diff --git a/base.cpp b/base.cpp
index c5f9d14..76c77ee 100644
--- a/base.cpp
+++ b/base.cpp
@@ -204,7 +204,7 @@ align_down(size_t size, size_t align){
 }
 
 CORE_Static void
-memory_copy(void *dst, void *src, size_t size){
+memory_copy(void *dst, const void *src, size_t size){
   U8 *d = (U8*)dst;
   U8 *s = (U8*)src;
   for(size_t i = 0; i < size; i++){
diff --git a/base_string.cpp b/base_string.cpp
index 90294d2..2012b29 100644
--- a/base_string.cpp
+++ b/base_string.cpp
@@ -209,26 +209,16 @@ string_builder_make(Allocator *a, S64 first_block_size = 4096){
   return sb;
 }
 
-enum String_Builder_Flag{
-  String_Builder_Flag_None = 0,
-  String_Builder_Flag_AddSize = 0,
-};
-
-CORE_Static String
-string_flatten(Allocator *a, String_Builder *b, String_Builder_Flag flags = String_Builder_Flag_None){
+// @! Make string_flatten a method
+static String string_flatten(Allocator *a, String_Builder *b){
   // @Note(Krzosa): Compute size to allocate
   S64 size = 1;
-  if(is_flag_set(flags, String_Builder_Flag_AddSize)) size += sizeof(size_t);
   For_Linked_List(b->first){
     size += it->len;
   }
 
   String result = {};
   result.str = (U8 *)allocate_size(a, size, false);
-  if(is_flag_set(flags, String_Builder_Flag_AddSize)) {
-    memory_copy(result.str + result.len, &size, sizeof(S64));
-    result.len += sizeof(S64);
-  }
 
   // @Note(Krzosa): Copy the content of each block into the string
   For_Linked_List(b->first){
diff --git a/c3_big_int.cpp b/c3_big_int.cpp
index 115067f..2249fca 100644
--- a/c3_big_int.cpp
+++ b/c3_big_int.cpp
@@ -1,7 +1,6 @@
 // Copyright (c) 2019 Christoffer Lerno. All rights reserved.
 // Use of this source code is governed by the GNU LGPLv3.0 license
 // a copy of which can be found in the LICENSE file.
-#include <string.h>
 
 #define Set_BigInt_Arena(x) BigInt_Arena bigint_allocator(x)
 struct BigInt_Arena{
@@ -55,7 +54,7 @@ bigint_copy(Allocator *allocator, BigInt *src){
   dest.digit_count = src->digit_count;
 
   dest.digits = allocate_array(allocator, uint64_t, dest.digit_count);
-  memcpy(dest.digits, src->digits, sizeof(uint64_t) * dest.digit_count);
+  memory_copy(dest.digits, src->digits, sizeof(uint64_t) * dest.digit_count);
   return dest;
 }
 
@@ -186,7 +185,7 @@ void bigint_init_bigint(BigInt *dest, const BigInt *src)
   dest->is_negative = src->is_negative;
   dest->digit_count = src->digit_count;
   dest->digits = ALLOC_DIGITS(dest->digit_count);
-  memcpy(dest->digits, src->digits, sizeof(uint64_t) * dest->digit_count);
+  memory_copy(dest->digits, src->digits, sizeof(uint64_t) * dest->digit_count);
 }
 
 void bigint_negate(BigInt *dest, const BigInt *source)
@@ -329,7 +328,7 @@ void bigint_init_data(BigInt *dest, const uint64_t *digits, unsigned int digit_c
   dest->digit_count = digit_count;
   dest->is_negative = is_negative;
   dest->digits = ALLOC_DIGITS(digit_count);
-  memcpy(dest->digits, digits, sizeof(uint64_t) * digit_count);
+  memory_copy(dest->digits, digits, sizeof(uint64_t) * digit_count);
 
   normalize(dest);
 }
@@ -344,7 +343,7 @@ void bigint_init_bigfloat(BigInt *dest, const BigFloat *op) {
     if (dest->is_negative) {
         f128M_sub(&zero, &op->value, &abs_val);
     } else {
-        memcpy(&abs_val, &op->value, sizeof(float128_t));
+        memory_copy(&abs_val, &op->value, sizeof(float128_t));
     }
 
     float128_t max_u64;
diff --git a/core_compiler.cpp b/core_compiler.cpp
index 894c258..0f7d212 100644
--- a/core_compiler.cpp
+++ b/core_compiler.cpp
@@ -6,6 +6,7 @@ core_init_compiler(Core_Ctx *ctx, Allocator *allocator) {
 
   ctx->emit_type_info = true;
   ctx->emit_line_directives = true;
+  ctx->debugger_break_on_compiler_error = true;
   ctx->color_codes_enabled = true;
   ctx->same_scope_token = { SAME_SCOPE };
 
diff --git a/core_compiler.h b/core_compiler.h
index 817e66a..dcb8aa3 100644
--- a/core_compiler.h
+++ b/core_compiler.h
@@ -40,6 +40,7 @@ struct Core_Ctx{
 
   Scratch_Arena *scratch;
   Scratch_Arena *stage_arena;
+  String_Builder helper_builder;
 
   int errors_occured;
   int warnings_occured;
@@ -78,8 +79,6 @@ struct Core_Ctx{
   String working_folder;
   List<Token *> files_to_link;
 
-  String_Builder helper_builder;
-
   F64 generating_time_begin;
   F64 generating_time_end;
   F64 resolving_time_begin;
@@ -91,6 +90,7 @@ struct Core_Ctx{
   F64 parsing_time_end;
 
   bool color_codes_enabled;
+  bool debugger_break_on_compiler_error;
 
   // Codegen stage mostly
   S64 indent;
diff --git a/core_compiler_interface.hpp b/core_compiler_interface.hpp
index 69f444c..5bb84dd 100644
--- a/core_compiler_interface.hpp
+++ b/core_compiler_interface.hpp
@@ -635,14 +635,12 @@ struct Core_Message {
   Core_Message *next;
   Core_Message_Kind kind;
   String string;
-  Token *pos1;
-  Token *pos2;
+  Token *tokens[2];
   
   int trace_line;
   char *trace_file;
 };
 
-
 /*
   Array<Token> core_lex_file(Allocator *allocator, char *filename);
   Array<Token> core_lex_string(Allocator *allocator, char *string, size_t size);
diff --git a/core_parsing.cpp b/core_parsing.cpp
index b642c40..5262017 100644
--- a/core_parsing.cpp
+++ b/core_parsing.cpp
@@ -1,16 +1,17 @@
 CORE_Static Ast_Decl *parse_decl(B32 is_global);
 
-static void core_add_message(Core_Message_Kind kind, String string, Token *pos1, Token *pos2 = 0, int line = -1, const char *file = 0) {
+static Core_Message *core_add_message(Core_Message_Kind kind, String string, Token *pos1, Token *pos2 = 0, int line = -1, const char *file = 0) {
   if (kind == CORE_ERROR) pctx->errors_occured += 1;
   if (kind == CORE_WARNING) pctx->warnings_occured += 1;
   Core_Message *message = allocate_struct(pctx->perm, Core_Message);
   message->kind = kind;
   message->string = string;
-  message->pos1 = pos1;
-  message->pos2 = pos2;
+  message->tokens[0] = pos1;
+  message->tokens[1] = pos2;
   message->trace_line = line;
   message->trace_file = (char *)file;
   SLL_QUEUE_ADD(pctx->first_message, pctx->last_message, message);
+  return message;
 }
 
 #define log_trace(...) core_log_trace(__LINE__, __FILE__,##__VA_ARGS__)
@@ -22,80 +23,81 @@ static void core_log_trace(int line, const char *file, const char *str, ...){
 #define PRINTF_GREEN "\033[32m"
 #define PRINTF_RED   "\033[31m"
 #define PRINTF_RESET "\033[0m"
-//
-//CORE_Static void
-//print_token_line(Token *token){
-//  if(!token) return;
-//
-//  // Print from line begin to token
-//  int i1 = token->str - token->line_begin;
-//  log_info_no_nl("%.*s", i1, token->line_begin);
-//
-//  // Print token part
-//  if(pctx->color_codes_enabled){
-//    log_info_no_nl( PRINTF_RED "%.*s" PRINTF_RESET, (int)token->len, token->str);
-//  } else {
-//    log_info_no_nl("%.*s", (int)token->len, token->str);
-//  }
-//
-//
-//  // Print to end of line from token
-//  int iend = 0;
-//  U8 *pointer = token->str + token->len;
-//  while(pointer[iend]!='\n' && pointer[iend]!=0) iend++;
-//  log_info_no_nl("%.*s", iend, pointer);
-//  log_info_no_nl("\n");
-//}
-//
-//CORE_Static void
-//print_token_context(Token *token){
-//  if(!token) return;
-//  log_info_no_nl("\n");
-//  print_token_line(token);
-//}
+
+String core_stringify_message(Core_Ctx *pctx, Allocator *allocator, Core_Message *msg, int color_codes_enabled = false) {
+  String_Builder &b = pctx->helper_builder;
+
+  if (msg->kind == CORE_ERROR) b.addf("Error! ");
+  else if (msg->kind == CORE_WARNING) b.addf("Warning! ");
+  else if (msg->kind == CORE_TRACE) b.addf("Trace: ");
+  else invalid_codepath;
+
+  for (int i = 0; i < buff_cap(msg->tokens); i += 1) {
+    Token *it = msg->tokens[i];
+    if (it) {
+      if (it->kind == TK_Error) {
+        b.addf("%Q |  ", it->error_val);
+      }
+    }
+  }
+
+  b.addf("%Q", msg->string);
+
+  for (int i = 0; i < buff_cap(msg->tokens); i += 1) {
+    Token *token = msg->tokens[i];
+    if (token) {
+      b.addf("\n");
+      // Print from line begin to token
+      int i1 = token->str - token->line_begin;
+      b.addf("%.*s", i1, token->line_begin);
+
+      // Print token part
+      if(color_codes_enabled){
+        b.addf( PRINTF_RED "%.*s" PRINTF_RESET, (int)token->len, token->str);
+      } else {
+        b.addf("%.*s", (int)token->len, token->str);
+      }
+
+      // Print to end of line from token
+      int iend = 0;
+      U8 *pointer = token->str + token->len;
+      while(pointer[iend]!='\n' && pointer[iend]!=0) iend++;
+      b.addf("%.*s", iend, pointer);
+    }
+  }
+
+  for (int i = 0; i < buff_cap(msg->tokens); i += 1) {
+    Token *it = msg->tokens[i];
+    if (it) {
+      b.addf("\n%s:%d", it->file.str, (int)it->line + 1);
+    }
+  }
+
+  String result = string_flatten(allocator, &b);
+  return result;
+}
 
 static void compiler_error(Token *token1, Token *token2, const char *str, ...) {
   STRING_FMT(pctx->perm, str, string);
-  core_add_message(CORE_ERROR, string, token1, token2);
-//  log_info_no_nl("\n%s", string.str);
-//  if(token1){
-//    if(token1->kind == TK_Error){
-//      log_info_no_nl("\nToken Error: %.*s", (int)token1->error_val.len, token1->error_val.str);
-//    }
-//    print_token_context(token1);
-//  }
-//
-//  if(token2){
-//    if(token2->kind == TK_Error){
-//      log_info_no_nl("\nToken Error: %.*s", (int)token2->error_val.len, token2->error_val.str);
-//    }
-//    print_token_context(token2);
-//  }
-//
-//  if(token1) log_info_no_nl("\n%s:%d", token1->file.str, (S32)token1->line + 1);
-//  if(token2) log_info_no_nl("\n%s:%d", token2->file.str, (S32)token2->line + 1);
-//
-//  fflush(stdout);
-  Breakpoint;
+  Core_Message *msg = core_add_message(CORE_ERROR, string, token1, token2);
+  if (pctx->debugger_break_on_compiler_error) {
+    String str = core_stringify_message(pctx, pctx->perm, msg, pctx->color_codes_enabled);
+    printf("%s", str.str); // @! How to get rid of printf ?
+    fflush(stdout);
+    Breakpoint;
+  }
 }
 
 CORE_Static void
 compiler_error(Token *token, const char *str, ...){
   STRING_FMT(pctx->perm, str, string);
-  core_add_message(CORE_ERROR, string, token);
-
-//  if(token) log_info_no_nl("\n%s:%d %Q", token->file.str, (S32)token->line + 1, string);
-//  else log_info_no_nl("\n%s", string.str);
-//  if(token){
-//    if(token->kind == TK_Error){
-//      log_info_no_nl("\nToken Error: %.*s", (int)token->error_val.len, token->error_val.str);
-//    }
-//
-//    print_token_context(token);
-//  }
-  //fflush(stdout);
-
-  Breakpoint;
+  Core_Message *msg = core_add_message(CORE_ERROR, string, token);
+  if (pctx->debugger_break_on_compiler_error) {
+    String str = core_stringify_message(pctx, pctx->perm, msg, pctx->color_codes_enabled);
+    printf("%s", str.str); // @! How to get rid of printf ?
+    fflush(stdout);
+    Breakpoint;
+  }
 }
 
 CORE_Static Token *