Merge pull request #17340 from hvitved/csharp/ssa-exclude-enums

Author: hvitved

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

@@ -108,7 +108,11 @@ private module SourceVariableImpl {
    */
   predicate isPlainFieldOrPropAccess(FieldOrPropAccess fpa, FieldOrProp fp, Callable c) {
     fieldOrPropAccessInCallable(fpa, fp, c) and
-    (ownFieldOrPropAccess(fpa) or fp.isStatic())
+    (
+      ownFieldOrPropAccess(fpa)
+      or
+      fp.isStatic() and not fp instanceof EnumConstant
+    )
   }
 
   /**

csharp/ql/test/library-tests/dataflow/ssa/Enum.cs

@@ -0,0 +1,14 @@
+enum E
+{
+    A
+}
+
+class EnumTest
+{
+    void M()
+    {
+        // enums are modelled as fields; this test checks that we do not compute SSA for them
+        var e1 = E.A;
+        var e2 = E.A;
+    }
+}