Hanafi
The sources give no view for it here.
نذر صوم يوم يوافق الجمعة
هل يلزم من نذر صوم يوم فوافق يوم جمعة الوفاء بنذره؟
Each school’s answer
Hanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
٧٩٦ - مَسْأَلَةٌ: فَلَوْ نَذَرَ الْمَرْءُ صَوْمَ يَوْمَ يُفِيقُ، أَوْ ذَلِكَ فَوَافَقَ يَوْمَ جُمُعَةٍ لَمْ يَلْزَمْ؛ لِأَنَّهُ لَا يَصُومُ يَوْمًا قَبْلَهُ، وَلَا يَوْمًا بَعْدَهُ، وَلَا وَافَقَ صَوْمًا كَانَ يَصُومُهُ، وَلَا يَجُوزُ صِيَامُهُ إلَّا بِأَحَدِ هَذَيْنِ الْوَجْهَيْنِ كَمَا ذَكَرْنَا قَبْلُ وَبِاَللَّهِ تَعَالَى التَّوْفِيقُ. [مَسْأَلَةٌ صَوْمُ اللَّيْلِ]
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What bears this mark is in our words, our standard wording; the books’ texts stay as they are.