diff --git a/Changelog.md b/Changelog.md
index 9235ed3a2..5cd4c2f85 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -12,6 +12,7 @@ Bugfixes:
  * Commandline interface: Support ``--evm-version constantinople`` properly.
  * DocString Parser: Fix error message for empty descriptions.
  * Standard JSON: Support ``constantinople`` as ``evmVersion`` properly.
+ * Type System: Improve error message when attempting to shift by a fractional amount.
  * Type System: Make external library functions accessible.
 
 ### 0.4.21 (2018-03-07)
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 41700e283..720215c90 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -327,7 +327,7 @@ bool isValidShiftAndAmountType(Token::Value _operator, Type const& _shiftAmountT
 	else if (IntegerType const* otherInt = dynamic_cast<decltype(otherInt)>(&_shiftAmountType))
 		return !otherInt->isAddress();
 	else if (RationalNumberType const* otherRat = dynamic_cast<decltype(otherRat)>(&_shiftAmountType))
-		return otherRat->integerType() && !otherRat->integerType()->isSigned();
+		return !otherRat->isFractional() && otherRat->integerType() && !otherRat->integerType()->isSigned();
 	else
 		return false;
 }
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index c5abac03c..e5269bc5f 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -5643,6 +5643,16 @@ BOOST_AUTO_TEST_CASE(shift_constant_right_excessive_rvalue)
 	CHECK_ERROR(text, TypeError, "Operator >> not compatible with types int_const 66 and int_const 4294967296");
 }
 
+BOOST_AUTO_TEST_CASE(shift_constant_right_fractional)
+{
+	char const* text = R"(
+		contract C {
+			uint public a = 0x42 >> (1 / 2);
+		}
+	)";
+	CHECK_ERROR(text, TypeError, "Operator >> not compatible with types int_const 66 and rational_const 1 / 2");
+}
+
 BOOST_AUTO_TEST_CASE(inline_assembly_unbalanced_positive_stack)
 {
 	char const* text = R"(