diff --git a/flang/lib/Evaluate/fold-implementation.h b/flang/lib/Evaluate/fold-implementation.h
--- a/flang/lib/Evaluate/fold-implementation.h
+++ b/flang/lib/Evaluate/fold-implementation.h
@@ -1113,7 +1113,13 @@
         if (rightExpr.Rank() > 0) {
           if (std::optional<Shape> rightShape{GetShape(context, rightExpr)}) {
             if (auto right{AsFlatArrayConstructor(rightExpr)}) {
-              CheckConformance(context.messages(), *leftShape, *rightShape);
+              if (CheckConformance(
+                      context.messages(), *leftShape, *rightShape)) {
+                return MapOperation(context, std::move(f), *leftShape,
+                    std::move(*left), std::move(*right));
+              } else {
+                return std::nullopt;
+              }
               return MapOperation(context, std::move(f), *leftShape,
                   std::move(*left), std::move(*right));
             }
diff --git a/flang/lib/Evaluate/shape.cpp b/flang/lib/Evaluate/shape.cpp
--- a/flang/lib/Evaluate/shape.cpp
+++ b/flang/lib/Evaluate/shape.cpp
@@ -682,6 +682,8 @@
   return std::nullopt;
 }
 
+// Check conformance of the passed shapes.  Only return true if we can verify
+// that they conform
 bool CheckConformance(parser::ContextualMessages &messages, const Shape &left,
     const Shape &right, const char *leftIs, const char *rightIs) {
   int n{GetRank(left)};
@@ -693,15 +695,16 @@
       return false;
     } else {
       for (int j{0}; j < n; ++j) {
-        if (auto leftDim{ToInt64(left[j])}) {
-          if (auto rightDim{ToInt64(right[j])}) {
-            if (*leftDim != *rightDim) {
-              messages.Say("Dimension %1$d of %2$s has extent %3$jd, "
-                           "but %4$s has extent %5$jd"_err_en_US,
-                  j + 1, leftIs, *leftDim, rightIs, *rightDim);
-              return false;
-            }
-          }
+        auto leftDim{ToInt64(left[j])};
+        auto rightDim{ToInt64(right[j])};
+        if (!leftDim || !rightDim) {
+          return false;
+        }
+        if (*leftDim != *rightDim) {
+          messages.Say("Dimension %1$d of %2$s has extent %3$jd, "
+                       "but %4$s has extent %5$jd"_err_en_US,
+              j + 1, leftIs, *leftDim, rightIs, *rightDim);
+          return false;
         }
       }
     }
diff --git a/flang/test/Semantics/shape.f90 b/flang/test/Semantics/shape.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/shape.f90
@@ -0,0 +1,41 @@
+! RUN: %S/test_errors.sh %s %t %f18
+! Test comparisons that use the intrinsic SHAPE() as an operand
+program testShape
+contains
+  subroutine sub1(arrayDummy)
+    integer :: arrayDummy(:)
+    integer, allocatable :: arrayDeferred(:)
+    integer :: arrayLocal(2) = [88, 99]
+    if (all(shape(arrayDummy)==shape(8))) then
+      print *, "hello"
+    end if
+    if (all(shape(27)==shape(arrayDummy))) then
+      print *, "hello"
+    end if
+    if (all(64==shape(arrayDummy))) then
+      print *, "hello"
+    end if
+    if (all(shape(arrayDeferred)==shape(8))) then
+      print *, "hello"
+    end if
+    if (all(shape(27)==shape(arrayDeferred))) then
+      print *, "hello"
+    end if
+    if (all(64==shape(arrayDeferred))) then
+      print *, "hello"
+    end if
+    !ERROR: Dimension 1 of left operand has extent 1, but right operand has extent 0
+    !ERROR: Dimension 1 of left operand has extent 1, but right operand has extent 0
+    if (all(shape(arrayLocal)==shape(8))) then
+      print *, "hello"
+    end if
+    !ERROR: Dimension 1 of left operand has extent 0, but right operand has extent 1
+    !ERROR: Dimension 1 of left operand has extent 0, but right operand has extent 1
+    if (all(shape(27)==shape(arrayLocal))) then
+      print *, "hello"
+    end if
+    if (all(64==shape(arrayLocal))) then
+      print *, "hello"
+    end if
+  end subroutine sub1
+end program testShape