C#: The field access should be on this for it to be compatible with readonly.

michaelnebel · michaelnebel · commit 19e9197874cd · 2025-05-21T15:19:26.000+02:00
diff --git a/csharp/ql/src/Language Abuse/MissedReadonlyOpportunity.ql b/csharp/ql/src/Language Abuse/MissedReadonlyOpportunity.ql
@@ -20,7 +20,10 @@ predicate defTargetsField(AssignableDefinition def, Field f) {
 predicate isReadonlyCompatibleDefinition(AssignableDefinition def, Field f) {
   defTargetsField(def, f) and
   (
-    def.getEnclosingCallable().(Constructor).getDeclaringType() = f.getDeclaringType()
+    def.getEnclosingCallable().(StaticConstructor).getDeclaringType() = f.getDeclaringType()
+    or
+    def.getEnclosingCallable().(InstanceConstructor).getDeclaringType() = f.getDeclaringType() and
+    def.getTargetAccess().(QualifiableExpr).getQualifier() instanceof ThisAccess
     or
     def instanceof AssignableDefinitions::InitializerDefinition
   )

Original file line number	Diff line number	Diff line change
`@@ -20,7 +20,10 @@ predicate defTargetsField(AssignableDefinition def, Field f) {`
`20`	`20`	`predicate isReadonlyCompatibleDefinition(AssignableDefinition def, Field f) {`
`21`	`21`	`defTargetsField(def, f) and`
`22`	`22`	`(`
`23`		`- def.getEnclosingCallable().(Constructor).getDeclaringType() = f.getDeclaringType()`
	`23`	`+ def.getEnclosingCallable().(StaticConstructor).getDeclaringType() = f.getDeclaringType()`
	`24`	`+ or`
	`25`	`+ def.getEnclosingCallable().(InstanceConstructor).getDeclaringType() = f.getDeclaringType() and`
	`26`	`+ def.getTargetAccess().(QualifiableExpr).getQualifier() instanceof ThisAccess`
`24`	`27`	`or`
`25`	`28`	`def instanceof AssignableDefinitions::InitializerDefinition`
`26`	`29`	`)`