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[flang] Format label scope is independent of block scope

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Compilation of the following program currently generates a warning message:

        i = 1
        if (i .eq. 0) then
          write(6, 200) i
200       format (I8)
        end if
        write(6, 200) i
      end

x.f90:6:9: Label '200' is not in scope
          write(6, 200) i
          ^^^^^^^^^^^^^^^

Whereas branch targets must conform to the Clause 11.1.2.1 program
requirement "Transfer of control to the interior of a block from
outside the block is prohibited, ...", this doesn't apply to format
statement references.
This commit is contained in:
peter klausler 2020-08-31 10:45:37 -07:00
parent 8931add617
commit 646f19bb9d
2 changed files with 11 additions and 0 deletions
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6
flang/lib/Semantics/resolve-labels.cpp
View file

@ -935,6 +935,12 @@ void CheckScopeConstraints(const SourceStmtList &stmts,
parser::MessageFormattedText{
"Label '%u' was not found"_err_en_US, SayLabel(label)});
} else if (!InInclusiveScope(scopes, scope, target.proxyForScope)) {
// Clause 11.1.2.1 prohibits transfer of control to the interior of a
// block from outside the block, but this does not apply to formats.
if (target.labeledStmtClassificationSet.test(
TargetStatementEnum::Format)) {
continue;
}
context.Say(position,
parser::MessageFormattedText{
"Label '%u' is not in scope"_en_US, SayLabel(label)});

5
flang/test/Semantics/io07.f90
View file

@ -17,6 +17,11 @@
2011 format(:2L2)
2012 format(2L2 : 2L2)
write(*,2013) 'Hello'
if (2+2.eq.4) then
2013 format(A10) ! ok to reference outside the if block
endif
! C1302 warnings; no errors
2051 format(1X3/)
2052 format(1X003/)