diff --git a/Makefile b/Makefile
index 680265780..e9e8c2f26 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ endif
 SFLAGS += -Ilib -I.
 
 # Flags - Building options
-SFLAGS += -Wall
+SFLAGS += -Wall -Werror
 
 # Flags - Optimizations
 ifeq ($(DEBUG),1)
diff --git a/app/app.cpp b/app/app.cpp
index ae9513046..6a86d4cd6 100644
--- a/app/app.cpp
+++ b/app/app.cpp
@@ -96,9 +96,6 @@ void interactive_expression_parsing() {
       if (index < 0) {
         index = 0;
       }
-      for(int i(0); i<(1<<30); i++) {
-        asm("nop");
-      }
     } else if (character == RIGHT_ARROW_KEY) {
         if (index < max) {
           index++;
diff --git a/kandinsky/test/set_pixel.c b/kandinsky/test/set_pixel.c
index d20028fd4..09a436674 100644
--- a/kandinsky/test/set_pixel.c
+++ b/kandinsky/test/set_pixel.c
@@ -2,5 +2,4 @@
 #include <kandinsky.h>
 
 QUIZ_CASE(setpixel) {
-  2+2;
 }
diff --git a/poincare/src/layout/horizontal_layout.cpp b/poincare/src/layout/horizontal_layout.cpp
index ea816aa73..e1297a0d2 100644
--- a/poincare/src/layout/horizontal_layout.cpp
+++ b/poincare/src/layout/horizontal_layout.cpp
@@ -5,15 +5,11 @@ extern "C" {
 #include "horizontal_layout.h"
 #include "string_layout.h"
 
-static inline KDCoordinate max(KDCoordinate a, KDCoordinate b) {
-  return (a > b ? a : b);
-}
-
 HorizontalLayout::HorizontalLayout(ExpressionLayout * parent, Expression * left_expression, char symbol, Expression * right_expression) :
 ExpressionLayout(parent ) {
   m_children[0] = left_expression->createLayout(this);
 
-  char string[2] = {symbol, NULL};
+  char string[2] = {symbol, '\0'};
   m_children[1] = new StringLayout(this, string, 1);
 
   m_children[2] = right_expression->createLayout(this);
diff --git a/poincare/test/integer.cpp b/poincare/test/integer.cpp
index 082276189..758f2137a 100644
--- a/poincare/test/integer.cpp
+++ b/poincare/test/integer.cpp
@@ -37,7 +37,7 @@ QUIZ_CASE(poincare_integer_subtract) {
 
 QUIZ_CASE(poincare_integer_multiply) {
   assert(Integer(12) * Integer(34) == Integer(408));
-  assert(Integer(56) * Integer(0) == Integer(0));
+  assert(Integer(56) * Integer("0") == Integer("0"));
   assert(Integer(-12) * Integer(34) == Integer(-408));
   assert(Integer(-12) * Integer(-34) == Integer(408));
   assert(Integer(999999) * Integer(999999) == Integer("999998000001"));