Fixed a bug that resulted in a false negative when a Literal with multiple arguments is used in a value expression. It should be treated as a UnionType special form in this case. This addresses #7870.

erictraut · erictraut · commit ecdea2caade5 · 2024-05-07T21:02:47.000-07:00
diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -14897,7 +14897,13 @@ export function createTypeEvaluator(
             literalTypes.push(type);
         }
 
-        return combineTypes(literalTypes);
+        let result = combineTypes(literalTypes);
+
+        if (isUnion(result) && unionClassType && isInstantiableClass(unionClassType)) {
+            result = TypeBase.cloneAsSpecialForm(result, ClassType.cloneAsInstance(unionClassType));
+        }
+
+        return result;
     }
 
     // Creates a ClassVar type.

Original file line number	Diff line number	Diff line change
`@@ -14897,7 +14897,13 @@ export function createTypeEvaluator(`
`14897`	`14897`	`literalTypes.push(type);`
`14898`	`14898`	`}`
`14899`	`14899`
`14900`		`- return combineTypes(literalTypes);`
	`14900`	`+ let result = combineTypes(literalTypes);`
	`14901`	`+`
	`14902`	`+ if (isUnion(result) && unionClassType && isInstantiableClass(unionClassType)) {`
	`14903`	`+ result = TypeBase.cloneAsSpecialForm(result, ClassType.cloneAsInstance(unionClassType));`
	`14904`	`+ }`
	`14905`	`+`
	`14906`	`+ return result;`
`14901`	`14907`	`}`
`14902`	`14908`
`14903`	`14909`	`// Creates a ClassVar type.`