[flang] Catch whole assumed-size array as RHS (llvm#132819)

The right-hand side expression of an intrinsic assignment statement may
not be the name of an assumed-size array dummy argument.

Author: klausler

flang/include/flang/Semantics/expression.h

@@ -257,6 +257,7 @@ class ExpressionAnalyzer {
 
   // Builds a typed Designator from an untyped DataRef
   MaybeExpr Designate(DataRef &&);
+  void CheckForWholeAssumedSizeArray(parser::CharBlock, const Symbol *);
 
   // Allows a whole assumed-size array to appear for the lifetime of
   // the returned value.

flang/lib/Semantics/expression.cpp

@@ -1077,20 +1077,24 @@ MaybeExpr ExpressionAnalyzer::Analyze(const parser::Name &n) {
           n.symbol->attrs().reset(semantics::Attr::VOLATILE);
         }
       }
-      if (!isWholeAssumedSizeArrayOk_ &&
-          semantics::IsAssumedSizeArray(
-              ResolveAssociations(*n.symbol))) { // C1002, C1014, C1231
-        AttachDeclaration(
-            SayAt(n,
-                "Whole assumed-size array '%s' may not appear here without subscripts"_err_en_US,
-                n.source),
-            *n.symbol);
-      }
+      CheckForWholeAssumedSizeArray(n.source, n.symbol);
       return Designate(DataRef{*n.symbol});
     }
   }
 }
 
+void ExpressionAnalyzer::CheckForWholeAssumedSizeArray(
+    parser::CharBlock at, const Symbol *symbol) {
+  if (!isWholeAssumedSizeArrayOk_ && symbol &&
+      semantics::IsAssumedSizeArray(ResolveAssociations(*symbol))) {
+    AttachDeclaration(
+        SayAt(at,
+            "Whole assumed-size array '%s' may not appear here without subscripts"_err_en_US,
+            symbol->name()),
+        *symbol);
+  }
+}
+
 MaybeExpr ExpressionAnalyzer::Analyze(const parser::NamedConstant &n) {
   auto restorer{GetContextualMessages().SetLocation(n.v.source)};
   if (MaybeExpr value{Analyze(n.v)}) {
@@ -3362,7 +3366,8 @@ const Assignment *ExpressionAnalyzer::Analyze(const parser::AssignmentStmt &x) {
     ArgumentAnalyzer analyzer{*this};
     const auto &variable{std::get<parser::Variable>(x.t)};
     analyzer.Analyze(variable);
-    analyzer.Analyze(std::get<parser::Expr>(x.t));
+    const auto &rhsExpr{std::get<parser::Expr>(x.t)};
+    analyzer.Analyze(rhsExpr);
     std::optional<Assignment> assignment;
     if (!analyzer.fatalErrors()) {
       auto restorer{GetContextualMessages().SetLocation(variable.GetSource())};
@@ -3392,6 +3397,8 @@ const Assignment *ExpressionAnalyzer::Analyze(const parser::AssignmentStmt &x) {
             }
           }
         }
+        CheckForWholeAssumedSizeArray(
+            rhsExpr.source, UnwrapWholeSymbolDataRef(analyzer.GetExpr(1)));
       }
       assignment.emplace(analyzer.MoveExpr(0), analyzer.MoveExpr(1));
       if (procRef) {

flang/test/Semantics/assign04.f90

@@ -99,12 +99,15 @@ subroutine s5()
 
 subroutine s6(x)
   integer :: x(*)
+  integer, allocatable :: ja(:)
   x(1:3) = [1, 2, 3]
   x(:3) = [1, 2, 3]
   !ERROR: Assumed-size array 'x' must have explicit final subscript upper bound value
   x(:) = [1, 2, 3]
   !ERROR: Whole assumed-size array 'x' may not appear here without subscripts
   x = [1, 2, 3]
+  !ERROR: Whole assumed-size array 'x' may not appear here without subscripts
+  ja = x
   associate (y => x) ! ok
     !ERROR: Whole assumed-size array 'y' may not appear here without subscripts
     y = [1, 2, 3]