fixed missing type checking in vardecl initializer values. Fixes #29

Also fix wrong assert of 0 const check in assembly gen for if-statement comparisons.

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -194,7 +194,9 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
             return listOf(IAstModification.ReplaceNode(ifStatement.condition, booleanExpr, ifStatement))
         }
 
-        if((binExpr.left as? NumericLiteralValue)?.number==0)
+        if((binExpr.operator=="==" || binExpr.operator=="!=") &&
+            (binExpr.left as? NumericLiteralValue)?.number==0 &&
+            (binExpr.right as? NumericLiteralValue)?.number!=0)
             throw CompilerException("if 0==X should have been swapped to if X==0")
 
         // split the conditional expression into separate variables if the operand(s) is not simple.

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

@@ -409,7 +409,7 @@ internal class AstChecker(private val program: Program,
             if(targetDt.typeOrElse(DataType.STRUCT) in IterableDatatypes)
                 errors.err("cannot assign value to string or array", assignment.value.position)
             else if(!(valueDt.istype(DataType.STR) && targetDt.istype(DataType.UWORD)))
-                errors.err("value's type doesn't match target", assignment.value.position)
+                errors.err("type of value doesn't match target", assignment.value.position)
         }
 
         if(assignment.value is TypecastExpression) {
@@ -562,7 +562,7 @@ internal class AstChecker(private val program: Program,
                                 }
                                 val memberDt = memberdecl.datatype
                                 if(!checkValueTypeAndRange(memberDt, constValue)) {
-                                    errors.err("struct member value's type is not compatible with member field '${memberdecl.name}'", value.first.position)
+                                    errors.err("type of struct member value is not compatible with member field '${memberdecl.name}'", value.first.position)
                                     return
                                 }
                             }

compiler/src/prog8/compiler/astprocessing/StatementReorderer.kt

@@ -104,6 +104,13 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
     }
 
     override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+
+        // ConstValue <associativeoperator> X -->  X <associativeoperator> ConstValue
+        // (this should be done by the ExpressionSimplifier when optimizing is enabled,
+        //  but the current assembly code generator for IF statements now also depends on it so we do it here regardless of optimization.)
+        if (expr.left.constValue(program) != null && expr.operator in associativeOperators && expr.right.constValue(program) == null)
+            return listOf(IAstModification.SwapOperands(expr))
+
         // when using a simple bit shift and assigning it to a variable of a different type,
         // try to make the bit shifting 'wide enough' to fall into the variable's type.
         // with this, for instance, uword x = 1 << 10  will result in 1024 rather than 0 (the ubyte result).

compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt

@@ -28,6 +28,10 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
                 if(valueDt.typeOrElse(DataType.STRUCT) in IntegerDatatypes && decl.datatype in ArrayDatatypes)
                     return noModifications
 
+                // don't add a typecast if the initializer value is inherently not assignable
+                if(valueDt isNotAssignableTo decl.datatype)
+                    return noModifications
+
                 return listOf(IAstModification.ReplaceNode(
                         declValue,
                         TypecastExpression(declValue, decl.datatype, true, declValue.position),

examples/test.p8

@@ -4,20 +4,11 @@
 
 main {
     sub start() {
-        str anim = "1234"
-        ubyte anim_counter = 0
-
-        test_stack.test()
-
-        txt.print("loading ")
-        repeat 100 {
-            ubyte qq = anim[anim_counter/2]
-            txt.chrout(qq)
-            anim_counter = (anim_counter+1) & 7
+        ubyte xx=99
+        if 0==xx {
+            txt.print("fout")
         }
-        txt.print("done!\n")
-
-        test_stack.test()
+        txt.print("loading ")
     }
 }