From baf2db5cb7c204efa6a97decd8b324130bd82f15 Mon Sep 17 00:00:00 2001
From: Marek Safar <marek.safar@gmail.com>
Date: Tue, 19 Apr 2016 19:14:44 +0200
Subject: [PATCH] [mcs] Don't do empty array interpolation on user code, weird
 code expects empty array not to be equal

---
 mcs/mcs/cs-parser.jay        |  4 +++-
 mcs/mcs/expression.cs        |  4 +++-
 mcs/tests/test-934.cs        | 22 ++++++++++++++++++++++
 mcs/tests/ver-il-net_4_x.xml | 20 +++++++++++++++-----
 4 files changed, 43 insertions(+), 7 deletions(-)
 create mode 100644 mcs/tests/test-934.cs

diff --git a/mcs/mcs/cs-parser.jay b/mcs/mcs/cs-parser.jay
index b0c771f7207..6783a7edbb6 100644
--- a/mcs/mcs/cs-parser.jay
+++ b/mcs/mcs/cs-parser.jay
@@ -3926,7 +3926,9 @@ array_creation_expression
 	  	if ($4 == null)
 	  		report.Error (1586, GetLocation ($1), "Array creation must have array size or array initializer");
 
-		$$ = new ArrayCreation ((FullNamedExpression) $2, (ComposedTypeSpecifier) $3, (ArrayInitializer) $4, GetLocation ($1));
+		$$ = new ArrayCreation ((FullNamedExpression) $2, (ComposedTypeSpecifier) $3, (ArrayInitializer) $4, GetLocation ($1)) {
+			NoEmptyInterpolation = true
+		};
 	  }
 	| NEW rank_specifier array_initializer
 	  {
diff --git a/mcs/mcs/expression.cs b/mcs/mcs/expression.cs
index 76bcdbfa0ee..b011b264250 100644
--- a/mcs/mcs/expression.cs
+++ b/mcs/mcs/expression.cs
@@ -7862,6 +7862,8 @@ namespace Mono.CSharp
 		{
 		}
 
+		public bool NoEmptyInterpolation { get; set; }
+
 		public ComposedTypeSpecifier Rank {
 			get {
 				return this.rank;
@@ -8398,7 +8400,7 @@ namespace Mono.CSharp
 
 		public override void Emit (EmitContext ec)
 		{
-			if (EmitOptimizedEmpty (ec))
+			if (!NoEmptyInterpolation && EmitOptimizedEmpty (ec))
 				return;
 
 			var await_field = EmitToFieldSource (ec);
diff --git a/mcs/tests/test-934.cs b/mcs/tests/test-934.cs
new file mode 100644
index 00000000000..ba464e35e49
--- /dev/null
+++ b/mcs/tests/test-934.cs
@@ -0,0 +1,22 @@
+class X
+{
+	public static int Main ()
+	{
+		var a = new byte[] { };
+		var b = new byte[] { };
+		if (a.Equals (b))
+			return 1;
+
+		if (ReferenceEquals (a, b))
+			return 2;
+
+		b = new byte[0];
+		if (a.Equals (b))
+			return 3;
+
+		if (ReferenceEquals (a, b))
+			return 4;
+
+		return 0;
+	}
+}
\ No newline at end of file
diff --git a/mcs/tests/ver-il-net_4_x.xml b/mcs/tests/ver-il-net_4_x.xml
index 30bf5ea7293..a395cb4cf76 100644
--- a/mcs/tests/ver-il-net_4_x.xml
+++ b/mcs/tests/ver-il-net_4_x.xml
@@ -10586,7 +10586,7 @@
     </type>
     <type name="ExtensibleTester`1[U]">
       <method name="Void Direct()" attrs="134">
-        <size>24</size>
+        <size>25</size>
       </method>
       <method name="Void .ctor(U)" attrs="6278">
         <size>15</size>
@@ -14348,7 +14348,7 @@
     </type>
     <type name="TestIssue.Program">
       <method name="Int32 Main()" attrs="150">
-        <size>31</size>
+        <size>32</size>
       </method>
       <method name="Void .ctor()" attrs="6278">
         <size>7</size>
@@ -14936,7 +14936,7 @@
         <size>7</size>
       </method>
       <method name="Int32 Main()" attrs="150">
-        <size>36</size>
+        <size>37</size>
       </method>
       <method name="Void .ctor()" attrs="6278">
         <size>7</size>
@@ -43639,7 +43639,7 @@
   <test name="test-555.cs">
     <type name="Test">
       <method name="Int32 Main()" attrs="150">
-        <size>360</size>
+        <size>361</size>
       </method>
       <method name="Void .ctor()" attrs="6278">
         <size>7</size>
@@ -52042,6 +52042,16 @@
       </method>
     </type>
   </test>
+  <test name="test-934.cs">
+    <type name="X">
+      <method name="Int32 Main()" attrs="150">
+        <size>106</size>
+      </method>
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+  </test>
   <test name="test-94.cs">
     <type name="Base">
       <method name="Int32 IVehicle.Start()" attrs="481">
@@ -68791,7 +68801,7 @@
         <size>14</size>
       </method>
       <method name="Boolean MoveNext()" attrs="486">
-        <size>167</size>
+        <size>168</size>
       </method>
       <method name="Void Dispose()" attrs="486">
         <size>15</size>
-- 
2.25.1