[flang] Check definability for logical INQUIRE specifiers

[klausler]

check-io.cpp was missing checks for the definability of logical-valued specifiers in INQUIRE statements (e.g. EXIST=), and therefore also not noting the definitions of those variables. This could lead to bogus warnings about undefined function result variables, and also to missed errors about immutable objects appearing in those specifiers.

Fixes #144453.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Peter Klausler (klausler)

Changes

check-io.cpp was missing checks for the definability of logical-valued specifiers in INQUIRE statements (e.g. EXIST=), and therefore also not noting the definitions of those variables. This could lead to bogus warnings about undefined function result variables, and also to missed errors about immutable objects appearing in those specifiers.

Fixes #144453.

---

Full diff: https://github.com/llvm/llvm-project/pull/144797.diff

2 Files Affected:

• (modified) flang/lib/Semantics/check-io.cpp (+2)
• (added) flang/test/Semantics/bug144453.f90 (+10)

diff --git a/flang/lib/Semantics/check-io.cpp b/flang/lib/Semantics/check-io.cpp
index 10b32d9af0f88..a1ff4b922268b 100644
--- a/flang/lib/Semantics/check-io.cpp
+++ b/flang/lib/Semantics/check-io.cpp
@@ -478,6 +478,8 @@ void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
     specKind = IoSpecKind::Pending;
     break;
   }
+  CheckForDefinableVariable(std::get<parser::ScalarLogicalVariable>(spec.t),
+      parser::ToUpperCaseLetters(common::EnumToString(specKind)));
   SetSpecifier(specKind);
 }
 
diff --git a/flang/test/Semantics/bug144453.f90 b/flang/test/Semantics/bug144453.f90
new file mode 100644
index 0000000000000..85c0892bffb5c
--- /dev/null
+++ b/flang/test/Semantics/bug144453.f90
@@ -0,0 +1,10 @@
+!RUN: %python %S/test_errors.py %s %flang_fc1
+function func(immutable)
+  logical func
+  logical, intent(in) :: immutable
+  !No warning about an undefined function result should appear
+  INQUIRE(file="/usr/local/games/adventure", EXIST=func)
+  !ERROR: EXIST variable 'immutable' is not definable
+  !BECAUSE: 'immutable' is an INTENT(IN) dummy argument
+  INQUIRE(file="/usr/local/games/adventure", EXIST=immutable)
+end