diff --git a/src/Makefile b/src/Makefile
index ce91070..7bb962b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,7 +1,7 @@
 
 
 CC = g++
-CFLAGS = -O3 -Ilib/ -I./ -Iparser/ -std=c++11 -pthread
+CFLAGS = -O3 -Ilib/ -I./ -Iparser/ -std=c++11 -pthread -Wall -g
 SOURCES = $(shell find lib/ -name '*.cpp') parser/bison_parser.cpp parser/flex_lexer.cpp parser/SQLParser.cpp
 BUILD_DIR = ../build/
 BIN_DIR = ../bin
diff --git a/src/lib/Expr.cpp b/src/lib/Expr.cpp
index 1aceca9..b9bda87 100644
--- a/src/lib/Expr.cpp
+++ b/src/lib/Expr.cpp
@@ -17,7 +17,7 @@ char* substr(const char* source, int from, int to) {
 
 
 Expr* Expr::makeOpUnary(OperatorType op, Expr* expr) {
-	ALLOC_EXPR(e, kExprOperator);
+	Expr* e = new Expr(kExprOperator);
 	e->op_type = op;
 	e->expr = expr;
 	e->expr2 = NULL;
@@ -27,7 +27,7 @@ Expr* Expr::makeOpUnary(OperatorType op, Expr* expr) {
 
 
 Expr* Expr::makeOpBinary(Expr* expr1, OperatorType op, Expr* expr2) {
-	ALLOC_EXPR(e, kExprOperator);
+	Expr* e = new Expr(kExprOperator);
 	e->op_type = op;
 	e->op_char = 0;
 	e->expr = expr1;
@@ -36,7 +36,7 @@ Expr* Expr::makeOpBinary(Expr* expr1, OperatorType op, Expr* expr2) {
 }
 
 Expr* Expr::makeOpBinary(Expr* expr1, char op, Expr* expr2) {
-	ALLOC_EXPR(e, kExprOperator);
+	Expr* e = new Expr(kExprOperator);
 	e->op_type = SIMPLE_OP;
 	e->op_char = op;
 	e->expr = expr1;
@@ -47,39 +47,39 @@ Expr* Expr::makeOpBinary(Expr* expr1, char op, Expr* expr2) {
 
 
 Expr* Expr::makeLiteral(int64_t val) {
-	ALLOC_EXPR(e, kExprLiteralInt);
+	Expr* e = new Expr(kExprLiteralInt);
 	e->ival = val;
 	return e;
 }
 
 Expr* Expr::makeLiteral(double value) {
-	ALLOC_EXPR(e, kExprLiteralFloat);
+	Expr* e = new Expr(kExprLiteralFloat);
 	e->fval = value;
 	return e;
 }
 
 Expr* Expr::makeLiteral(char* string) {
-	ALLOC_EXPR(e, kExprLiteralString);
+	Expr* e = new Expr(kExprLiteralString);
 	e->name = string;
 	return e;
 }
 
 
 Expr* Expr::makeColumnRef(char* name) {
-	ALLOC_EXPR(e, kExprColumnRef);
+	Expr* e = new Expr(kExprColumnRef);
 	e->name = name;
 	return e;
 }
 
 Expr* Expr::makeColumnRef(char* table, char* name) {
-	ALLOC_EXPR(e, kExprTableColumnRef);
+	Expr* e = new Expr(kExprTableColumnRef);
 	e->name = name;
 	e->table = table;
 	return e;
 }
 
 Expr* Expr::makeFunctionRef(char* func_name, Expr* expr) {
-	ALLOC_EXPR(e, kExprFunctionRef);
+	Expr* e = new Expr(kExprFunctionRef);
 	e->name = func_name;
 	e->expr = expr;
 	return e;
diff --git a/src/lib/Expr.h b/src/lib/Expr.h
index 69348fd..62c5b84 100644
--- a/src/lib/Expr.h
+++ b/src/lib/Expr.h
@@ -91,6 +91,7 @@ struct Expr {
 // Zero initializes an Expr object and assigns it to a space in the heap
 // For Hyrise we still had to put in the explicit NULL constructor
 // http://www.ex-parrot.com/~chris/random/initialise.html
+// Unused
 #define ALLOC_EXPR(var, type) 		\
 	Expr* var;						\
 	do {							\
@@ -98,6 +99,7 @@ struct Expr {
 		var = (Expr*)malloc(sizeof *var);	\
 		*var = zero;				\
 	} while(0);
+#undef ALLOC_EXPR
 
 
 } // namespace hsql
diff --git a/src/lib/SelectStatement.h b/src/lib/SelectStatement.h
index 2ba2a3b..b183e36 100644
--- a/src/lib/SelectStatement.h
+++ b/src/lib/SelectStatement.h
@@ -48,6 +48,7 @@ struct LimitDescription {
 /**
  * @struct SelectStatement
  * Representation of a full select statement.
+ * TODO: add union_order and union_limit
  */
 struct SelectStatement : Statement {
 	SelectStatement() : 
diff --git a/src/parser/flex_lexer.l b/src/parser/flex_lexer.l
index 1f49705..ae7e529 100644
--- a/src/parser/flex_lexer.l
+++ b/src/parser/flex_lexer.l
@@ -35,6 +35,7 @@
 
 /* other flags */
 %option noyywrap
+%option nounput
 %option warn
 %option case-insensitive
 %option prefix="hsql_"
diff --git a/src/sql_grammar_test.cpp b/src/sql_grammar_test.cpp
index 667f300..016eb14 100644
--- a/src/sql_grammar_test.cpp
+++ b/src/sql_grammar_test.cpp
@@ -36,7 +36,7 @@ int main(int argc, char *argv[]) {
 
     bool expect_false = false;
     bool use_file = false;
-    char* file_path;
+    std::string file_path = "";
     
     // Parse command line arguments
     int i = 1;