From c40fc584d6fc0983ec05e9b1df008daf7aba7813 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Wed, 21 Nov 2018 22:07:13 +0100
Subject: [PATCH] added warning about using X as sub parameter

---
 compiler/examples/test.p8            | 37 +++++++++++-----------------
 compiler/src/prog8/ast/AstChecker.kt |  5 ++++
 2 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/compiler/examples/test.p8 b/compiler/examples/test.p8
index cebdae339..bcebb40aa 100644
--- a/compiler/examples/test.p8
+++ b/compiler/examples/test.p8
@@ -16,33 +16,24 @@ sub start() {
     byte b1
 
 
-    ;v1=foo()
+    address  =c64.MEMBOT(1, 40000.w)   ; ok!
+    address  =c64.MEMBOT(1, address)   ; ok!
+    address  =c64.MEMBOT(1, memaddr)   ; ok!
 
-    ;address  =c64.MEMBOT(1, 40000.w)   ; ok!
-    ;address  =c64.MEMBOT(1, address)   ; ok!
-    ;address  =c64.MEMBOT(1, memaddr)   ; ok!i
-    ;address  =c64.MEMBOT(1, wordarray[1])   ; @todo nice error about loading X register from stack
-
-    ;A, Y =c64.GETADR()      ; ok!
-    ;Y, A =c64.GETADR()      ; ok!
-    ;address = c64flt.GETADRAY() ; ok!
-    ;memaddr = c64flt.GETADRAY() ; ok!
-    ;wordarray[1] = c64flt.GETADRAY() ; ok!
-    ;v1, v2 =c64.GETADR()    ; ok!
-    ;address  =c64.IOBASE() ; ok!
-    ;A = c64.CHRIN()   ; ok !
-    ;X = c64.CHRIN()  ; ok !
-    ;Y = c64.CHRIN()  ; ok!
-    ;v1 = c64.CHRIN()    ; ok !
+    A, Y =c64.GETADR()      ; ok!
+    Y, A =c64.GETADR()      ; ok!
+    address = c64flt.GETADRAY() ; ok!
+    memaddr = c64flt.GETADRAY() ; ok!
+    wordarray[1] = c64flt.GETADRAY() ; ok!
+    v1, v2 =c64.GETADR()    ; ok!
+    address  =c64.IOBASE() ; ok!
+    A = c64.CHRIN()   ; ok !
+    X = c64.CHRIN()  ; ok !
+    Y = c64.CHRIN()  ; ok!
+    v1 = c64.CHRIN()    ; ok !
 
     return
 }
 
 
-sub foo() -> float {
-    return 1            ; @todo fix error: '1' as byte or float literal (not ubyte)
-}
-
-
-
 }
diff --git a/compiler/src/prog8/ast/AstChecker.kt b/compiler/src/prog8/ast/AstChecker.kt
index fd90973b9..6b108ff01 100644
--- a/compiler/src/prog8/ast/AstChecker.kt
+++ b/compiler/src/prog8/ast/AstChecker.kt
@@ -693,6 +693,11 @@ class AstChecker(private val namespace: INameScope,
                 for (arg in args.withIndex().zip(target.parameters)) {
                     if(arg.first.value.resultingDatatype(namespace, heap) != arg.second.type)
                         checkResult.add(ExpressionError("argument ${arg.first.index+1} has invalid type, expected ${arg.second.type}", position))
+
+                    if(target.asmParameterRegisters[arg.first.index].registerOrPair in setOf(RegisterOrPair.AX, RegisterOrPair.XY, RegisterOrPair.X)) {
+                        if(arg.first.value !is LiteralValue && arg.first.value !is IdentifierReference)
+                            printWarning("calling a subroutine that expects X as a parameter is problematic, more so when providing complex arguments. If you see a compiler error/crash about this later, try to simplify this call", position)
+                    }
                 }
             }
         }