small fixes per chris's comments

libsolidity/Types.cpp

@@ -26,6 +26,8 @@
 #include <libsolidity/Types.h>
 #include <libsolidity/AST.h>
 
+#include <limits>
+
 using namespace std;
 
 namespace dev
@@ -322,13 +324,11 @@ TypePointer IntegerConstantType::binaryOperatorResult(Token::Value _operator, Ty
 			break;
 		case Token::Exp:
 			if (other.m_value < 0)
-				BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("exponent can't be negative"));
+				return TypePointer();
+			else if (other.m_value > std::numeric_limits<unsigned int>::max())
+				return TypePointer();
 			else
-			{
-				value = boost::multiprecision::powm(m_value, other.m_value, bigint(2) << 256);
-				if (value >= (bigint(1) << 256))
-					BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("exp result overflowed"));
-			}
+				value = boost::multiprecision::pow(m_value, other.m_value.convert_to<unsigned int>());
 			break;
 		default:
 			return TypePointer();

test/SolidityEndToEndTest.cpp

@@ -80,7 +80,7 @@ BOOST_AUTO_TEST_CASE(exp_operator_const_signed)
 {
 	char const* sourceCode = R"(
 		contract test {
-			function f() returns(int d) { return -2 ** 3; }
+			function f() returns(int d) { return (-2) ** 3; }
 		})";
 	compileAndRun(sourceCode);
 	BOOST_CHECK(callContractFunction("f()", bytes()) == toBigEndian(u256(-8)));

test/SolidityNameAndTypeResolution.cpp

@@ -980,16 +980,16 @@ BOOST_AUTO_TEST_CASE(exp_operator_negative_exponent)
 		contract test {
 			function f() returns(uint d) { return 2 ** -3; }
 		})";
-	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), InternalCompilerError);
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
 }
 
-BOOST_AUTO_TEST_CASE(exp_operator_const_overflowed)
+BOOST_AUTO_TEST_CASE(exp_operator_exponent_too_big)
 {
 	char const* sourceCode = R"(
 		contract test {
-			function f() returns(uint d) { return 10 ** 256; }
+			function f() returns(uint d) { return 2 ** 10000000000; }
 		})";
-	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), InternalCompilerError);
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
 }
 
 BOOST_AUTO_TEST_SUITE_END()