diff --git a/src/pk_compiler.c b/src/pk_compiler.c
index 1ef65ae..a5b0d7a 100644
--- a/src/pk_compiler.c
+++ b/src/pk_compiler.c
@@ -224,7 +224,6 @@ typedef enum {
   PREC_TERM,          // + -
   PREC_FACTOR,        // * / %
   PREC_UNARY,         // - ! ~ not
-  PREC_CHAIN_CALL,    // ->
   PREC_CALL,          // ()
   PREC_SUBSCRIPT,     // []
   PREC_ATTRIB,        // .index
@@ -1126,7 +1125,6 @@ static void exprName(Compiler* compiler);
 static void exprOr(Compiler* compiler);
 static void exprAnd(Compiler* compiler);
 
-static void exprChainCall(Compiler* compiler);
 static void exprBinaryOp(Compiler* compiler);
 static void exprUnaryOp(Compiler* compiler);
 
@@ -1165,7 +1163,7 @@ GrammarRule rules[] = {  // Prefix       Infix             Infix Precedence
   /* TK_AMP        */ { NULL,          exprBinaryOp,     PREC_BITWISE_AND },
   /* TK_PIPE       */ { NULL,          exprBinaryOp,     PREC_BITWISE_OR },
   /* TK_CARET      */ { NULL,          exprBinaryOp,     PREC_BITWISE_XOR },
-  /* TK_ARROW      */ { NULL,          exprChainCall,    PREC_CHAIN_CALL },
+  /* TK_ARROW      */   NO_RULE,
   /* TK_PLUS       */ { NULL,          exprBinaryOp,     PREC_TERM },
   /* TK_MINUS      */ { exprUnaryOp,   exprBinaryOp,     PREC_TERM },
   /* TK_STAR       */ { NULL,          exprBinaryOp,     PREC_FACTOR },
@@ -1300,7 +1298,9 @@ static void exprName(Compiler* compiler) {
         compiler->new_local = true;
 
         // Ensure the local variable's index is equals to the stack top index.
-        ASSERT((compiler->stack_size - 1) == index, OOPS);
+        // If the compiler has errors, we cannot and don't have to assert.
+        ASSERT(compiler->has_errors || (compiler->stack_size - 1) == index,
+               OOPS);
 
         // We don't need to call emitStoreVariable (which emit STORE_LOCAL)
         // because the local is already at it's location in the stack, we just
@@ -1408,34 +1408,6 @@ void exprAnd(Compiler* compiler) {
   compiler->is_last_call = false;
 }
 
-static void exprChainCall(Compiler* compiler) {
-  skipNewLines(compiler);
-  parsePrecedence(compiler, (Precedence)(PREC_CHAIN_CALL + 1));
-  emitOpcode(compiler, OP_SWAP); // Swap the data with the function.
-
-  int argc = 1; // The initial data.
-
-  if (match(compiler, TK_LBRACE)) {
-    if (!match(compiler, TK_RBRACE)) {
-      do {
-        skipNewLines(compiler);
-        compileExpression(compiler);
-        skipNewLines(compiler);
-        argc++;
-      } while (match(compiler, TK_COMMA));
-      consume(compiler, TK_RBRACE, "Expected '}' after chain call "
-                                   "parameter list.");
-    }
-  }
-
-  // TODO: ensure argc < 256 (MAX_ARGC) 1byte.
-
-  emitOpcode(compiler, OP_CALL);
-  emitByte(compiler, argc);
-
-  compiler->is_last_call = false;
-}
-
 static void exprBinaryOp(Compiler* compiler) {
   TokenType op = compiler->previous.type;
   skipNewLines(compiler);
@@ -2102,16 +2074,6 @@ static int compileFunction(Compiler* compiler, FuncType fn_type) {
   if (fn_type != FN_NATIVE) {
     compileBlockBody(compiler, BLOCK_FUNC);
 
-    // Tail call optimization disabled at debug mode.
-    if (compiler->options && !compiler->options->debug) {
-      if (compiler->is_last_call) {
-        ASSERT(_FN->opcodes.count >= 3, OOPS); // OP_CALL, argc, OP_POP
-        ASSERT(_FN->opcodes.data[_FN->opcodes.count - 1] == OP_POP, OOPS);
-        ASSERT(_FN->opcodes.data[_FN->opcodes.count - 3] == OP_CALL, OOPS);
-        _FN->opcodes.data[_FN->opcodes.count - 3] = OP_TAIL_CALL;
-      }
-    }
-
     consume(compiler, TK_END, "Expected 'end' after function definition end.");
     compilerExitBlock(compiler); // Parameter depth.
     emitFunctionEnd(compiler);
diff --git a/src/pk_vm.c b/src/pk_vm.c
index b2d6c74..3b5726c 100644
--- a/src/pk_vm.c
+++ b/src/pk_vm.c
@@ -439,32 +439,6 @@ static void* defaultRealloc(void* memory, size_t new_size, void* user_data) {
   return realloc(memory, new_size);
 }
 
-// If failed to resolve it'll return false. Parameter [result] should be points
-// to the string which is the path that has to be resolved and once it resolved
-// the provided result's string's on_done() will be called and, it's string
-// will be updated with the new resolved path string.
-static inline bool resolveScriptPath(PKVM* vm, PkStringPtr* path_string) {
-  if (vm->config.resolve_path_fn == NULL) return true;
-
-  const char* path = path_string->string;
-  PkStringPtr resolved;
-
-  Fiber* fiber = vm->fiber;
-  if (fiber == NULL || fiber->frame_count <= 0) {
-    // fiber == NULL => vm haven't started yet and it's a root script.
-    resolved = vm->config.resolve_path_fn(vm, NULL, path);
-  } else {
-    const Function* fn = fiber->frames[fiber->frame_count - 1].fn;
-    resolved = vm->config.resolve_path_fn(vm, fn->owner->path->data, path);
-  }
-
-  // Done with the last string and update it with the new string.
-  if (path_string->on_done != NULL) path_string->on_done(vm, *path_string);
-  *path_string = resolved;
-
-  return path_string->string != NULL;
-}
-
 // Import and return Script object as Var. If the script is imported and
 // compiled here it'll set [is_new_script] to true otherwise (using the cached
 // script) set to false.
diff --git a/tests/lang/basics.pk b/tests/lang/basics.pk
index ccb7d05..5a52241 100644
--- a/tests/lang/basics.pk
+++ b/tests/lang/basics.pk
@@ -50,6 +50,15 @@ if a and b then assert(false) end
 if a or b then val = 42 else assert(false) end assert(val == 42)
 if get_true() or false then val = 12 end assert(val == 12)
 
+## Newer logical or implementation.
+## a or b  === if (a) return a else return b
+## a and b === if (!a) return a else return b
+a = null; b = [1, 2, 3]
+assert((a or b) == [1, 2, 3]) ## Note == has higher precedence than and/or.
+assert((a and b) == null)
+assert((b or a) == [1, 2, 3])
+assert((a or b) == b or a)
+
 ## Recursive to_string list/map
 l = [1]
 list_append(l, l)
diff --git a/tests/lang/functions.pk b/tests/lang/functions.pk
index a817b60..3bc2efc 100644
--- a/tests/lang/functions.pk
+++ b/tests/lang/functions.pk
@@ -14,14 +14,12 @@ end
 assert(val == 'defined after the call')
 
 ## Chain call tests. (concatenative programming)
-
-def fn1(data) return '[fn1:' + data + ']' end
-def fn2(data, suffix) return '[fn2:' + data + '|' + suffix + ']' end
-def fn3(data) return '[fn3:' + data + ']' end
-
-result = 'data' -> fn1 -> fn2{'suff'} -> fn3
-assert(result == '[fn3:[fn2:[fn1:data]|suff]]')
-
+## Chain call no more supported (unnecessary feature).
+#def fn1(data) return '[fn1:' + data + ']' end
+#def fn2(data, suffix) return '[fn2:' + data + '|' + suffix + ']' end
+#def fn3(data) return '[fn3:' + data + ']' end
+#result = 'data' -> fn1 -> fn2{'suff'} -> fn3
+#assert(result == '[fn3:[fn2:[fn1:data]|suff]]')
 # str_lower(s) function refactored to s.lower attribute.
 #result = ' tEST+InG ' -> str_strip -> str_lower
 #assert(result == 'test+ing')
diff --git a/tests/lang/import.pk b/tests/lang/import.pk
index a784eab..d023488 100644
--- a/tests/lang/import.pk
+++ b/tests/lang/import.pk
@@ -11,7 +11,7 @@ from path import *
 
 import "basics.pk" ## will import all
 import "controlflow.pk" as if_test
-from "functions.pk" import fn1, fn2 as f2, fn3
+from "functions.pk" import f1, f2 as fn2, f3
 
 import "class.pk" as class_
 assert(class_.Vec(42, 3.14).y == 3.14)
diff --git a/tests/lang/toc.pk b/tests/lang/toc.pk
index ef852d9..05e9cd4 100644
--- a/tests/lang/toc.pk
+++ b/tests/lang/toc.pk
@@ -71,6 +71,11 @@ for i in 0..100
   assert(i%2 == f(i))
 end
 
+## The below function caused a bug after compile time stack size calculation
+## bug fixed. Added here to check for regression.
+def h()
+  f() ## <-- Not tail called here (anymore) because it's not returned.
+end
 
 # If we got here, that means all test were passed.
 print('All TESTS PASSED')