fix: throw error when alias method is used on inkoved solids (#2672)

fix #2670

python_modules/dagster/dagster/core/definitions/composition.py

@@ -334,6 +334,19 @@ def __getitem__(self, idx):
             )
         )
 
+    def alias(self, _):
+        raise DagsterInvariantViolationError(
+            'In {source} {name}, attempted to call alias method for {cls}. This object '
+            'represents the output "{out}" from the already invoked solid "{solid}". Consider '
+            'checking the location of parentheses.'.format(
+                source=current_context().source,
+                name=current_context().name,
+                cls=self.__class__.__name__,
+                solid=self.solid_name,
+                out=self.output_name,
+            )
+        )
+
 
 class InputMappingNode(object):
     def __init__(self, input_def):

python_modules/dagster/dagster_tests/core_tests/definitions_tests/test_composition.py

@@ -620,3 +620,15 @@ def uninvoked_aliased_solid_pipeline():
             add_one(return_one.alias('something'))
 
         execute_pipeline(uninvoked_aliased_solid_pipeline)
+
+
+def test_alias_on_invoked_solid_fails():
+    with pytest.raises(
+        DagsterInvariantViolationError, match=r'.*Consider checking the location of parentheses.'
+    ):
+
+        @pipeline
+        def alias_on_invoked_solid_pipeline():
+            return_one().alias('something')
+
+        execute_pipeline(alias_on_invoked_solid_pipeline)