Fixed a bug that resulted in a false negative when evaluating binary operations that involve unions for either the LHS or RHS or both.

msfterictraut · msfterictraut · commit 170bfa059d53 · 2022-08-05T20:57:03.000-07:00
diff --git a/packages/pyright-internal/src/analyzer/typeUtils.ts b/packages/pyright-internal/src/analyzer/typeUtils.ts
@@ -467,7 +467,7 @@ export function mapSubtypes(type: Type, callback: (type: Type) => Type | undefin
 
 // Sorts types into a deterministic order.
 export function sortTypes(types: Type[]): Type[] {
-    return types.sort((a, b) => {
+    return types.slice(0).sort((a, b) => {
         if (a.category !== b.category) {
             return a.category - b.category;
         }
diff --git a/packages/pyright-internal/src/tests/samples/typeGuard3.py b/packages/pyright-internal/src/tests/samples/typeGuard3.py
@@ -34,9 +34,9 @@ def is_list(val: object) -> StrictTypeGuard[list[Any]]:
 
 def func3(val: dict[str, str] | list[str] | list[int] | Sequence[int]):
     if is_list(val):
-        reveal_type(val, expected_text="list[Any] | list[str] | list[int]")
+        reveal_type(val, expected_text="list[str] | list[int] | list[Any]")
     else:
-        reveal_type(val, expected_text="Sequence[int] | dict[str, str]")
+        reveal_type(val, expected_text="dict[str, str] | Sequence[int]")
 
 
 def func4(val: dict[str, str] | list[str] | list[int] | tuple[int]):
diff --git a/packages/pyright-internal/src/tests/samples/typeNarrowingTypeIs1.py b/packages/pyright-internal/src/tests/samples/typeNarrowingTypeIs1.py
@@ -46,7 +46,7 @@ def func4(a: Union[str, A]):
     if type(a) is B:
         reveal_type(a, expected_text="B")
     else:
-        reveal_type(a, expected_text="A | str")
+        reveal_type(a, expected_text="str | A")
 
 
 T = TypeVar("T")

Original file line number	Diff line number	Diff line change
`@@ -467,7 +467,7 @@ export function mapSubtypes(type: Type, callback: (type: Type) => Type \| undefin`
`467`	`467`
`468`	`468`	`// Sorts types into a deterministic order.`
`469`	`469`	`export function sortTypes(types: Type[]): Type[] {`
`470`		`- return types.sort((a, b) => {`
	`470`	`+ return types.slice(0).sort((a, b) => {`
`471`	`471`	`if (a.category !== b.category) {`
`472`	`472`	`return a.category - b.category;`
`473`	`473`	`}`