remove local modifier validation during parse

add parameter modifier checking to validation

langserver/java/validation/modifier-errors.js

@@ -1,4 +1,4 @@
-const { SourceType, SourceMethod, SourceField, SourceConstructor, SourceInitialiser } = require('../source-type');
+const { SourceType, SourceMethod, SourceParameter, SourceField, SourceConstructor, SourceInitialiser } = require('../source-type');
 const { Token } = require('../tokenizer');
 const ParseProblem = require('../parsetypes/parse-problem');
 
@@ -68,6 +68,25 @@ function checkFieldModifiers(field, probs) {
     }
 }
 
+/**
+ * @param {SourceParameter} param
+ * @param {ParseProblem[]} probs 
+ */
+function checkParameterModifiers(param, probs) {
+    // the only permitted modifier is final
+    let has_final = false;
+    param.modifierTokens.forEach(mod => {
+        if (mod.value === 'final') {
+            if (has_final) {
+                probs.push(ParseProblem.Error(mod, `Repeated modifier: final`));
+            }
+            has_final = true;
+            return;
+        }
+        probs.push(ParseProblem.Error(mod, `Parameter declarations cannot be ${mod.value}`));
+    });
+}
+
 /**
  * @param {SourceType} type
  * @param {Map<string,*>} ownertypemods
@@ -78,6 +97,8 @@ function checkMethodModifiers(type, ownertypemods, method, probs) {
     checkDuplicate(method.modifierTokens, probs);
     checkConflictingAccess(method.modifierTokens, probs);
 
+    method.parameters.forEach(p => checkParameterModifiers(p, probs));
+
     const allmods = new Map(method.modifierTokens.map(m => [m.source, m]));
     const is_interface_kind = /@?interface/.test(type.typeKind);
     const has_body = method.hasImplementation;