diff --git a/CHANGELOG.md b/CHANGELOG.md
index f85e639f9..6b9e5b54c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - [C API tutorial](doc/c_tutorial/c_tutorial.rst), kindly contributed by @smadaminov.
 
+### Bug fix
+
+- Compiler crashed when differentiation or delay operators were applied to
+  relations declared outside of the main module of the program.
+
 ## [0.37.0] - Feb 15, 2021
 
 ### Language improvements
diff --git a/src/Language/DifferentialDatalog/Compile.hs b/src/Language/DifferentialDatalog/Compile.hs
index 454fd7135..6de4c958a 100644
--- a/src/Language/DifferentialDatalog/Compile.hs
+++ b/src/Language/DifferentialDatalog/Compile.hs
@@ -624,7 +624,11 @@ simplifyDelayedRels d =
            delayed_rels d'
     where
     mk_delayed_rel_name :: (String, Delay) -> String
-    mk_delayed_rel_name (rel, del) = "__" ++ show (delayDelay del) ++ "_" ++ rel
+    mk_delayed_rel_name (rel, del) = scoped rel_scope $ "__" ++ show (delayDelay del) ++ "_" ++ rel_name
+        where
+        rel_scope = nameScope rel
+        rel_name = nameLocalStr rel
+
     -- Find all delayed rels in the program, replacing each occurrence
     -- of 'R-n' with '__n_R'.
     (delayed_rels, d') = runState
@@ -682,7 +686,10 @@ simplifyDifferentiation d =
            diff_rels d'
     where
     mk_diff_rel_name :: String -> String
-    mk_diff_rel_name rname = "__diff_" ++ rname
+    mk_diff_rel_name rname = scoped rel_scope $ "__diff_" ++ rel_name
+        where
+        rel_scope = nameScope rname
+        rel_name = nameLocalStr rname
     -- Find all differentiated rels in the program, replacing each occurrence
     -- of 'R'' with '__diff_R'.
     (diff_rels, d') = runState
diff --git a/src/Language/DifferentialDatalog/Module.hs b/src/Language/DifferentialDatalog/Module.hs
index ee5a3ebfc..1f9ea779d 100644
--- a/src/Language/DifferentialDatalog/Module.hs
+++ b/src/Language/DifferentialDatalog/Module.hs
@@ -143,7 +143,6 @@ stdImports = map stdImport stdLibs
 parseDatalogProgram :: [FilePath] -> Bool -> String -> FilePath -> ExceptT String IO ([DatalogModule], DatalogProgram, M.Map ModuleName (Doc, Doc, Doc))
 parseDatalogProgram roots import_std fdata fname = do
     roots' <- lift $ nub <$> mapM canonicalizePath roots
-    -- TODO: parseDatalogProgram should return ExceptT.
     prog <- parseDatalogString fdata fname
     let prog' = if import_std
                    then prog { progImports = stdImports ++ progImports prog }
diff --git a/src/Language/DifferentialDatalog/Parse.hs b/src/Language/DifferentialDatalog/Parse.hs
index fd43ba13f..89cce4d19 100644
--- a/src/Language/DifferentialDatalog/Parse.hs
+++ b/src/Language/DifferentialDatalog/Parse.hs
@@ -58,7 +58,7 @@ import Language.DifferentialDatalog.Ops
 import Language.DifferentialDatalog.Error
 import {-# SOURCE #-} Language.DifferentialDatalog.Expr
 
--- parse a string containing a datalog program and produce the intermediate representation
+-- parse a string containing a DDlog program and produce the intermediate representation.
 parseDatalogString :: String -> String -> ExceptT String IO DatalogProgram
 parseDatalogString program file = do
   case parse datalogGrammar file program of
diff --git a/test/datalog_tests/modules.dl b/test/datalog_tests/modules.dl
index 31fd1c06a..b6ff2ab34 100644
--- a/test/datalog_tests/modules.dl
+++ b/test/datalog_tests/modules.dl
@@ -2,6 +2,8 @@ import foolib::lib
 import foolib::ns1::m1 as m1
 import foolib::ns1::m2 as m2
 import redist
+// Make sure we can compile streaming code that lives in a module.
+import streams
 
 input relation Rmain(f1: Tlib, f2: m1::T1)
 output relation Rout(f1: bool, f2: bigint)
diff --git a/test/datalog_tests/stream.dat b/test/datalog_tests/streams.dat
similarity index 100%
rename from test/datalog_tests/stream.dat
rename to test/datalog_tests/streams.dat
diff --git a/test/datalog_tests/stream.dl b/test/datalog_tests/streams.dl
similarity index 100%
rename from test/datalog_tests/stream.dl
rename to test/datalog_tests/streams.dl
diff --git a/test/datalog_tests/stream.dump.expected b/test/datalog_tests/streams.dump.expected
similarity index 100%
rename from test/datalog_tests/stream.dump.expected
rename to test/datalog_tests/streams.dump.expected
diff --git a/test/datalog_tests/test-stream.sh b/test/datalog_tests/test-stream.sh
index f0a2e214c..ae9bbbabc 100755
--- a/test/datalog_tests/test-stream.sh
+++ b/test/datalog_tests/test-stream.sh
@@ -2,7 +2,7 @@
 
 set -e
 
-./run-test.sh stream release
+./run-test.sh streams release
 
 run_test() {
     echo Running mem leak test for $1 iterations.
@@ -13,7 +13,7 @@ run_test() {
         insert Chunk(\"{\\\"fild\\\": $i}\"),
         commit dump_changes;"
     done) |
-        /usr/bin/time -o stream_mem -f "%M" ./stream_ddlog/target/release/stream_cli -w 4 --no-store > stream_mem.dump
+        /usr/bin/time -o stream_mem -f "%M" ./streams_ddlog/target/release/streams_cli -w 4 --no-store > stream_mem.dump
 }
 
 run_memleak_test() {
@@ -50,7 +50,7 @@ run_stream_query_test() {
         done
         echo "commit dump_changes;"
     done) > stream_bench.dat
-    /usr/bin/time ./stream_ddlog/target/release/stream_cli -w $3 --no-store < stream_bench.dat > stream_stream_queries.dump
+    /usr/bin/time ./streams_ddlog/target/release/streams_cli -w $3 --no-store < stream_bench.dat > stream_stream_queries.dump
 
 }
 
@@ -82,7 +82,7 @@ run_rel_query_test() {
         echo "commit dump_changes;"
 
     done) > stream_bench.dat
-    /usr/bin/time ./stream_ddlog/target/release/stream_cli -w $3 --no-store < stream_bench.dat > stream_rel_queries.dump
+    /usr/bin/time ./streams_ddlog/target/release/streams_cli -w $3 --no-store < stream_bench.dat > stream_rel_queries.dump
 
 }