From 54228277a5e9eee6de0d5429e7fe204d66b04c0e Mon Sep 17 00:00:00 2001
From: Eric Traut <erictr@microsoft.com>
Date: Wed, 13 Oct 2021 14:39:52 -0700
Subject: [PATCH] Added support for an unpacked tuple assignment within an
 instance method when the source of the assignment is the `self` parameter.

---
 .../src/analyzer/typeEvaluator.ts                 |  2 ++
 .../src/tests/samples/namedTuples5.py             | 15 +++++++++++++++
 .../src/tests/typeEvaluator1.test.ts              |  6 ++++++
 3 files changed, 23 insertions(+)
 create mode 100644 packages/pyright-internal/src/tests/samples/namedTuples5.py

diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
index a3428ac9789f..dc56f88ce227 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluator.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -2494,6 +2494,8 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
         // entries at that location.
         const unpackIndex = target.expressions.findIndex((expr) => expr.nodeType === ParseNodeType.Unpack);
 
+        type = makeTopLevelTypeVarsConcrete(type);
+
         doForEachSubtype(type, (subtype) => {
             // Is this subtype a tuple?
             const tupleType = getSpecializedTupleType(subtype);
diff --git a/packages/pyright-internal/src/tests/samples/namedTuples5.py b/packages/pyright-internal/src/tests/samples/namedTuples5.py
new file mode 100644
index 000000000000..334a4d06d4ab
--- /dev/null
+++ b/packages/pyright-internal/src/tests/samples/namedTuples5.py
@@ -0,0 +1,15 @@
+# This sample tests the case where a NamedTuple object is referenced
+# through a `self` parameter.
+
+from typing import Literal, NamedTuple
+
+
+class Fruit(NamedTuple):
+    name: str
+    cost: float
+
+    def new_cost(self, new_cost: float):
+        my_name, my_cost = self
+        t1: Literal["str"] = reveal_type(my_name)
+        t2: Literal["float"] = reveal_type(my_cost)
+        return Fruit(my_name, new_cost)
diff --git a/packages/pyright-internal/src/tests/typeEvaluator1.test.ts b/packages/pyright-internal/src/tests/typeEvaluator1.test.ts
index f8149488ec45..f23a73ff4dc9 100644
--- a/packages/pyright-internal/src/tests/typeEvaluator1.test.ts
+++ b/packages/pyright-internal/src/tests/typeEvaluator1.test.ts
@@ -1013,6 +1013,12 @@ test('NamedTuples4', () => {
     TestUtils.validateResults(analysisResults, 0);
 });
 
+test('NamedTuples5', () => {
+    const analysisResults = TestUtils.typeAnalyzeSampleFiles(['namedTuples5.py']);
+
+    TestUtils.validateResults(analysisResults, 0);
+});
+
 test('Slots1', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['slots1.py']);