tree 2119eb8bd46f2e4854743d2d9f3af5bb7aa60dca
parent 4176f93d42bae47ad133769c27658e1e917d85b5
author peter klausler <pklausler@nvidia.com> 1634232779 -0700
committer Copybara-Service <copybara-worker@google.com> 1634253934 -0700

[flang] Admit NULL() in generic procedure resolution cases

Semantics is rejecting valid programs with NULL() actual arguments
to generic interfaces, including user-defined operators.  Subclause
16.9.144(para 6) makes clear that NULL() can be a valid actual
argument to a generic interface so long as it does not produce
ambiguity.  This patch handles those cases, revises existing
tests, and adjust an error message about NULL() operands to
appear less like a blanket prohibition.

Differential Revision: https://reviews.llvm.org/D111850

GitOrigin-RevId: 0fcda9ae5757dc48f3b7ee668e4a59c5749447e7