unexpected compiler error

Can someone help me to debug this compile error please?

It doesn't reference a code module, and I don't know what "Build line 43305" refers to.

when I "Clean" the project, it fails with:

BUILD: ERROR: /Users/alansmith/Documents/watchApp/raceQs/source/perfectStart.mc:252:  Duplicate declaration of symbol 'onUpdate' in class 'PerfectStart'.

I have two onUpdate functions, differentiated by qualifiers which have been there for many moons without complaint.

(:rectangle)
	function onUpdate(dc) {
....

(:rectangle)
	function onUpdate(dc) {

running SDK 3.1.9