scala/scala — pull request #2420 by retronym (2013-04-20 10:09:29+00:00)
Title: SI-6675 Avoid spurious warning about pattern bind arity.

In 692372ce, we added a warning (under -Xlint) when binding
a `TupleN` in to a single pattern binder, which wasn't allowed
before 2.10.0, and more often than not represents a bug.

However, that warning overstretched, and warned even when
using a Tuple Pattern to bind to the elements of such a value.

This commit checks for this case, and avoids the spurious warnings.

A new test case is added for this case to go with the existing
test for SI-6675:

$ ./tools/partest-ack 6675
% tests-with-matching-paths ... 3
% tests-with-matching-code ... 2
# 3 tests to run.
test/partest --show-diff --show-log \
test/files/neg/t6675-old-patmat.scala \
test/files/neg/t6675.scala \
test/files/pos/t6675.scala \
""

Testing individual files
testing: [...]/files/pos/t6675.scala [ OK ]

Testing individual files
testing: [...]/files/neg/t6675-old-patmat.scala [ OK ]
testing: [...]/files/neg/t6675.scala [ OK ]
All of 3 tests were successful (elapsed time: 00:00:03)

Review by @adriaanm. This change **does not close the ticket**, it just refines the warning.