[flang-commits] [flang] [flang] Catch bad usage case of whole assumed-size array (PR #132052)

[Peter Klausler via flang-commits]

https://github.com/klausler created https://github.com/llvm/llvm-project/pull/132052

Whole assumed-size arrays are generally not allowed outside specific contexts, where expression analysis notes that they can appear.  But contexts can nest, and in the case of an actual argument that turns out to be an array constructor, the permission to use a whole assumed-size array must be rescinded.

Fixes https://github.com/llvm/llvm-project/issues/131909.

>From c40d4133702b3d9fc56be26a2d0b48f36d618f94 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Wed, 19 Mar 2025 09:03:05 -0700
Subject: [PATCH] [flang] Catch bad usage case of whole assumed-size array

Whole assumed-size arrays are generally not allowed outside
specific contexts, where expression analysis notes that
they can appear.  But contexts can nest, and in the case
of an actual argument that turns out to be an array constructor,
the permission to use a whole assumed-size array must be
rescinded.

Fixes https://github.com/llvm/llvm-project/issues/131909.
---
 flang/include/flang/Semantics/expression.h   | 12 ++++++------
 flang/lib/Semantics/expression.cpp           |  4 +++-
 flang/test/Semantics/array-constr-values.f90 |  6 +++++-
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/flang/include/flang/Semantics/expression.h b/flang/include/flang/Semantics/expression.h
index b051c486641fe..068395072266f 100644
--- a/flang/include/flang/Semantics/expression.h
+++ b/flang/include/flang/Semantics/expression.h
@@ -258,16 +258,16 @@ class ExpressionAnalyzer {
   // Builds a typed Designator from an untyped DataRef
   MaybeExpr Designate(DataRef &&);
 
-protected:
-  int IntegerTypeSpecKind(const parser::IntegerTypeSpec &);
-
-private:
   // Allows a whole assumed-size array to appear for the lifetime of
   // the returned value.
-  common::Restorer<bool> AllowWholeAssumedSizeArray() {
-    return common::ScopedSet(isWholeAssumedSizeArrayOk_, true);
+  common::Restorer<bool> AllowWholeAssumedSizeArray(bool yes = true) {
+    return common::ScopedSet(isWholeAssumedSizeArrayOk_, yes);
   }
 
+protected:
+  int IntegerTypeSpecKind(const parser::IntegerTypeSpec &);
+
+private:
   // Allows an Expr to be a null pointer.
   common::Restorer<bool> AllowNullPointer() {
     return common::ScopedSet(isNullPointerOk_, true);
diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 39a58a4e23363..74570cdb8eda0 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -1915,7 +1915,9 @@ void ArrayConstructorContext::Add(const parser::AcValue::Triplet &triplet) {
 }
 
 void ArrayConstructorContext::Add(const parser::Expr &expr) {
-  auto restorer{exprAnalyzer_.GetContextualMessages().SetLocation(expr.source)};
+  auto restorer1{
+      exprAnalyzer_.GetContextualMessages().SetLocation(expr.source)};
+  auto restorer2{exprAnalyzer_.AllowWholeAssumedSizeArray(false)};
   Push(exprAnalyzer_.Analyze(expr));
 }
 
diff --git a/flang/test/Semantics/array-constr-values.f90 b/flang/test/Semantics/array-constr-values.f90
index 6742cd35fe52d..b6558c08089c6 100644
--- a/flang/test/Semantics/array-constr-values.f90
+++ b/flang/test/Semantics/array-constr-values.f90
@@ -2,9 +2,10 @@
 ! Confirm enforcement of constraints and restrictions in 7.8
 ! C7110, C7111, C7112, C7113, C7114, C7115
 
-subroutine arrayconstructorvalues()
+subroutine arrayconstructorvalues(asize)
   integer :: intarray(4)
   integer(KIND=8) :: k8 = 20
+  integer, intent(in) :: asize(*)
 
   TYPE EMPLOYEE
     INTEGER AGE
@@ -55,6 +56,9 @@ subroutine arrayconstructorvalues()
 
   !ERROR: Item is not suitable for use in an array constructor
   intarray(1:1) = [ arrayconstructorvalues ]
+
+  !ERROR: Whole assumed-size array 'asize' may not appear here without subscripts
+  intarray = [ asize ]
 end subroutine arrayconstructorvalues
 subroutine checkC7115()
   real, dimension(10), parameter :: good1 = [(99.9, i = 1, 10)]