Bennett (2009) endorses the idea that it is unhelpful, and simplistic, to equate assessment for learning with formative assessment and assessment of learning with summative assessment. From a “more nuanced” view, he suggests that assessments designed primarily to serve a summative function may also function formatively, while those designed primarily to serve a formative function may also function summatively.
WILIAM, D. What is assessment for learning? Studies in Education Evaluation, v. 37, n. 1, 2011. p. 3-14 (adapted).

In a given school, each year, students of the third year of High School take a reading test which includes items taken from past Exame Nacional do Ensino Médio (ENEM) tests. These scores are not considered to their academic records. A group of English teachers meet together to review students’ performance on the test, and in particular, look at the facility (proportion correct) for different kinds of English reading items on the test. Where item facilities are lower than expected, they look at how the instruction on those which required reading skills was planned and delivered and they look at ways in which the instruction can be strengthened in the following year.
Considering the above scenario, the teacher’s decision is correctly described as assessment for learning, since