Issue 874: Add detection of unused parameters

CHANGELOG.md

@@ -14,6 +14,10 @@ CLI:
 - `rflx setup_ide` subcommand for installing IDE integration (#795)
 - `rflx` option `--unsafe` (#987)
 
+Model:
+
+- Detection of unused parameters (#874)
+
 ### Changed
 
 Specification:

rflx/model/message.py

@@ -847,6 +847,7 @@ def __init__(
 
     def verify(self) -> None:
         if not self.is_null:
+            self._verify_parameters()
             self._verify_expression_types()
             self._verify_expressions()
             self._verify_checksums()
@@ -1229,6 +1230,27 @@ def _max_value(self, target: expr.Expr, path: Tuple[Link, ...]) -> expr.Number:
             ],
         )
 
+    def _verify_parameters(self) -> None:
+        variables = [
+            v.identifier
+            for l in self.structure
+            for e in [l.condition, l.size, l.first]
+            for v in e.findall(lambda x: isinstance(x, expr.Variable))
+            if isinstance(v, expr.Variable)
+        ]
+        for p in self.parameters:
+            if p.identifier not in variables:
+                self.error.extend(
+                    [
+                        (
+                            f'unused parameter "{p.identifier}"',
+                            Subsystem.MODEL,
+                            Severity.ERROR,
+                            p.identifier.location,
+                        )
+                    ]
+                )
+
     def _verify_expression_types(self) -> None:
         types: Dict[Field, mty.Type] = {}
 

tests/unit/model/message_test.py

@@ -709,6 +709,17 @@ def test_invalid_message_field_type() -> None:
         )
 
 
+def test_unused_parameter() -> None:
+    structure = [Link(INITIAL, Field("X")), Link(Field("X"), FINAL)]
+    types = {Field(ID("P", Location((1, 2)))): MODULAR_INTEGER, Field("X"): MODULAR_INTEGER}
+
+    assert_message_model_error(
+        structure,
+        types,
+        '^<stdin>:1:2: model: error: unused parameter "P"$',
+    )
+
+
 @pytest.mark.parametrize(
     "condition",
     [
@@ -4081,7 +4092,11 @@ def test_message_str() -> None:
         "P::M",
         [
             Link(INITIAL, Field("L")),
-            Link(Field("L"), Field("O"), condition=Greater(Variable("L"), Number(100))),
+            Link(
+                Field("L"),
+                Field("O"),
+                condition=And(Greater(Variable("L"), Number(100)), Equal(Variable("A"), TRUE)),
+            ),
             Link(Field("L"), Field("P"), condition=LessEqual(Variable("L"), Number(100))),
             Link(Field("P"), FINAL),
             Link(Field("O"), FINAL),
@@ -4102,6 +4117,7 @@ def test_message_str() -> None:
                   L : P::Modular
                      then O
                         if L > 100
+                           and A = True
                      then P
                         if L <= 100;
                   O : P::Modular

tests/unit/specification/parser_test.py

@@ -2819,7 +2819,9 @@ def test_parse_error_name_conflict_between_parameters() -> None:
            type T is mod 2 ** 8;
            type M (P : T; P : T) is
               message
-                 F : T;
+                 F : T
+                    then null
+                       if P = F;
               end message;
         end Test;
         """,