nice error message if pop() argument is wrong

codeGeneration/src/prog8/compiler/target/C64Target.kt

@@ -27,7 +27,7 @@ object C64Target: ICompilationTarget {
         if (altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
 
     override fun asmsubArgsEvalOrder(sub: Subroutine): List<Int> = asmsub6502ArgsEvalOrder(sub)
-    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>): Boolean  = asmsub6502ArgsHaveRegisterClobberRisk(args)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>) = asmsub6502ArgsHaveRegisterClobberRisk(args)
 
     override fun memorySize(dt: DataType): Int {
         return when(dt) {

codeGeneration/src/prog8/compiler/target/Cx16Target.kt

@@ -28,7 +28,7 @@ object Cx16Target: ICompilationTarget {
         if (altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
 
     override fun asmsubArgsEvalOrder(sub: Subroutine): List<Int> = asmsub6502ArgsEvalOrder(sub)
-    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>): Boolean  = asmsub6502ArgsHaveRegisterClobberRisk(args)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>) = asmsub6502ArgsHaveRegisterClobberRisk(args)
 
     override fun memorySize(dt: DataType): Int {
         return when(dt) {

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

@@ -981,21 +981,33 @@ internal class AstChecker(private val program: Program,
             checkUnusedReturnValues(functionCallStatement, targetStatement, program, errors)
         }
 
-        if(functionCallStatement.target.nameInSource.last() == "sort") {
+        val funcName = functionCallStatement.target.nameInSource
+
+        if(funcName.size==1) {
+            // check some builtin function calls
+            if(funcName[0] == "sort") {
                 // sort is not supported on float arrays
                 val idref = functionCallStatement.args.singleOrNull() as? IdentifierReference
                 if(idref!=null && idref.inferType(program) istype DataType.ARRAY_F) {
                     errors.err("sorting a floating point array is not supported", functionCallStatement.args.first().position)
                 }
             }
+            else if(funcName[0] in arrayOf("pop", "popw")) {
+                // can only pop into a variable, that has to have the correct type
+                val idref = functionCallStatement.args.singleOrNull() as? IdentifierReference
+                if(idref==null)
+                    errors.err("invalid argument to pop, must be a variable with the correct type: ${functionCallStatement.args.first()}", functionCallStatement.args.first().position)
+            }
 
-        if(functionCallStatement.target.nameInSource.last() in arrayOf("rol", "ror", "rol2", "ror2", "swap", "sort", "reverse")) {
+            if(funcName[0] in arrayOf("rol", "ror", "rol2", "ror2", "swap", "sort", "reverse")) {
                 // in-place modification, can't be done on literals
                 if(functionCallStatement.args.any { it !is IdentifierReference && it !is ArrayIndexedExpression && it !is DirectMemoryRead }) {
                     errors.err("invalid argument to a in-place modifying function", functionCallStatement.args.first().position)
                 }
             }
 
+        }
+
         val error =
             VerifyFunctionArgTypes.checkTypes(functionCallStatement, program)
         if(error!=null) {

docs/source/todo.rst

@@ -6,7 +6,8 @@ For next compiler release (7.4)
 Use GoSub to call subroutines (statements):
     - [DONE] allow separate assigns to subroutine's parameter variables / registers
     - [DONE] turn a regular subroutine call into assignments to the parameters + GoSub (take code from gosub branch)
-    - also do this for asmsubs taking >0 parameters
+    - [DONE] also do this for asmsubs taking >0 parameters
+    - make that push(x+1) doesn't use stack evaluation, via a temp var?
 
 Optimize Function calls in expressions:
     - move args to assignments to params

examples/test.p8

@@ -8,9 +8,9 @@ main {
 
         uword @shared uw
         ubyte @shared ub
+        word @shared ww
 
         push(127)
-        popw(ub)            ; TODO give type error
         pop(ub)
         txt.print_ub(ub)
         txt.nl()