Fixed type narrowing bug that affected the A is B type narrowing pa…

…ttern when `A` has the type `type`. This addresses #5714.
microsoft · Aug 15, 2023 · 97e432a · 97e432a
1 parent 682961d
commit 97e432a
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diff --git a/packages/pyright-internal/src/analyzer/typeGuards.ts b/packages/pyright-internal/src/analyzer/typeGuards.ts
@@ -2105,6 +2105,10 @@ function narrowTypeForClassComparison(
             }
 
             if (isClassInstance(concreteSubtype) && TypeBase.isInstance(subtype)) {
+                if (ClassType.isBuiltIn(concreteSubtype, 'type')) {
+                    return classType;
+                }
+
                 return undefined;
             }
 

diff --git a/packages/pyright-internal/src/tests/samples/typeNarrowingIsClass1.py b/packages/pyright-internal/src/tests/samples/typeNarrowingIsClass1.py
@@ -56,3 +56,10 @@ def func5(x: type[A] | type[B] | type[T]) -> type[A] | type[B] | type[T]:
         reveal_type(x, expected_text="type[B] | type[T@func5]")
 
     return x
+
+
+def func6(x: type):
+    if x is str:
+        reveal_type(x, expected_text="type[str]")
+    else:
+        reveal_type(x, expected_text="type")