diff --git a/compilerAst/src/prog8/compiler/CallGraph.kt b/compilerAst/src/prog8/compiler/CallGraph.kt
index d6ae73abd..60a25226b 100644
--- a/compilerAst/src/prog8/compiler/CallGraph.kt
+++ b/compilerAst/src/prog8/compiler/CallGraph.kt
@@ -56,9 +56,11 @@ class CallGraph(private val program: Program) : IAstVisitor {
     override fun visit(directive: Directive) {
         val thisModule = directive.definingModule
         if (directive.directive == "%import") {
-            val importedModule: Module = program.modules.single { it.name == directive.args[0].name }
-            imports[thisModule] = imports.getValue(thisModule) + importedModule
-            importedBy[importedModule] = importedBy.getValue(importedModule) + thisModule
+            val importedModule = program.modules.singleOrNull { it.name == directive.args[0].name }     // the module may no longer exist at all due to optimizations
+            if(importedModule!=null) {
+                imports[thisModule] = imports.getValue(thisModule) + importedModule
+                importedBy[importedModule] = importedBy.getValue(importedModule) + thisModule
+            }
         }
 
         super.visit(directive)
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 2ad90644e..db1751c16 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -3,6 +3,7 @@ TODO
 
 Petaxian has gameplay problems on the C64 (with and without optimization) , cx16 target is fine.
 (seems unrelated to boolean type changes.  10.1 was still fine.)
+caused by 358215e4ddf408e568ded0d36afce9f0162e21d1  Removed PostIncrDecr
 
 
 ...