diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -486,7 +486,7 @@
     {"image_status", {{"image", SameInt}, OptionalTEAM}, DefaultInt},
     {"index",
         {{"string", SameChar}, {"substring", SameChar},
-            {"back", AnyLogical, Rank::scalar, Optionality::optional},
+            {"back", AnyLogical, Rank::elemental, Optionality::optional},
             DefaultingKIND},
         KINDInt},
     {"int", {{"a", AnyNumeric, Rank::elementalOrBOZ}, DefaultingKIND}, KINDInt},
diff --git a/flang/test/Evaluate/folding05.f90 b/flang/test/Evaluate/folding05.f90
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001