From ee82e1016420d80b68195988fc4a31f164bfd9d8 Mon Sep 17 00:00:00 2001
From: alpharush <0xalpharush@protonmail.com>
Date: Wed, 6 Jul 2022 17:29:16 -0500
Subject: [PATCH] fix argument propagation for .unwrap

---
 slither/slithir/convert.py                         | 14 +++++++++++---
 .../{argument.sol => argument-0.8.9.sol}           |  2 +-
 2 files changed, 12 insertions(+), 4 deletions(-)
 rename tests/ast-parsing/user_defined_value_type/{argument.sol => argument-0.8.9.sol} (86%)

diff --git a/slither/slithir/convert.py b/slither/slithir/convert.py
index 35fc8e11a..ef5cacc16 100644
--- a/slither/slithir/convert.py
+++ b/slither/slithir/convert.py
@@ -400,6 +400,13 @@ def propagate_type_and_convert_call(result, node):
                 ins = new_ins
                 result[idx] = ins
 
+        # If there's two consecutive type conversions, keep only the last
+        # ARG_CALL x                             call_data = [x]
+        # TMP_4 = CONVERT x to Fix               call_data = []
+        # TMP_5 = CONVERT TMP_4 to uint192       call_data = [TMP_5]
+        if isinstance(ins, TypeConversion) and ins.variable in call_data:
+            call_data.remove(ins.variable)
+
         if isinstance(ins, Argument):
             # In case of dupplicate arguments we overwrite the value
             # This can happen because of addr.call.value(1).value(2)
@@ -429,10 +436,10 @@ def propagate_type_and_convert_call(result, node):
             continue
 
         new_ins = propagate_types(ins, node)
-        # Validate that type was propagated
-        if isinstance(new_ins, OperationWithLValue):
-            assert new_ins.lvalue.type
         if new_ins:
+            # Validate that type was propagated
+            if isinstance(new_ins, OperationWithLValue):
+                assert new_ins.lvalue.type
             if isinstance(new_ins, (list,)):
                 for new_ins_ in new_ins:
                     new_ins_.set_node(ins.node)
@@ -1682,6 +1689,7 @@ def convert_constant_types(irs):
                         # TODO: add  POP instruction
                         break
                     types = [p.type for p in func.parameters]
+                assert len(types) == len(ir.arguments)
                 for idx, arg in enumerate(ir.arguments):
                     t = types[idx]
                     if isinstance(t, ElementaryType):
diff --git a/tests/ast-parsing/user_defined_value_type/argument.sol b/tests/ast-parsing/user_defined_value_type/argument-0.8.9.sol
similarity index 86%
rename from tests/ast-parsing/user_defined_value_type/argument.sol
rename to tests/ast-parsing/user_defined_value_type/argument-0.8.9.sol
index 7bdc7d560..55fe237e1 100644
--- a/tests/ast-parsing/user_defined_value_type/argument.sol
+++ b/tests/ast-parsing/user_defined_value_type/argument-0.8.9.sol
@@ -11,7 +11,7 @@ contract FixLib {
         uint256 y = uint192(Fix.unwrap(x));
         return div(y, 1e18);
     }
-    function broken(Fix x) external pure returns (uint256) {
+    function test(Fix x) external pure returns (uint256) {
         return div(uint192(Fix.unwrap(x)), 1e18);
     }
 }