More fixup.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

@@ -640,9 +640,10 @@ module LocalFlow {
       )
       or
       // Needed for read steps for pattern matching involving properties.
+      // TODO: Can be written in a more nice way.
       scope = def.getExpr() and
       e.(VariablePatternExpr).getVariableDeclExpr() =
-        def.(AssignableDefinitions::PatternDefinition).getExpr() and
+        def.(AssignableDefinitions::PatternDefinition).getDeclaration() and
       exactScope = false and
       isSuccessor = false and
       not def.(AssignableDefinitions::PatternDefinition).isTopLevel()
@@ -906,18 +907,30 @@ private predicate fieldOrPropertyStore(Expr e, ContentSet c, Expr src, Expr q, b
   )
 }
 
-private predicate patternPropertyRead(Expr e1, ContentSet c, VariablePatternExpr e2) {
-  exists(IsExpr ie, RecursivePatternExpr p, TypeAccess ta, Property prop |
-    e1 = ie.getExpr() and
-    p = ie.getPattern() and
-    ta = p.getTypeAccess() and
-    e2 = p.getPropertyPatterns().getPattern(_) and
+private predicate patternPropertyRead0(RecursivePatternExpr rpe, ContentSet c, VariablePatternExpr e) {
+  exists(TypeAccess ta, Property prop |
+    ta = rpe.getTypeAccess() and
+    e = rpe.getPropertyPatterns().getPattern(_) and
     prop.getDeclaringType() = ta.getType() and
-    prop.getName() = e2.(LabeledPatternExpr).getLabel() and
+    prop.getName() = e.(LabeledPatternExpr).getLabel() and
     c.isProperty(prop)
   )
 }
 
+private predicate patternPropertyRead(Expr e1, ContentSet c, VariablePatternExpr e2) {
+  exists(IsExpr ie, RecursivePatternExpr rpe |
+    e1 = ie.getExpr() and
+    rpe = ie.getPattern() and
+    patternPropertyRead0(rpe, c, e2)
+  )
+  or
+  exists(Switch sw, RecursivePatternExpr rpe |
+    e1 = sw.getExpr() and
+    rpe = sw.getACase().getPattern() and
+    patternPropertyRead0(rpe, c, e2)
+  )
+}
+
 /**
  * Holds if `e2` is an expression that reads field or property `c` from
  * expression `e1`.