Fixed bug that results in a false positive when using a traditional (…

…non-PEP 695) TypeVar in a type expression and assigning to a `TypeForm`. This addresses microsoft#9159. (microsoft#9160)
qmi03 · Oct 6, 2024 · 649a2ab · 649a2ab
1 parent f55ee0f
commit 649a2ab
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Showing 6 changed files with 35 additions and 14 deletions.
diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -4684,6 +4684,10 @@ export function createTypeEvaluator(
                 type = validateSymbolIsTypeExpression(node, type, !!effectiveTypeInfo.includesVariableDecl);
             }
 
+            if (isTypeVar(type) && !type.shared.isSynthesized) {
+                type = validateTypeVarUsage(node, type, flags);
+            }
+
             // Add TypeForm details if appropriate.
             type = addTypeFormForSymbol(node, type, flags, !!effectiveTypeInfo.includesVariableDecl);
         } else {
@@ -4701,7 +4705,7 @@ export function createTypeEvaluator(
             }
         }
 
-        if (isParamSpec(type)) {
+        if (isParamSpec(type) && type.priv.scopeId) {
             if (flags & EvalFlags.NoParamSpec) {
                 addDiagnostic(DiagnosticRule.reportInvalidTypeForm, LocMessage.paramSpecContext(), node);
                 type = UnknownType.create();
@@ -4722,10 +4726,6 @@ export function createTypeEvaluator(
             }
         }
 
-        if (isTypeVar(type) && !type.shared.isSynthesized) {
-            type = validateTypeVarUsage(node, type, flags);
-        }
-
         return { type, isIncomplete };
     }
 
@@ -4788,7 +4788,7 @@ export function createTypeEvaluator(
             return true;
         }
 
-        if (isTypeVar(type) && !type.priv.scopeId) {
+        if (isTypeVar(type)) {
             return true;
         }
 
@@ -5123,7 +5123,7 @@ export function createTypeEvaluator(
                 return type;
             }
 
-            if (!type.shared.isSynthesized) {
+            if (!type.shared.isSynthesized && (flags & EvalFlags.InstantiableType) !== 0) {
                 const message = isParamSpec(type)
                     ? LocMessage.paramSpecNotUsedByOuterScope()
                     : LocMessage.typeVarNotUsedByOuterScope();

diff --git a/packages/pyright-internal/src/tests/samples/literals6.py b/packages/pyright-internal/src/tests/samples/literals6.py
@@ -28,8 +28,7 @@
 Wrong11 = Literal[...]
 
 
-def func():
-    ...
+def func(): ...
 
 
 Wrong12 = Literal[func]
@@ -59,7 +58,7 @@ def func():
 # This should generate two errors.
 var7: Literal[Path("abcd")]
 
-# This should generate two errors.
+# This should generate an error.
 var8: Literal[T]
 
 # This should generate an error.

diff --git a/packages/pyright-internal/src/tests/samples/paramSpec12.py b/packages/pyright-internal/src/tests/samples/paramSpec12.py
@@ -67,7 +67,7 @@ def union_args1(
     ) -> None:
         pass
 
-    # This should generate an error because P.args cannot be used in
+    # This should generate two errors because P.args cannot be used in
     # a union.
     def union_args2(
         *args: P.args | Sequence[Any], **kwargs: Union[P.kwargs, Mapping[str, Any]]

diff --git a/packages/pyright-internal/src/tests/samples/typeForm2.py b/packages/pyright-internal/src/tests/samples/typeForm2.py
@@ -19,12 +19,15 @@
     Type,
     TypeAlias,
     TypeGuard,
+    TypeVar,
     Union,
     Unpack,
 )
 import typing as tp
 from typing_extensions import TypeForm, TypeIs, ReadOnly
 
+T = TypeVar("T")
+
 type TA1 = int | str
 type TA2[T] = list[T] | T
 TA3: TypeAlias = Annotated[int, "meta"]
@@ -187,7 +190,26 @@ def func5():
     reveal_type(t2, expected_text="TypeForm[TypeForm[TypeForm[int | str]]]")
 
 
-def func6():
+def func6(x: T) -> T:
+    v1: TypeForm[T] = T
+    v2 = tf(T)
+    reveal_type(v2, expected_text="TypeForm[T@func6]")
+
+    v3: TypeForm[T | int] = T
+    v3 = T | int
+
+    v4 = tf(T | int)
+    reveal_type(v4, expected_text="TypeForm[T@func6 | int]")
+
+    v5: TypeForm[list[T]] = list[T]
+
+    v6 = tf(list[T])
+    reveal_type(v6, expected_text="TypeForm[list[T@func6]]")
+
+    return x
+
+
+def func7():
     # This should generate an error.
     t1 = tf(Generic)
 

diff --git a/packages/pyright-internal/src/tests/typeEvaluator3.test.ts b/packages/pyright-internal/src/tests/typeEvaluator3.test.ts
@@ -596,7 +596,7 @@ test('Literals5', () => {
 test('Literals6', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['literals6.py']);
 
-    TestUtils.validateResults(analysisResults, 26);
+    TestUtils.validateResults(analysisResults, 25);
 });
 
 test('Literals7', () => {

diff --git a/packages/pyright-internal/src/tests/typeEvaluator4.test.ts b/packages/pyright-internal/src/tests/typeEvaluator4.test.ts
@@ -621,7 +621,7 @@ test('ParamSpec11', () => {
 
 test('ParamSpec12', () => {
     const results = TestUtils.typeAnalyzeSampleFiles(['paramSpec12.py']);
-    TestUtils.validateResults(results, 15);
+    TestUtils.validateResults(results, 14);
 });
 
 test('ParamSpec13', () => {