diff --git a/src/Expr.cc b/src/Expr.cc
index 918e5f1c14..ee855dad70 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -963,10 +963,10 @@ ValPtr BinaryExpr::Fold(Val* v1, Val* v2) const
 			{
 			if ( is_integral )
 				{
-				if ( i1 < 1 )
+				if ( i1 < 0 )
 					RuntimeError("left shifting a negative number is undefined");
 
-				i3 = i1 << i2;
+				i3 = i1 << static_cast<zeek_uint_t>(i2);
 				}
 
 			else if ( is_unsigned )
@@ -979,7 +979,7 @@ ValPtr BinaryExpr::Fold(Val* v1, Val* v2) const
 		case EXPR_RSHIFT:
 			{
 			if ( is_integral )
-				i3 = i1 >> i2;
+				i3 = i1 >> static_cast<zeek_uint_t>(i2);
 
 			else if ( is_unsigned )
 				u3 = u1 >> u2;
diff --git a/testing/btest/bifs/piped_exec.zeek b/testing/btest/bifs/piped_exec.zeek
index c77a74292f..d33f902e5e 100644
--- a/testing/btest/bifs/piped_exec.zeek
+++ b/testing/btest/bifs/piped_exec.zeek
@@ -8,7 +8,7 @@ cmds = string_cat(cmds, "\nprint \"foobar\";");
 # If we're using generated C++, turn that off for the pipe execution,
 # as otherwise we'll get a complaint that there's no corresponding
 # C++ bodies found for that zeek instance.
-if ( piped_exec("export -n ZEEK_USE_CPP; zeek", cmds) != T )
+if ( piped_exec("unset ZEEK_USE_CPP; zeek", cmds) != T )
 	exit(1);
 
 # Test null output.