diff --git a/ccc.h b/ccc.h
index 7b58b4d..2c491d6 100644
--- a/ccc.h
+++ b/ccc.h
@@ -54,6 +54,7 @@ typedef struct Var Var;
 struct Var {
   char *name;     // Variable name
   Type *ty;       // Type
+  Token *tok;     // for error message
   bool is_local;  // local or global
   // local variable
   int offset;  // Offset from RBP
@@ -173,13 +174,14 @@ typedef enum {
 } TypeKind;
 struct Type {
   TypeKind kind;
-  bool is_typedef;  // typedef
-  bool is_static;   // static
-  int align;        // alignment
-  Type *base;       // pointer or array
-  int array_size;   // array
-  Member *members;  // struct
-  Type *return_ty;  // function
+  bool is_typedef;     // typedef
+  bool is_static;      // static
+  bool is_incomplete;  // incomplete array
+  int align;           // alignment
+  Type *base;          // pointer or array
+  int array_size;      // array
+  Member *members;     // struct
+  Type *return_ty;     // function
 };
 
 // Struct member
@@ -200,7 +202,7 @@ Type *enum_type();
 Type *func_type(Type *return_ty);
 Type *pointer_to(Type *base);
 Type *array_of(Type *base, int size);
-int size_of(Type *ty);
+int size_of(Type *ty, Token *tok);
 void add_type(Program *prog);
 
 //
diff --git a/codegen.c b/codegen.c
index a8b7ccd..1977929 100644
--- a/codegen.c
+++ b/codegen.c
@@ -16,7 +16,7 @@ void truncate(Type *ty) {
     printf("  setne al\n");
   }
 
-  int sz = size_of(ty);
+  int sz = size_of(ty, NULL);
   if (sz == 1) {
     printf("  movsx rax, al\n");
   } else if (sz == 2) {
@@ -64,7 +64,7 @@ void gen_lval(Node *node) {
 
 void load(Type *ty) {
   printf("  pop rax\n");
-  int sz = size_of(ty);
+  int sz = size_of(ty, NULL);
   if (sz == 1) {
     printf("  movsx rax, byte ptr [rax]\n");
   } else if (sz == 2) {
@@ -88,7 +88,7 @@ void store(Type *ty) {
     printf("  movzb rdi, dil\n");
   }
 
-  int sz = size_of(ty);
+  int sz = size_of(ty, NULL);
   if (sz == 1) {
     printf("  mov [rax], dil\n");
   } else if (sz == 2) {
@@ -102,15 +102,17 @@ void store(Type *ty) {
   printf("  push rdi\n");
 }
 
-void inc(Type *ty) {
+void inc(Node *node) {
+  int sz = node->ty->base ? size_of(node->ty->base, node->tok) : 1;
   printf("  pop rax\n");
-  printf("  add rax, %d\n", ty->base ? size_of(ty->base) : 1);
+  printf("  add rax, %d\n", sz);
   printf("  push rax\n");
 }
 
-void dec(Type *ty) {
+void dec(Node *node) {
+  int sz = node->ty->base ? size_of(node->ty->base, node->tok) : 1;
   printf("  pop rax\n");
-  printf("  sub rax, %d\n", ty->base ? size_of(ty->base) : 1);
+  printf("  sub rax, %d\n", sz);
   printf("  push rax\n");
 }
 
@@ -287,21 +289,21 @@ void gen(Node *node) {
       gen_lval(node->lhs);
       printf("  push [rsp]\n");
       load(node->ty);
-      inc(node->ty);
+      inc(node);
       store(node->ty);
       return;
     case ND_PRE_DEC:
       gen_lval(node->lhs);
       printf("  push [rsp]\n");
       load(node->ty);
-      dec(node->ty);
+      dec(node);
       store(node->ty);
       return;
     case ND_POST_INC:
       gen_lval(node->lhs);
       printf("  push [rsp]\n");
       load(node->ty);
-      inc(node->ty);
+      inc(node);
       store(node->ty);
       dec(node->ty);
       return;
@@ -309,7 +311,7 @@ void gen(Node *node) {
       gen_lval(node->lhs);
       printf("  push [rsp]\n");
       load(node->ty);
-      dec(node->ty);
+      dec(node);
       store(node->ty);
       inc(node->ty);
       return;
@@ -327,13 +329,13 @@ void gen(Node *node) {
       switch (node->kind) {
         case ND_A_ADD:
           if (node->ty->base) {
-            printf("  imul rdi, %d\n", size_of(node->ty->base));
+            printf("  imul rdi, %d\n", size_of(node->ty->base, node->tok));
           }
           printf("  add rax, rdi\n");
           break;
         case ND_A_SUB:
           if (node->ty->base) {
-            printf("  imul rdi, %d\n", size_of(node->ty->base));
+            printf("  imul rdi, %d\n", size_of(node->ty->base, node->tok));
           }
           printf("  sub rax, rdi\n");
           break;
@@ -376,13 +378,13 @@ void gen(Node *node) {
   switch (node->kind) {
     case ND_ADD:
       if (node->ty->base) {
-        printf("  imul rdi, %d\n", size_of(node->ty->base));
+        printf("  imul rdi, %d\n", size_of(node->ty->base, node->tok));
       }
       printf("  add rax, rdi\n");
       break;
     case ND_SUB:
       if (node->ty->base) {
-        printf("  imul rdi, %d\n", size_of(node->ty->base));
+        printf("  imul rdi, %d\n", size_of(node->ty->base, node->tok));
       }
       printf("  sub rax, rdi\n");
       break;
@@ -427,7 +429,7 @@ void gen(Node *node) {
 }
 
 void load_arg(Var *var, int idx) {
-  int sz = size_of(var->ty);
+  int sz = size_of(var->ty, var->tok);
   if (sz == 1) {
     printf("  mov [rbp-%d], %s\n", var->offset, argreg1[idx]);
   } else if (sz == 2) {
@@ -446,7 +448,7 @@ void emit_data(Program *prog) {
     Var *var = vl->var;
     printf("%s:\n", var->name);
     if (!var->contents) {
-      printf("  .zero %d\n", size_of(var->ty));
+      printf("  .zero %d\n", size_of(var->ty, var->tok));
       continue;
     }
     for (int i = 0; i < var->cont_len; i++) {
diff --git a/main.c b/main.c
index cd42a78..d613862 100644
--- a/main.c
+++ b/main.c
@@ -37,7 +37,7 @@ int main(int argc, char **argv) {
     for (VarList *vl = fn->locals; vl; vl = vl->next) {
       Var *var = vl->var;
       offset = align_to(offset, var->ty->align);
-      offset += size_of(var->ty);
+      offset += size_of(var->ty, var->tok);
       var->offset = offset;
     }
     fn->stack_size = align_to(offset, 8);
diff --git a/parse.c b/parse.c
index e1888df..a476306 100644
--- a/parse.c
+++ b/parse.c
@@ -19,12 +19,29 @@ struct TagScope {
   Type *ty;
 };
 
+typedef struct {
+  VarScope *var_scope;
+  TagScope *tag_scope;
+} Scope;
+
 VarList *locals;
 VarList *globals;
 
 VarScope *var_scope;
 TagScope *tag_scope;
 
+Scope *enter_scope() {
+  Scope *sc = calloc(1, sizeof(Scope));
+  sc->var_scope = var_scope;
+  sc->tag_scope = tag_scope;
+  return sc;
+}
+
+void leave_scope(Scope *sc) {
+  var_scope = sc->var_scope;
+  tag_scope = sc->tag_scope;
+}
+
 // Find a variable or a typedef by name.
 VarScope *find_var(Token *tok) {
   for (VarScope *sc = var_scope; sc; sc = sc->next) {
@@ -85,11 +102,13 @@ VarScope *push_scope(char *name) {
   return sc;
 }
 
-Var *push_var(char *name, Type *ty, bool is_local) {
+Var *push_var(char *name, Type *ty, bool is_local, Token* tok) {
   Var *var = calloc(1, sizeof(Var));
   var->name = name;
   var->ty = ty;
   var->is_local = is_local;
+  var->tok = tok;
+
   VarList *vl = calloc(1, sizeof(VarList));
   vl->var = var;
   if (is_local) {
@@ -324,13 +343,14 @@ Type *abstract_declarator(Type *ty) {
   return type_suffix(ty);
 }
 
-// type-suffix = ("[" num "]" type-suffix)?
+// type-suffix = ("[" num? "]" type-suffix)?
 Type *type_suffix(Type *ty) {
   if (!consume("[")) {
     return ty;
   }
-  int sz = expect_number();
-  expect("]");
+  
+  int sz = 0;
+  bool is_incomplete = true;
   ty = type_suffix(ty);
   return array_of(ty, sz);
 }