From 9eb650b2e574483945104ef477de633dd064d42d Mon Sep 17 00:00:00 2001
From: Tobias Reiher <reiher@componolit.com>
Date: Tue, 8 Dec 2020 11:49:45 +0100
Subject: [PATCH] Fix type checking of messages

Ref. #522
---
 rflx/model/message.py            | 17 ++++++++--------
 tests/unit/model/message_test.py | 33 +++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/rflx/model/message.py b/rflx/model/message.py
index b07705486..684ceca84 100644
--- a/rflx/model/message.py
+++ b/rflx/model/message.py
@@ -655,6 +655,7 @@ def __verify_expression_types(self) -> None:
         types: Dict[ID, mty.Type] = {}
 
         def typed_variable(expression: expr.Expr) -> expr.Expr:
+            expression = copy(expression)
             if isinstance(expression, expr.Variable):
                 if expression.name.lower() == "message":
                     expression.type_ = rty.OPAQUE
@@ -683,15 +684,15 @@ def typed_variable(expression: expr.Expr) -> expr.Expr:
                 if l.source in self.types:
                     types[l.source.identifier] = self.types[l.source]
 
-                l.condition = l.condition.substituted(typed_variable)
-                l.size = l.size.substituted(typed_variable)
-                l.first = l.first.substituted(typed_variable)
-
-                for t in [l.condition, l.size, l.first]:
-                    if t == expr.UNDEFINED:
+                for expression in [
+                    l.condition.substituted(typed_variable),
+                    l.size.substituted(typed_variable),
+                    l.first.substituted(typed_variable),
+                ]:
+                    if expression == expr.UNDEFINED:
                         continue
 
-                    error = t.check_type(rty.Any())
+                    error = expression.check_type(rty.Any())
 
                     self.error.extend(error)
 
@@ -700,7 +701,7 @@ def typed_variable(expression: expr.Expr) -> expr.Expr:
                             "on path " + " -> ".join(f.name for f in path),
                             Subsystem.MODEL,
                             Severity.INFO,
-                            t.location,
+                            expression.location,
                         )
 
     def __verify_expressions(self) -> None:
diff --git a/tests/unit/model/message_test.py b/tests/unit/model/message_test.py
index 9f351820c..b9c8823f6 100644
--- a/tests/unit/model/message_test.py
+++ b/tests/unit/model/message_test.py
@@ -679,7 +679,7 @@ def test_subsequent_variable() -> None:
     )
 
 
-def test_reference_to_optional_field() -> None:
+def test_reference_to_optional_field_1() -> None:
     structure = [
         Link(INITIAL, Field("F1")),
         Link(Field("F1"), Field("F2"), Equal(Variable("F1"), TRUE)),
@@ -704,6 +704,37 @@ def test_reference_to_optional_field() -> None:
     )
 
 
+def test_reference_to_optional_field_2() -> None:
+    structure = [
+        Link(INITIAL, Field("Flag")),
+        Link(Field("Flag"), Field("Opt"), Equal(Variable("Flag"), Number(1))),
+        Link(Field("Flag"), Field("Any"), NotEqual(Variable("Flag"), Number(1))),
+        Link(Field("Opt"), Field("Any")),
+        Link(
+            Field("Any"),
+            Field("Data"),
+            size=Mul(
+                Variable("Opt", location=Location((10, 30))), Number(8), location=Location((10, 20))
+            ),
+        ),
+        Link(Field("Data"), FINAL),
+    ]
+    types = {
+        Field("Flag"): MODULAR_INTEGER,
+        Field("Opt"): MODULAR_INTEGER,
+        Field("Any"): MODULAR_INTEGER,
+        Field("Data"): OPAQUE,
+    }
+    assert_message_model_error(
+        structure,
+        types,
+        r"^"
+        r'<stdin>:10:30: model: error: undefined variable "Opt"\n'
+        r"<stdin>:10:20: model: info: on path Flag -> Any -> Data"
+        r"$",
+    )
+
+
 def test_invalid_use_of_size_attribute() -> None:
     structure = [
         Link(INITIAL, Field("F1")),