diff --git a/python/mozbuild/mozbuild/code_analysis/mach_commands.py b/python/mozbuild/mozbuild/code_analysis/mach_commands.py
index c3a0d1a6f933..bc5604f0dbe6 100644
--- a/python/mozbuild/mozbuild/code_analysis/mach_commands.py
+++ b/python/mozbuild/mozbuild/code_analysis/mach_commands.py
@@ -2162,6 +2162,7 @@ class StaticAnalysis(MachCommandBase):
 
         max_workers = multiprocessing.cpu_count()
 
+        rc = 0
         with concurrent.futures.ThreadPoolExecutor(max_workers=max_workers) as executor:
             futures = []
             for command in commands:
@@ -2174,6 +2175,11 @@ class StaticAnalysis(MachCommandBase):
                         ensure_exit_code=False,
                     )
                 )
+            for thread in concurrent.futures.as_completed(futures):
+                if thread.result() != 0:
+                    rc = thread.result()
+
+        return rc
 
     @Command(
         "clang-format",
diff --git a/taskcluster/ci/source-test/clang.yml b/taskcluster/ci/source-test/clang.yml
index 867911967723..9fd2164fcb45 100644
--- a/taskcluster/ci/source-test/clang.yml
+++ b/taskcluster/ci/source-test/clang.yml
@@ -99,3 +99,19 @@ external:
             - type: file
               name: public/code-review/clang-tidy.json
               path: /builds/worker/clang-tidy.json
+
+non-unified:
+    description: Run syntax test for non-unified build on C/C++ files.
+    treeherder:
+        symbol: cpp(non-unified)
+    attributes:
+        code-review: false
+    run-on-projects: [mozilla-central]
+    run:
+        cwd: '{checkout}'
+        command: >-
+            source taskcluster/scripts/misc/source-test-clang-setup.sh &&
+            taskcluster/scripts/misc/source-test-clang-non-unified.sh
+    fetches:
+        toolchain:
+            - linux64-clang-tidy
diff --git a/taskcluster/scripts/misc/source-test-clang-non-unified.sh b/taskcluster/scripts/misc/source-test-clang-non-unified.sh
new file mode 100755
index 000000000000..13bbc87079ec
--- /dev/null
+++ b/taskcluster/scripts/misc/source-test-clang-non-unified.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+NON_UNIFIED_CFG=$GECKO_PATH/build/non-unified-compat
+
+while IFS= read -r directory
+do
+  echo "Running non-unified compile test for: $directory"
+  ./mach static-analysis check-syntax $directory
+  if [ $? -ne 0 ]; then
+    # If failure do not continue with the rest of the directories
+    exit 1
+  fi
+done < $NON_UNIFIED_CFG
diff --git a/taskcluster/scripts/misc/source-test-clang-setup.sh b/taskcluster/scripts/misc/source-test-clang-setup.sh
index c457cfb290d3..a8288e5a364f 100755
--- a/taskcluster/scripts/misc/source-test-clang-setup.sh
+++ b/taskcluster/scripts/misc/source-test-clang-setup.sh
@@ -16,6 +16,8 @@ cat <<EOT >> $MOZCONFIG
 ac_add_options --enable-debug
 # Enable GC zeal, a testing and debugging feature that helps find GC-related bugs in JSAPI applications.
 ac_add_options --enable-gczeal
+# Do not treat warnings as errors
+ac_add_options --disable-warnings-as-errors
 EOT
 
 # Mach lookup clang-tidy in clang-tools