Move enum number analysis to sementic2

Author: abulgit

compiler/src/dmd/enumsem.d

@@ -345,6 +345,10 @@ void enumSemantic(Scope* sc, EnumDeclaration ed)
 
     //if (ed.defaultval) printf("ed.defaultval: %s %s\n", ed.defaultval.toChars(), ed.defaultval.type.toChars());
     //printf("members = %s\n", members.toChars());
+    
+    // Set semantic2done here to indicate all members have been processed
+    // This prevents using the enum in a final switch while being defined
+    ed.semanticRun = PASS.semantic2done;
 }
 
 Expression getDefaultValue(EnumDeclaration ed, Loc loc)
@@ -734,7 +738,7 @@ void enumSemantic2(Scope* sc, EnumDeclaration ed)
         return;
     }
 
-    assert(ed.semanticRun == PASS.semanticdone);
+    assert(ed.semanticRun == PASS.semanticdone || ed.semanticRun == PASS.semantic2);
     ed.semanticRun = PASS.semantic2;
 
     if (!ed.members || !ed.symtab || ed.errors)