From c4cd57533139e92485e9f97a439d9630a4153953 Mon Sep 17 00:00:00 2001
From: Kugel Fuhr <98353208+kugelfuhr@users.noreply.github.com>
Date: Tue, 18 Nov 2025 14:35:29 +0100
Subject: [PATCH 1/2] Fix parsing boolean not (.not/!).

---
 src/ca65/expr.c | 57 +++++++++++++------------------------------------
 1 file changed, 15 insertions(+), 42 deletions(-)

diff --git a/src/ca65/expr.c b/src/ca65/expr.c
index 1391eddbd..cb77d0e1d 100644
--- a/src/ca65/expr.c
+++ b/src/ca65/expr.c
@@ -146,7 +146,7 @@ static void FreeExprNode (ExprNode* E)
 
 
 
-static ExprNode* Expr0 (void);
+static ExprNode* Expr1 (void);
 
 
 
@@ -1106,6 +1106,18 @@ static ExprNode* Factor (void)
             NextTok ();
             break;
 
+        case TOK_BOOLNOT:
+            NextTok ();
+            L = Expr1 ();
+            if (IsEasyConst (L, &Val)) {
+                FreeExpr (L);
+                N = GenLiteralExpr (!Val);
+            } else {
+                N = NewExprNode (EXPR_BOOLNOT);
+                N->Left = L;
+            }
+            break;
+
         case TOK_PLUS:
             NextTok ();
             N = Factor ();
@@ -1159,7 +1171,7 @@ static ExprNode* Factor (void)
 
         case TOK_LPAREN:
             NextTok ();
-            N = Expr0 ();
+            N = Expr1 ();
             ConsumeRParen ();
             break;
 
@@ -1652,51 +1664,12 @@ static ExprNode* Expr1 (void)
 
 
 
-static ExprNode* Expr0 (void)
-/* Boolean operators: NOT */
-{
-    ExprNode* Root;
-
-    /* Handle booleans */
-    if (CurTok.Tok == TOK_BOOLNOT) {
-
-        long Val;
-        ExprNode* Left;
-
-        /* Skip the operator token */
-        NextTok ();
-
-        /* Read the argument */
-        Left = Expr0 ();
-
-        /* If the argument is const, evaluate it directly */
-        if (IsEasyConst (Left, &Val)) {
-            FreeExpr (Left);
-            Root = GenLiteralExpr (!Val);
-        } else {
-            Root = NewExprNode (EXPR_BOOLNOT);
-            Root->Left = Left;
-        }
-
-    } else {
-
-        /* Read left hand side */
-        Root = Expr1 ();
-
-    }
-
-    /* Return the expression tree we've created */
-    return Root;
-}
-
-
-
 ExprNode* Expression (void)
 /* Evaluate an expression, build the expression tree on the heap and return
 ** a pointer to the root of the tree.
 */
 {
-    return Expr0 ();
+    return Expr1 ();
 }
 
 

From 1924e4cc6340a2f2fdcf4153986ad7b04d9e39d3 Mon Sep 17 00:00:00 2001
From: Kugel Fuhr <98353208+kugelfuhr@users.noreply.github.com>
Date: Tue, 18 Nov 2025 14:36:16 +0100
Subject: [PATCH 2/2] Added a test for #2859.

---
 test/asm/val/bug2859.s | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 test/asm/val/bug2859.s

diff --git a/test/asm/val/bug2859.s b/test/asm/val/bug2859.s
new file mode 100644
index 000000000..cb26191be
--- /dev/null
+++ b/test/asm/val/bug2859.s
@@ -0,0 +1,33 @@
+; Tests for the bug reported in #2859. Boolean not had the correct precedence
+; (as specified in the docs) but worked only correctly at the start of a full
+; expression.
+
+; This one assembles ok since ! is at the start
+.if !.defined(__DOCART__) && .defined(__C64__)
+.byte 1
+.endif
+
+; This one assembles too since a parenthesis restarts a full expression
+.if .defined(__C64__) && (!.defined(__DOCART__))
+.byte 2
+.endif
+
+; This one doesn't work since ! is somewhere in between
+.if .defined(__C64__) && !.defined(__DOCART__)
+.byte 3
+.endif
+
+
+        .import _exit
+        .export _main
+
+                 
+; The following code is an indirect test for the precedence of .not.
+; .not has the lowest precedence, so the expression that is loaded into A
+; evaluates to zero. This has of course to be changed when the precedence
+; of .not is changed.
+_main:
+        lda     #.not 0 + 1             ; Means: .not (0 + 1)
+        ldx     #0
+        jmp     _exit
+