From d84cc2d1229831e35af27401a5fd5c647402b40e Mon Sep 17 00:00:00 2001
From: acqn <acqn163@outlook.com>
Date: Wed, 2 Nov 2022 13:56:55 +0800
Subject: [PATCH] Fixed errors in the conditional operator "? :" parser.

---
 src/cc65/expr.c    | 16 +++++++++-------
 src/cc65/ppexpr.c  |  2 +-
 test/err/bug1893.c |  8 ++++++++
 3 files changed, 18 insertions(+), 8 deletions(-)
 create mode 100644 test/err/bug1893.c

diff --git a/src/cc65/expr.c b/src/cc65/expr.c
index 8c042cc3c..b1c5059bc 100644
--- a/src/cc65/expr.c
+++ b/src/cc65/expr.c
@@ -3869,9 +3869,9 @@ static void hieQuest (ExprDesc* Expr)
 
             ED_FinalizeRValLoad (&Expr2);
         } else {
-            /* Constant boolean subexpression could still have deferred inc/
-            ** dec operations, so just flush their side-effects at this
-            ** sequence point.
+            /* Constant subexpression could still have deferred inc/dec
+            ** operations, so just flush their side-effects at this sequence
+            ** point.
             */
             DoDeferred (SQP_KEEP_NONE, &Expr2);
         }
@@ -3907,7 +3907,7 @@ static void hieQuest (ExprDesc* Expr)
         /* Parse third expression. Remember for later if it is a NULL pointer
         ** expression, then load it into the primary.
         */
-        ExprWithCheck (hie1, &Expr3);
+        ExprWithCheck (hieQuest, &Expr3);
         Expr3IsNULL = ED_IsNullPtr (&Expr3);
         if (!IsTypeVoid (Expr3.Type)    &&
             ED_YetToLoad (&Expr3)       &&
@@ -3920,9 +3920,9 @@ static void hieQuest (ExprDesc* Expr)
 
             ED_FinalizeRValLoad (&Expr3);
         } else {
-            /* Constant boolean subexpression could still have deferred inc/
-            ** dec operations, so just flush their side-effects at this
-            ** sequence point.
+            /* Constant subexpression could still have deferred inc/dec
+            ** operations, so just flush their side-effects at this sequence
+            ** point.
             */
             DoDeferred (SQP_KEEP_NONE, &Expr3);
         }
@@ -4036,6 +4036,8 @@ static void hieQuest (ExprDesc* Expr)
             } else {
                 *Expr = Expr3;
             }
+            /* The result expression is always an rvalue */
+            ED_MarkExprAsRVal (Expr);
         }
 
         /* Setup the target expression */
diff --git a/src/cc65/ppexpr.c b/src/cc65/ppexpr.c
index dd129ced9..0942dc8f8 100644
--- a/src/cc65/ppexpr.c
+++ b/src/cc65/ppexpr.c
@@ -752,7 +752,7 @@ static void PPhieQuest (PPExpr* Expr)
 
         /* Parse third expression */
         PPExprInit (&Expr3);
-        PPhie1 (&Expr3);
+        PPhieQuest (&Expr3);
 
         /* Set the result */
         Expr->IVal = Expr->IVal ? Expr2.IVal != 0 : Expr3.IVal != 0;
diff --git a/test/err/bug1893.c b/test/err/bug1893.c
new file mode 100644
index 000000000..455256179
--- /dev/null
+++ b/test/err/bug1893.c
@@ -0,0 +1,8 @@
+/* bug #1893 - Compiler accepts a ternary expression where it shouldn't */
+
+int main(void)
+{
+    int a, b, c;
+    a == 1? b : c = 3;
+    return 0;
+}