type check tuning

compilerAst/src/prog8/ast/AstToSourceTextConverter.kt

@@ -353,12 +353,13 @@ class AstToSourceTextConverter(val output: (text: String) -> Unit, val program:
 
     override fun visit(assignment: Assignment) {
         val binExpr = assignment.value as? BinaryExpression
-        if(binExpr!=null && assignment.isAugmentable) {
+        if(binExpr!=null && binExpr.left isSameAs assignment.target && binExpr.operator !in ComparisonOperators) {
+            // we only support the inplace assignments of the form A = A <operator> <value>
+            // don't use assignment.isAugmentable here! That one is a more general check, and not suitable for printing the AST like here
             assignment.target.accept(this)
             output(" ${binExpr.operator}= ")
             binExpr.right.accept(this)
         } else {
-            val whyNot = assignment.isAugmentable
             assignment.target.accept(this)
             output(" = ")
             assignment.value.accept(this)

compilerAst/src/prog8/ast/statements/AstStatements.kt

@@ -386,7 +386,7 @@ class StructDecl(override val name: String, val fields: List<Pair<DataType, Stri
     override fun copy() = StructDecl(name, fields.toList(), position)
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
-    fun memsize(sizer: IMemSizer): Int = fields.sumOf { sizer.memorySize(it.first, 1) }
+    override fun memsize(sizer: IMemSizer): Int = fields.sumOf { sizer.memorySize(it.first, 1) }
     fun getFieldType(name: String): DataType? = fields.firstOrNull { it.second==name }?.first
     override val scopedNameString by lazy { scopedName.joinToString(".") }
 }
@@ -503,6 +503,7 @@ class Assignment(var target: AssignTarget, var value: Expression, var origin: As
 
     /**
      * Is the assigment value an expression that references the assignment target itself?
+     * Note it doesn't have to be the first term in the expression!
      * The expression can be a BinaryExpression, PrefixExpression or TypecastExpression (possibly with one sub-cast).
      */
     val isAugmentable: Boolean