[flang-commits] [PATCH] D134391: [flang][NFC] Document ambiguous case of DATA in BLOCK

[Peter Klausler via Phabricator via flang-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG81d857d037b5: [flang][NFC] Document ambiguous case of DATA in BLOCK (authored by klausler).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134391/new/

https://reviews.llvm.org/D134391

Files:
  flang/docs/Extensions.md


Index: flang/docs/Extensions.md
===================================================================
--- flang/docs/Extensions.md
+++ flang/docs/Extensions.md
@@ -415,3 +415,25 @@
   to some forms of input in this situation.)
   For sequential formatted output, RECL= serves as a limit on record lengths
   that raises an error when it is exceeded.
+
+* When a `DATA` statement in a `BLOCK` construct could be construed as
+  either initializing a host-associated object or declaring a new local
+  initialized object, f18 interprets the standard's classification of
+  a `DATA` statement as being a "declaration" rather than a "specification"
+  construct, and notes that the `BLOCK` construct is defined as localizing
+  names that have specifications in the `BLOCK` construct.
+  So this example will elicit an error about multiple initialization:
+```
+subroutine subr
+  integer n = 1
+  block
+    data n/2/
+  end block
+end subroutine
+```
+
+  Other Fortran compilers disagree with each other in their interpretations
+  of this example.
+  The precedent among the most commonly used compilers
+  agrees with f18's interpretation: a `DATA` statement without any other
+  specification of the name refers to the host-associated object.


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