Added special-case handling of __import__ built-in call so it always returns Any type.

server/src/analyzer/expressionEvaluator.ts

@@ -1907,6 +1907,13 @@ export class ExpressionEvaluator {
             } else {
                 type = this._validateCallArguments(errorNode, argList, callType,
                     new TypeVarMap(), specializeReturnType);
+
+                if (FunctionType.getBuiltInName(callType) === '__import__') {
+                    // For the special __import__ type, we'll override the return type to be "Any".
+                    // This is required because we don't know what module was imported, and we don't
+                    // want to fail type checks when accessing members of the resulting module type.
+                    type = AnyType.create();
+                }
             }
 
             if (!type) {

server/src/analyzer/sourceFile.ts

@@ -166,6 +166,7 @@ export class SourceFile {
         this._isBuiltInStubFile = false;
         if (this._isStubFile) {
             if (this._filePath.endsWith(normalizeSlashes('/collections/__init__.pyi')) ||
+                    fileName === 'builtins.pyi' ||
                     fileName === '_importlib_modulespec.pyi' ||
                     fileName === 'dataclasses.pyi' ||
                     fileName === 'abc.pyi' ||

server/src/tests/samples/import1.py

@@ -0,0 +1,6 @@
+# This sample tests the type analyzer's handling of the built-in
+# __import__ function.
+
+# This should not generate a type error.
+__path__ = __import__('pkgutil').extend_path(__path__, __name__)
+

server/src/tests/typeAnalyzer.test.ts

@@ -741,3 +741,8 @@ test('AssignmentExpr3', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['assignmentExpr3.py']);
     validateResults(analysisResults, 3);
 });
+
+test('Import1', () => {
+    const analysisResults = TestUtils.typeAnalyzeSampleFiles(['import1.py']);
+    validateResults(analysisResults, 0);
+});