errormessage for assignment to str/arrays in ROM

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -686,6 +686,25 @@ internal class AstChecker(private val program: Program,
                 }
             }
         }
+
+
+        fun checkRomTarget(target: AssignTarget) {
+            val idx=target.arrayindexed
+            if(idx!=null) {
+                val decl = idx.arrayvar.targetVarDecl(program)!!
+                if(decl.type!=VarDeclType.MEMORY && decl.zeropage!=ZeropageWish.REQUIRE_ZEROPAGE) {
+                    // memory mapped arrays are assumed to be in RAM. If they're not.... well, POOF
+                    errors.err("cannot assign to an array or string that is located in ROM", assignTarget.position)
+                }
+            }
+        }
+
+        if(compilerOptions.romable) {
+            if (assignTarget.multi != null)
+                assignTarget.multi?.forEach { checkRomTarget(it) }
+            else
+                checkRomTarget(assignTarget)
+        }
     }
 
     override fun visit(addressOf: AddressOf) {

examples/test.p8

@@ -1,19 +1,42 @@
 %import test_stack
 %import textio
-%zeropage dontuse
+%zeropage basicsafe
 %option no_sysinit, romable
 
 main {
 
     sub start()  {
+        str name = "irmen"      ; there a re no memory-mepped strings.
+        ubyte[] array = [11,22,33,44]
+        &ubyte[20] marray = $2000
+        uword @shared pointer = $4000
 
-        ubyte @shared bankno = 10
+        sys.memset($2000, 20, 55)
 
-        extsub @bank bankno $a000 = routine1()
-        extsub @bank 11 $a000 = routine2()
+        txt.print(name)
+        txt.spc()
+        txt.print_ub(array[1])
+        txt.spc()
+        txt.print_ub(marray[1])
+        txt.nl()
 
-        routine1()
-        routine2()
+        name[2] = '!'
+        marray[1] = '!'     ; TODO should be allowed because memory mapped to non-rom area
+        array[1], marray[1] = multi()
 
+        cx16.r0L=1
+        pointer[cx16.r0L] = 99
+
+        txt.print(name)
+        txt.spc()
+        txt.print_ub(array[1])
+        txt.spc()
+        txt.print_ub(marray[1])
+        txt.nl()
+    }
+
+    sub multi() -> ubyte, ubyte {
+        cx16.r0++
+        return 65,66
     }
 }