From 81702717b032cc946b1d71e831abdcc91b13f2c3 Mon Sep 17 00:00:00 2001
From: Mathias Baumann <git@supradigital.org>
Date: Tue, 21 May 2019 14:40:28 +0200
Subject: [PATCH] [Sol -> Yul] Enable function pointer comparison

---
 .../codegen/ir/IRGeneratorForStatements.cpp   |  7 +++++-
 .../viaYul/comparison_functions.sol           | 23 +++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 test/libsolidity/semanticTests/viaYul/comparison_functions.sol

diff --git a/libsolidity/codegen/ir/IRGeneratorForStatements.cpp b/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
index c4e83bc9e..bb89474cb 100644
--- a/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
+++ b/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
@@ -356,7 +356,12 @@ bool IRGeneratorForStatements::visit(BinaryOperation const& _binOp)
 			"\n";
 	else if (TokenTraits::isCompareOp(op))
 	{
-		solUnimplementedAssert(commonType->category() != Type::Category::Function, "");
+		if (auto type = dynamic_cast<FunctionType const*>(commonType))
+		{
+			solAssert(op == Token::Equal || op == Token::NotEqual, "Invalid function pointer comparison!");
+			solAssert(type->kind() != FunctionType::Kind::External, "External function comparison not allowed!");
+		}
+
 		solAssert(commonType->isValueType(), "");
 		bool isSigned = false;
 		if (auto type = dynamic_cast<IntegerType const*>(commonType))
diff --git a/test/libsolidity/semanticTests/viaYul/comparison_functions.sol b/test/libsolidity/semanticTests/viaYul/comparison_functions.sol
new file mode 100644
index 000000000..e2c3ec833
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/comparison_functions.sol
@@ -0,0 +1,23 @@
+contract C {
+	function internal1() internal pure returns (bool) {
+		return true;
+	}
+	function internal2() internal pure returns (bool) {
+		return true;
+	}
+
+	function equal() public pure returns (bool same, bool diff) {
+		same = internal1 == internal1;
+		diff = internal1 == internal2;
+	}
+
+	function unequal() public pure returns (bool same, bool diff) {
+		same = internal1 != internal1;
+		diff = internal1 != internal2;
+	}
+}
+// ====
+// compileViaYul: true
+// ----
+// equal() -> true, false
+// unequal() -> false, true