better error message for ambiguous multi-var initialization in vardecl

compiler/src/prog8/compiler/astprocessing/LiteralsToAutoVars.kt

@@ -74,6 +74,13 @@ internal class LiteralsToAutoVars(private val program: Program, private val erro
 
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         if(decl.names.size>1) {
+
+            val fcallTarget = (decl.value as? IFunctionCall)?.target?.targetSubroutine(program)
+            if(fcallTarget!=null && fcallTarget.returntypes.size>1) {
+                errors.err("ambiguous multi-variable initialization. Use separate variable declaration and assignment(s) instead.", decl.value!!.position)
+                return noModifications
+            }
+
             // note: the desugaring of a multi-variable vardecl has to be done here
             // and not in CodeDesugarer, that one is too late (identifiers can't be found otherwise)
             if(decl.datatype !in NumericDatatypesWithBoolean)

docs/source/todo.rst

@@ -1,8 +1,6 @@
 TODO
 ====
 
-can we make ubyte x,y = cbm.SCREEN() work?  (sugar for  ubyte x,y //  x,y=cbm.SCREEN() ?)
-
 ...
 
 

examples/test.p8

@@ -4,8 +4,12 @@
 
 main {
     sub start() {
-        ubyte @shared x,y,z
-        ubyte @shared k,l,m = 42
-        uword @shared r,s,t = sys.progend()
+        ubyte @shared x,y = multi()
+    }
+
+    asmsub multi() -> ubyte @A, ubyte @Y {
+        %asm {{
+            rts
+        }}
     }
 }