1 files changed, 31 insertions, 2 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
index c49718ab..7046d4c6 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
@@ -49,8 +49,9 @@ public class ProblemValidator extends AbstractProblemValidator {
         public static final String INVALID_SUPERTYPE_ISSUE = ISSUE_PREFIX + "INVALID_SUPERTYPE";
         public static final String INVALID_REFERENCE_TYPE_ISSUE = ISSUE_PREFIX + "INVALID_REFERENCE_TYPE";
         public static final String INVALID_ARITY_ISSUE = ISSUE_PREFIX + "INVALID_ARITY";
+        public static final String INVALID_MODALITY_ISSUE = ISSUE_PREFIX + "INVALID_MODALITY";
+        public static final String INVALID_RULE_ISSUE = ISSUE_PREFIX + "INVALID_RULE";
         public static final String INVALID_TRANSITIVE_CLOSURE_ISSUE = ISSUE_PREFIX + "INVALID_TRANSITIVE_CLOSURE";
-        public static final String INVALID_VALUE_ISSUE = ISSUE_PREFIX + "INVALID_VALUE";
         public static final String UNSUPPORTED_ASSERTION_ISSUE = ISSUE_PREFIX + "UNSUPPORTED_ASSERTION";
         public static final String UNKNOWN_EXPRESSION_ISSUE = ISSUE_PREFIX + "UNKNOWN_EXPRESSION";
         public static final String INVALID_ASSIGNMENT_ISSUE = ISSUE_PREFIX + "INVALID_ASSIGNMENT";
@@ -336,8 +337,24 @@ public class ProblemValidator extends AbstractProblemValidator {
         }
 
         @Check
-        public void checkParameterType(Parameter parameter) {
+        public void checkParameter(Parameter parameter) {
                 checkArity(parameter, ProblemPackage.Literals.PARAMETER__PARAMETER_TYPE, 1);
+                var parametricDefinition = EcoreUtil2.getContainerOfType(parameter, ParametricDefinition.class);
+                if (parametricDefinition instanceof RuleDefinition) {
+                        if (parameter.getParameterType() != null && parameter.getModality() == Modality.NONE) {
+                                acceptError("Parameter type modality must be specified.", parameter,
+                                                ProblemPackage.Literals.PARAMETER__PARAMETER_TYPE, 0, INVALID_MODALITY_ISSUE);
+                        }
+                } else {
+                        if (parameter.getConcreteness() != Concreteness.PARTIAL || parameter.getModality() != Modality.NONE) {
+                                acceptError("Modal parameter types are only supported in rule definitions.", parameter, null, 0,
+                                                INVALID_MODALITY_ISSUE);
+                        }
+                        if (parameter.getBinding() != ParameterBinding.SINGLE) {
+                                acceptError("Parameter binding annotations are only supported in rule definitions.", parameter,
+                                                ProblemPackage.PARAMETER__BINDING, 0, INVALID_MODALITY_ISSUE);
+                        }
+                }
         }
 
         @Check
@@ -353,6 +370,18 @@ public class ProblemValidator extends AbstractProblemValidator {
         }
 
         @Check
+        public void checkRuleDefinition(RuleDefinition ruleDefinition) {
+                if (ruleDefinition.getKind() != RuleKind.REFINEMENT && ruleDefinition.getPreconditions().isEmpty()) {
+                        acceptError("Decision and propagation rules must have at least one precondition.", ruleDefinition,
+                                        ProblemPackage.Literals.NAMED_ELEMENT__NAME, 0, INVALID_RULE_ISSUE);
+                }
+                if (ruleDefinition.getConsequents().size() != 1) {
+                        acceptError("Rules must have exactly one consequent.", ruleDefinition,
+                                        ProblemPackage.Literals.NAMED_ELEMENT__NAME, 0, INVALID_RULE_ISSUE);
+                }
+        }
+
+        @Check
         public void checkAssertion(Assertion assertion) {
                 var relation = assertion.getRelation();
                 if (relation instanceof DatatypeDeclaration) {