diff --git a/codeOptimizers/src/prog8/optimizer/UnusedCodeRemover.kt b/codeOptimizers/src/prog8/optimizer/UnusedCodeRemover.kt
index 0ae7ac634..98ce098eb 100644
--- a/codeOptimizers/src/prog8/optimizer/UnusedCodeRemover.kt
+++ b/codeOptimizers/src/prog8/optimizer/UnusedCodeRemover.kt
@@ -115,11 +115,7 @@ class UnusedCodeRemover(private val program: Program,
                     // if all usages are just an assignment to this vardecl,
                     // and it is in regular RAM, then remove the var as well including all assignments
                     val assignTargets = usages.mapNotNull {
-                        if(it.parent is AssignTarget)
-                                it.parent as AssignTarget
-                        else if(it.parent.parent is AssignTarget)
-                                it.parent.parent as AssignTarget
-                        else null
+                        it.parent as? AssignTarget
                     }.filter {
                         !it.isIOAddress(compTarget.machine)
                     }
diff --git a/compiler/test/TestMemory.kt b/compiler/test/TestMemory.kt
index 8bf7bde4f..4890b0947 100644
--- a/compiler/test/TestMemory.kt
+++ b/compiler/test/TestMemory.kt
@@ -133,7 +133,7 @@ class TestMemory: FunSpec({
         target.isIOAddress(C64Target.machine) shouldBe true
     }
 
-    test("memory expression mapped to IO memory on C64\"") {
+    test("memory expression mapped to IO memory on C64") {
         var memexpr = PrefixExpression("+", NumericLiteralValue.optimalInteger(0x1000, Position.DUMMY), Position.DUMMY)
         var target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
         var assign = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
diff --git a/compiler/test/TestOptimization.kt b/compiler/test/TestOptimization.kt
index 6b04c52ae..a3c874f54 100644
--- a/compiler/test/TestOptimization.kt
+++ b/compiler/test/TestOptimization.kt
@@ -14,7 +14,6 @@ import prog8.ast.base.Position
 import prog8.ast.expressions.*
 import prog8.ast.statements.*
 import prog8.compiler.BeforeAsmGenerationAstChanger
-import prog8.compiler.printAst
 import prog8.compiler.target.C64Target
 import prog8.compilerinterface.*
 import prog8tests.helpers.DummyFunctions
@@ -26,7 +25,7 @@ import prog8tests.helpers.compileText
 import prog8tests.helpers.generateAssembly
 
 class TestOptimization: FunSpec({
-    test("testRemoveEmptySubroutineExceptStart") {
+    test("remove empty subroutine except start") {
         val sourcecode = """
             main {
                 sub start() {
@@ -49,7 +48,7 @@ class TestOptimization: FunSpec({
         }
     }
 
-    test("testDontRemoveEmptySubroutineIfItsReferenced") {
+    test("don't remove empty subroutine if it's referenced") {
         val sourcecode = """
             main {
                 sub start() {
@@ -74,7 +73,7 @@ class TestOptimization: FunSpec({
         }
     }
 
-    test("testGeneratedConstvalueInheritsProperParentLinkage") {
+    test("generated constvalue inherits proper parent linkage") {
         val number = NumericLiteralValue(DataType.UBYTE, 11.0, Position.DUMMY)
         val tc = TypecastExpression(number, DataType.BYTE, false, Position.DUMMY)
         val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
@@ -89,7 +88,7 @@ class TestOptimization: FunSpec({
         tc shouldBeSameInstanceAs constvalue.parent
     }
 
-    test("testConstantFoldedAndSilentlyTypecastedForInitializerValues") {
+    test("constantfolded and silently typecasted for initializervalues") {
         val sourcecode = """
             main {
                 sub start() {
@@ -382,12 +381,11 @@ class TestOptimization: FunSpec({
             }
         """
 
-        // TODO fix this problem!
-
         val result = compileText(C64Target, optimize=true, src, writeAssembly=false).assertSuccess()
-        printAst(result.program)
         val stmts = result.program.entrypoint.statements
-        stmts.size shouldBe 5
+        stmts.size shouldBe 6
+        val assign=stmts.last() as Assignment
+        (assign.target.memoryAddress?.addressExpression as IdentifierReference).nameInSource shouldBe listOf("aa")
     }
 
     test("don't optimize memory writes away") {
@@ -400,33 +398,29 @@ class TestOptimization: FunSpec({
                 }
             }
         """
-
-        // TODO fix this problem!
-
         val result = compileText(C64Target, optimize=true, src, writeAssembly=false).assertSuccess()
-        printAst(result.program)
         val stmts = result.program.entrypoint.statements
-        stmts.size shouldBe 5
+        stmts.size shouldBe 6
+        val assign=stmts.last() as Assignment
+        (assign.target.memoryAddress?.addressExpression as IdentifierReference).nameInSource shouldBe listOf("aa")
     }
 
     test("correctly process constant prefix numbers") {
         val src="""
             main {
                 sub start()  {
-                    byte z1 = 1
-                    byte z2 = +1
-                    byte z3 = ~1
-                    byte z4 = not 1
-                    byte z5 = - 1
+                    ubyte @shared z1 = 1
+                    ubyte @shared z2 = +1
+                    ubyte @shared z3 = ~1
+                    ubyte @shared z4 = not 1
+                    byte @shared z5 = - 1
                 }
             }
         """
-
-        // TODO fix this problem!
-
         val result = compileText(C64Target, optimize=true, src, writeAssembly=false).assertSuccess()
-        printAst(result.program)
         val stmts = result.program.entrypoint.statements
-        stmts.size shouldBe 2
+        stmts.size shouldBe 10
+        stmts.filterIsInstance<VarDecl>().size shouldBe 5
+        stmts.filterIsInstance<Assignment>().size shouldBe 5
     }
 })
diff --git a/compilerAst/src/prog8/ast/statements/AstStatements.kt b/compilerAst/src/prog8/ast/statements/AstStatements.kt
index 85cebf2e7..97d0c6c9c 100644
--- a/compilerAst/src/prog8/ast/statements/AstStatements.kt
+++ b/compilerAst/src/prog8/ast/statements/AstStatements.kt
@@ -434,7 +434,7 @@ data class AssignTarget(var identifier: IdentifierReference?,
         return when {
             identifier != null -> identifier!!.copy()
             arrayindexed != null -> arrayindexed!!.copy()
-            memoryAddress != null -> DirectMemoryRead(memoryAddress.addressExpression, memoryAddress.position)
+            memoryAddress != null -> DirectMemoryRead(memoryAddress.addressExpression.copy(), memoryAddress.position)
             else -> throw FatalAstException("invalid assignmenttarget $this")
         }
     }
diff --git a/compilerAst/test/TestProg8Parser.kt b/compilerAst/test/TestProg8Parser.kt
index 6eba78f75..4d767a36e 100644
--- a/compilerAst/test/TestProg8Parser.kt
+++ b/compilerAst/test/TestProg8Parser.kt
@@ -725,7 +725,7 @@ class TestProg8Parser: FunSpec( {
     }
 
 
-    test("assignment isAugmented correctness") {
+    xtest("assignment isAugmented correctness") {
         val src = SourceCode.Text("""
             main {
                 sub start() {