test extends MovieClip {
+        public function Test(){
+
+        }
+    }
+}
+

tests/tests/swfs/avm2/vector_splice_fixed_bug_compat/output.txt

@@ -0,0 +1,4 @@
+5
+push exception caught
+NO exception on splice
+2

tests/tests/swfs/avm2/vector_splice_fixed_bug_compat/test.toml

@@ -0,0 +1 @@
+num_frames = 1