Fixed a bug that resulted in spurious type evaluation errors when dealing with classes that have synthesized symbols such as dataclasses, namedtuples and TypedDicts. This addresses microsoft/pylance-release#4151.

Author: msfterictraut

packages/pyright-internal/src/analyzer/typeEvaluator.ts

@@ -16389,7 +16389,9 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
 
         // The scope for this class becomes the "fields" for the corresponding type.
         const innerScope = ScopeUtils.getScopeForNode(node.suite);
-        classType.details.fields = innerScope?.symbolTable || new Map<string, Symbol>();
+        classType.details.fields = innerScope?.symbolTable
+            ? new Map<string, Symbol>(innerScope.symbolTable)
+            : new Map<string, Symbol>();
 
         // Determine whether the class's instance variables are constrained
         // to those defined by __slots__. We need to do this prior to dataclass