UMLR — UML 2.6 Issue --- SignalEvent Triggers

On p 345 under the details of Transition it says:

SignalEvent triggers and CallEvent triggers are not distinguishable by syntax and must be discriminated by their declaration elsewhere.

However, on the next page under Signal receipt signal it says:

The Signal receipt symbol is shown as a five-pointed polygon that looks like a rectangle with a triangular notch in one of its sides (either one). It maps to the trigger of the Transition and does not map to an Action of the Activity that specifies the effect Behavior. The names of the Signals of the Trigger as well as any guard are contained within the symbol as follows:

<trigger> [‘,’ <trigger>]* [‘[‘ <guard> ‘]’]

Where <trigger> is specified as described in sub clause 13.3.4 with the restriction that only Signal and change Event types are allowed. The trigger symbol is always first in the path of symbols and a compound transition can only have at most one such symbol.

This means, that when the Signal Receipt symbol is used, and the trigger syntax is <name>[‘(‘[<assignment-specification>]’])’] is unambiguously a SignalEvent trigger and not a CallEvent trigger