diff --git a/lslopt/lslparse.py b/lslopt/lslparse.py
index b3df766..e30b5a8 100644
--- a/lslopt/lslparse.py
+++ b/lslopt/lslparse.py
@@ -1791,7 +1791,8 @@ list lazy_list_set(list L, integer i, list v)
                 if AllowStSw is False:
                     raise EParseCantChangeState(self)
                 if AllowStSw is None:
-                    self.SuspiciousStSw.append(self.errorpos)
+                    self.PruneBug.append((self.errorpos,
+                        EParseCantChangeState))
             self.NextToken()
             if self.tok[0] not in ('DEFAULT', 'IDENT'):
                 raise EParseSyntax(self)
@@ -1812,12 +1813,31 @@ list lazy_list_set(list L, integer i, list v)
                 value = None
             else:
                 savepos = self.errorpos
+                saveAllowVoid = self.allowVoid
+                # Needed due to another LSL bug, see regr/void-in-return.lsl
+                self.allowVoid = True
                 value = self.Parse_expression()
+                self.allowVoid = saveAllowVoid
             self.expect(';')
             self.NextToken()
             if ReturnType is None and value is not None:
-                self.errorpos = savepos
-                raise EParseReturnShouldBeEmpty(self)
+                # It follows the same rules as AllowStSw
+                if AllowStSw is False:
+                    self.errorpos = savepos
+                    raise EParseReturnShouldBeEmpty(self)
+                elif value.t is None:
+                    if AllowStSw is None:
+                        self.PruneBug.append((self.errorpos,
+                            EParseReturnShouldBeEmpty))
+                    self.PushScope()
+                    scope = self.scopeindex
+                    self.PopScope()
+                    return nr(nt='{}', t=None, scope=scope,
+                        ch=[nr(nt='EXPR', t=None, ch=[value]),
+                            nr(nt='RETURN', t=None)])
+                else:
+                    self.errorpos = savepos
+                    raise EParseTypeMismatch(self)
             if ReturnType is not None and value is None:
                 self.errorpos = savepos
                 raise EParseReturnIsEmpty(self)
@@ -1835,22 +1855,22 @@ list lazy_list_set(list L, integer i, list v)
             ret.ch.append(self.Parse_expression())
             self.expect(')')
             self.NextToken()
-            saveSuspiciousStSw = self.SuspiciousStSw
-            self.SuspiciousStSw = []
+            savePruneBug = self.PruneBug
+            self.PruneBug = []
             ret.ch.append(self.Parse_statement(ReturnType, AllowStSw = None, InsideLoop = InsideLoop))
             if self.tok[0] == 'ELSE':
-                if AllowStSw is False and self.SuspiciousStSw:
-                    self.errorpos = self.SuspiciousStSw[0]
-                    raise EParseCantChangeState(self)
+                if AllowStSw is False and self.PruneBug:
+                    self.errorpos = self.PruneBug[0][0]
+                    raise self.PruneBug[0][1](self)
                 LastIsReturn = getattr(ret.ch[1], 'LIR', False)
                 self.NextToken()
                 ret.ch.append(self.Parse_statement(ReturnType,
                     AllowStSw = AllowStSw, InsideLoop = InsideLoop))
                 if AllowStSw is None:
-                    saveSuspiciousStSw += self.SuspiciousStSw
+                    savePruneBug += self.PruneBug
                 if LastIsReturn and getattr(ret.ch[2], 'LIR', False):
                     ret.LIR = True
-            self.SuspiciousStSw = saveSuspiciousStSw
+            self.PruneBug = savePruneBug
             return ret
 
         if tok0 == 'WHILE':
@@ -2915,8 +2935,10 @@ list lazy_list_set(list L, integer i, list v)
         # List of preprocessor #line directives.
         self.linedir = []
 
-        # List of positions with suspicious state change statements.
-        self.SuspiciousStSw = []
+        # List of tuples (position, exception) where suspicious state change
+        # statements or returns with void expressions happen. These can only
+        # be detected when the 'else' is found.
+        self.PruneBug = []
 
         # This is a small hack to prevent circular definitions in globals when
         # extended expressions are enabled. When false (default), forward
diff --git a/run-tests.py b/run-tests.py
index 75c8cce..ffda0b8 100755
--- a/run-tests.py
+++ b/run-tests.py
@@ -368,8 +368,19 @@ class UnitTestRegression(UnitTestCase):
         parser.parse('default{timer(){[llDie()];}}')
         parser.parse('default{timer(){llDie();}}')
         parser.parse('default{timer(){(llDie());}}')
-        parser.parse('default{timer(){for(llDie();1;llDie());}}'
-            , ('optimize',))
+        parser.parse('default{timer(){for(llDie();1;llDie());}}',
+            ('optimize',))
+        # 'return <void expr>' works in the same situations as state changes
+        self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
+            'default{timer(){return llDie();}}')
+        self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
+            'default{timer(){if(1)return llDie();else;}}')
+        self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
+            'default{timer(){if(1);else return llDie();}}')
+        self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
+            'default{timer(){return 1;}}')
+        self.assertRaises(lslparse.EParseTypeMismatch, parser.parse,
+            'default{timer(){if(1)return 1;}}')
 
 class UnitTestCoverage(UnitTestCase):
     def test_coverage_misc(self):
diff --git a/unit_tests/regression.suite/void-in-return.lsl b/unit_tests/regression.suite/void-in-return.lsl
new file mode 100644
index 0000000..225b26a
--- /dev/null
+++ b/unit_tests/regression.suite/void-in-return.lsl
@@ -0,0 +1,41 @@
+x(){
+    // All these should work
+    if (1)
+        return llDie();
+    while (1)
+        return llDie();
+    do
+        return llDie();
+    while (1);
+    for (;1;)
+        return llDie();
+    if (1)
+    {
+        return llDie();
+        if (1) return llDie(); else return llDie();
+        return llDie();
+    }
+}
+
+default
+{
+    state_entry()
+    {
+        // Similarly, all these should work
+        if (1)
+            return llDie();
+        while (1)
+            return llDie();
+        do
+            return llDie();
+        while (1);
+        for (;1;)
+            return llDie();
+        if (1)
+        {
+            return llDie();
+            if (1) return llDie(); else return llDie();
+            return llDie();
+        }
+    }
+}
diff --git a/unit_tests/regression.suite/void-in-return.out b/unit_tests/regression.suite/void-in-return.out
new file mode 100644
index 0000000..7a615f8
--- /dev/null
+++ b/unit_tests/regression.suite/void-in-return.out
@@ -0,0 +1,94 @@
+x()
+{
+    if (1)
+    {
+        llDie();
+        return;
+    }
+    while (1)
+    {
+        llDie();
+        return;
+    }
+    do
+    {
+        llDie();
+        return;
+    }
+    while (1);
+    for (; 1; )
+    {
+        llDie();
+        return;
+    }
+    if (1)
+    {
+        {
+            llDie();
+            return;
+        }
+        if (1)
+        {
+            llDie();
+            return;
+        }
+        else
+        {
+            llDie();
+            return;
+        }
+        {
+            llDie();
+            return;
+        }
+    }
+}
+
+default
+{
+    state_entry()
+    {
+        if (1)
+        {
+            llDie();
+            return;
+        }
+        while (1)
+        {
+            llDie();
+            return;
+        }
+        do
+        {
+            llDie();
+            return;
+        }
+        while (1);
+        for (; 1; )
+        {
+            llDie();
+            return;
+        }
+        if (1)
+        {
+            {
+                llDie();
+                return;
+            }
+            if (1)
+            {
+                llDie();
+                return;
+            }
+            else
+            {
+                llDie();
+                return;
+            }
+            {
+                llDie();
+                return;
+            }
+        }
+    }
+}
diff --git a/unit_tests/regression.suite/void-in-return.run b/unit_tests/regression.suite/void-in-return.run
new file mode 100644
index 0000000..91edf6f
--- /dev/null
+++ b/unit_tests/regression.suite/void-in-return.run
@@ -0,0 +1 @@
+main.py - -O -optimize