Improved error message for invalid instructions

src/ast/parseNode.go

@@ -37,6 +37,6 @@ func parseNode(tokens token.List, source []byte, nodes AST) (Node, error) {
 		return &Call{Expression: expr}, nil
 
 	default:
-		return nil, errors.New(&errors.InvalidInstruction{Instruction: expr.Token.Text(source)}, nil, expr.Token.Position)
+		return nil, errors.New(&errors.InvalidInstruction{Instruction: tokens.Text(source)}, nil, tokens[0].Position)
 	}
 }

tests/errors/InvalidInstructionCall.q

@@ -0,0 +1,5 @@
+import sys
+
+main() {
+	sys.write
+}

tests/errors_test.go

@@ -22,7 +22,8 @@ var errs = []struct {
 	{"ExpectedIfBeforeElse2.q", errors.ExpectedIfBeforeElse},
 	{"ExpectedStructName.q", errors.ExpectedStructName},
 	{"ExpectedPackageName.q", errors.ExpectedPackageName},
-	{"InvalidInstructionExpression.q", &errors.InvalidInstruction{Instruction: "+"}},
+	{"InvalidInstructionCall.q", &errors.InvalidInstruction{Instruction: "sys.write"}},
+	{"InvalidInstructionExpression.q", &errors.InvalidInstruction{Instruction: "2+3"}},
 	{"InvalidInstructionIdentifier.q", &errors.InvalidInstruction{Instruction: "abc"}},
 	{"InvalidInstructionNumber.q", &errors.InvalidInstruction{Instruction: "123"}},
 	{"InvalidInstructionString.q", &errors.InvalidInstruction{Instruction: "\"Hello\""}},