Add regression tests

Author: ahejlsberg

tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts

@@ -175,3 +175,19 @@ class TableBaseEnum<
         iSpec[null! as keyof PublicSpec];
     }
 }
+
+// Repros from #45145
+
+function f10<T extends { a: string } | undefined>(x: T, y: Partial<T>) {
+    y = x;
+}
+
+type SqlInsertSet<T> = T extends undefined ? object : { [P in keyof T]: unknown };
+
+class SqlTable<T> {
+    protected validateRow(_row: Partial<SqlInsertSet<T>>): void {
+    }
+    public insertRow(row: SqlInsertSet<T>) {
+        this.validateRow(row);
+    }
+}