From 727233c9c5c1d81d13527f74b0a640f546f28a6c Mon Sep 17 00:00:00 2001
From: Daniel Murphy <yebblies@gmail.com>
Date: Tue, 27 Jan 2015 21:35:32 +1100
Subject: [PATCH] Fix Issue 4733 - Possible bugs caused by dynamic arrays in
 boolean evaluation context

Turn it into a warning
---
 src/expression.c                 |  5 +++++
 test/fail_compilation/warn4733.d | 28 ++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 test/fail_compilation/warn4733.d

diff --git a/src/expression.c b/src/expression.c
index b654d4a2dc0f..c15c4f6c8b91 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -2662,6 +2662,11 @@ Expression *Expression::checkToBoolean(Scope *sc)
             error("expression %s of type %s does not have a boolean value", toChars(), t->toChars());
         return new ErrorExp();
     }
+
+    if (tb->ty == Tarray)
+        warning("implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: %s !is null, %s.length, or %s.ptr instead",
+            toChars(), toChars(), toChars());
+
     return e;
 }
 
diff --git a/test/fail_compilation/warn4733.d b/test/fail_compilation/warn4733.d
new file mode 100644
index 000000000000..368a25923f24
--- /dev/null
+++ b/test/fail_compilation/warn4733.d
@@ -0,0 +1,28 @@
+/*
+REQUIRED_ARGS: -w
+PERMUTE_ARGS:
+TEST_OUTPUT:
+---
+fail_compilation/warn4733.d(20): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(21): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(22): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(23): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(24): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(25): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(26): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+fail_compilation/warn4733.d(27): Warning: implicit conversion of dynamic arrays to bool can be ambiguous and will be deprecated. Use one of: arr !is null, arr.length, or arr.ptr instead
+---
+*/
+
+void main()
+{
+    int[] arr;
+    assert(arr);
+    assert(!arr);
+    assert(arr || 0);
+    assert(arr && 1);
+    assert(arr ? true : false);
+    do {} while(arr);
+    for (; arr;) {}
+    if (arr) {}
+}