How to debug when UBT breaks with literally 2000 engine file errors.

By working through each line in the 6 files I edited today commenting them in/out one at a time I’ve determined the following to cause the issue.

WTF.h

UFUNCTION(BlueprintCallable, Category = "Appearance")
void SetColorAndOpacity(FSlateColor InColorAndOpacity);

WTF.cpp

void UEnhancedRichText::SetColorAndOpacity(FSlateColor InColorAndOpacity) {

}

If i paste that into notepad++ there aren’t any non-renderable characters i can see.