Index: flang/docs/Extensions.md
===================================================================
--- flang/docs/Extensions.md
+++ flang/docs/Extensions.md
@@ -88,6 +88,7 @@
   from sharing the same name as a symbol in its scope's host, if it
   has one.
   We accept this usage with a portability warning.
+* The argument to `RANDOM_NUMBER` may not be an assumed-size array.
 
 ## Extensions, deletions, and legacy features supported by default
 
Index: flang/lib/Evaluate/intrinsics.cpp
===================================================================
--- flang/lib/Evaluate/intrinsics.cpp
+++ flang/lib/Evaluate/intrinsics.cpp
@@ -226,7 +226,7 @@
     defaultsToSameKind, // for MatchingDefaultKIND
     defaultsToSizeKind, // for SizeDefaultKIND
     defaultsToDefaultForResult, // for DefaultingKIND
-)
+    notAssumedSize)
 
 struct IntrinsicDummyArgument {
   const char *keyword{nullptr};
@@ -811,8 +811,9 @@
         Rank::scalar, IntrinsicClass::inquiryFunction},
     {"spacing", {{"x", SameReal}}, SameReal},
     {"spread",
-        {{"source", SameType, Rank::known}, RequiredDIM,
-            {"ncopies", AnyInt, Rank::scalar}},
+        {{"source", SameType, Rank::known, Optionality::required,
+             common::Intent::In, {ArgFlag::notAssumedSize}},
+            RequiredDIM, {"ncopies", AnyInt, Rank::scalar}},
         SameType, Rank::rankPlus1, IntrinsicClass::transformationalFunction},
     {"sqrt", {{"x", SameFloating}}, SameFloating},
     {"stopped_images", {OptionalTEAM, SizeDefaultKIND}, KINDInt, Rank::vector,
@@ -1364,7 +1365,7 @@
         {}, Rank::elemental, IntrinsicClass::impureSubroutine},
     {"random_number",
         {{"harvest", AnyReal, Rank::known, Optionality::required,
-            common::Intent::Out}},
+            common::Intent::Out, {ArgFlag::notAssumedSize}}},
         {}, Rank::elemental, IntrinsicClass::impureSubroutine},
     {"random_seed",
         {{"size", DefaultInt, Rank::scalar, Optionality::optional,
@@ -1687,6 +1688,16 @@
         }
       }
     }
+    if (d.flags.test(ArgFlag::notAssumedSize)) {
+      if (auto named{ExtractNamedEntity(*arg)}) {
+        if (semantics::IsAssumedSizeArray(named->GetLastSymbol())) {
+          messages.Say(arg->sourceLocation(),
+              "The '%s=' argument to the intrinsic procedure '%s' may not be assumed-size"_err_en_US,
+              d.keyword, name);
+          return std::nullopt;
+        }
+      }
+    }
     if (arg->GetAssumedTypeDummy()) {
       // TYPE(*) assumed-type dummy argument forwarded to intrinsic
       if (d.typePattern.categorySet == AnyType &&
@@ -1971,8 +1982,7 @@
             if (semantics::IsAssumedSizeArray(named->GetLastSymbol())) {
               if (strcmp(name, "shape") == 0) {
                 messages.Say(arg->sourceLocation(),
-                    "The '%s=' argument to the intrinsic function '%s' may not be assumed-size"_err_en_US,
-                    d.keyword, name);
+                    "The 'source=' argument to the intrinsic function 'shape' may not be assumed-size"_err_en_US);
               } else {
                 messages.Say(arg->sourceLocation(),
                     "A dim= argument is required for '%s' when the array is assumed-size"_err_en_US,
Index: flang/test/Semantics/misc-intrinsics.f90
===================================================================
--- flang/test/Semantics/misc-intrinsics.f90
+++ flang/test/Semantics/misc-intrinsics.f90
@@ -13,6 +13,8 @@
     print *, ubound(arg)
     !ERROR: The 'source=' argument to the intrinsic function 'shape' may not be assumed-size
     print *, shape(arg)
+    !ERROR: The 'harvest=' argument to the intrinsic procedure 'random_number' may not be assumed-size
+    call random_number(arg)
     !ERROR: missing mandatory 'dim=' argument
     print *, lbound(scalar)
     !ERROR: 'array=' argument has unacceptable rank 0