diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 44e868225..86598985a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -46,6 +46,8 @@ jobs:
   checks:
     runs-on: ubuntu-20.04
     needs: preBuild
+    outputs:
+      warnings: ${{ steps.cppcheck.outputs.warnings }}
 
     steps:
       - name: Checkout repository
@@ -53,17 +55,21 @@ jobs:
         with:
           submodules: true
       - name: Run cppcheck
+        id: cppcheck
         run: |
           sudo apt install cppcheck
+          sudo cpan Path::Class
           cppcheck --template=gcc --inline-suppr --std=c++14 --enable=style,unusedFunction -i externals \
                    --suppressions-list=cppcheck.supp --library=qt.cfg --library=posix.cfg . | tee error.log
-          ls -l error.log
+          perl scripts/warnings.pl error.log
 
   buildLinux:
     runs-on: ubuntu-16.04
     needs: preBuild
     env:
       BITROCK_BUILDER: ~/installbuilder/bin/builder
+    outputs:
+      warnings: ${{ steps.warnings.outputs.warnings }}
 
     steps:
       - name: Install Qt
@@ -80,6 +86,7 @@ jobs:
         run: |
           sudo apt install doxygen graphviz libglu1-mesa-dev libopus-dev libsodium-dev libpulse-dev libdbus-1-dev libevent-dev
           pip3 install tee
+          sudo cpan Path::Class
       - name: Checkout repository
         uses: actions/checkout@v2
         with:
@@ -99,12 +106,14 @@ jobs:
         if: ${{ ! (env.do_symbols == 'true' && env.do_vatsim_key == 'true') }}
         run: |
           python3 -u scripts/build.py -w 64 -t gcc -d -j2 -e $eol_months -q "SWIFT_CONFIG_JSON+=$vatsim_key_file"
-          ls -l error.log
       - name: Build swift (with symbols)
         if: ${{ env.do_symbols == 'true' && env.do_vatsim_key == 'true' }}
         run: |
           python3 -u scripts/build.py -w 64 -t gcc -d -j2 -e $eol_months -q "SWIFT_CONFIG_JSON+=$vatsim_key_file" --upload
-          ls -l error.log
+      - name: Check warnings
+        id: warnings
+        run: |
+          perl scripts/warnings.pl error.log
       - name: Upload installer
         uses: actions/upload-artifact@v2
         with:
@@ -127,6 +136,8 @@ jobs:
     needs: preBuild
     env:
       BITROCK_BUILDER: "$(USERPROFILE)/installbuilder/bin/builder-cli.exe"
+    outputs:
+      warnings: ${{ steps.warnings.outputs.warnings }}
 
     steps:
       - name: Install Qt
@@ -162,12 +173,14 @@ jobs:
         if: ${{ ! (env.do_symbols == 'true' && env.do_vatsim_key == 'true') }}
         run: |
           python.exe -u scripts\build.py -w 64 -t msvc -d -e $env:eol_months -q "SWIFT_CONFIG_JSON+=$env:vatsim_key_file"
-          dir error.log
       - name: Build swift (with symbols)
         if: ${{ env.do_symbols == 'true' && env.do_vatsim_key == 'true' }}
         run: |
           python.exe -u scripts\build.py -w 64 -t msvc -d -e $env:eol_months -q "SWIFT_CONFIG_JSON+=$env:vatsim_key_file" --upload
-          dir error.log
+      - name: Check warnings
+        id: warnings
+        run: |
+          perl scripts/warnings.pl error.log
       - name: Upload installer
         uses: actions/upload-artifact@v2
         with:
@@ -190,6 +203,8 @@ jobs:
     needs: preBuild
     env:
       BITROCK_BUILDER: "$(USERPROFILE)/installbuilder/bin/builder-cli.exe"
+    outputs:
+      warnings: ${{ steps.warnings.outputs.warnings }}
 
     steps:
       - name: Install Qt
@@ -225,12 +240,14 @@ jobs:
         if: ${{ ! (env.do_symbols == 'true' && env.do_vatsim_key == 'true') }}
         run: |
           python.exe -u scripts\build.py -w 32 -t msvc -d -e $env:eol_months -q "SWIFT_CONFIG_JSON+=$env:vatsim_key_file"
-          dir error.log
       - name: Build swift (with symbols)
         if: ${{ env.do_symbols == 'true' && env.do_vatsim_key == 'true' }}
         run: |
           python.exe -u scripts\build.py -w 32 -t msvc -d -e $env:eol_months -q "SWIFT_CONFIG_JSON+=$env:vatsim_key_file" --upload
-          dir error.log
+      - name: Check warnings
+        id: warnings
+        run: |
+          perl scripts/warnings.pl error.log
       - name: Upload installer
         uses: actions/upload-artifact@v2
         with:
@@ -253,6 +270,8 @@ jobs:
     needs: preBuild
     env:
       BITROCK_BUILDER: /Applications/installbuilder/bin/Builder.app/Contents/MacOS/installbuilder.sh
+    outputs:
+      warnings: ${{ steps.warnings.outputs.warnings }}
 
     steps:
       - name: Install Qt
@@ -274,6 +293,7 @@ jobs:
         run: |
           pip3 install requests
           pip3 install tee
+          cpan Path::Class
       - name: Checkout repository
         uses: actions/checkout@v2
         with:
@@ -293,12 +313,14 @@ jobs:
         if: ${{ ! (env.do_symbols == 'true' && env.do_vatsim_key == 'true') }}
         run: |
           python3 -u scripts/build.py -w 64 -t clang -d -j2 -e $eol_months -q "SWIFT_CONFIG_JSON+=$vatsim_key_file"
-          ls -l error.log
       - name: Build swift (with symbols)
         if: ${{ env.do_symbols == 'true' && env.do_vatsim_key == 'true' }}
         run: |
           python3 -u scripts/build.py -w 64 -t clang -d -j2 -e $eol_months -q "SWIFT_CONFIG_JSON+=$vatsim_key_file" --upload
-          ls -l error.log
+      - name: Check warnings
+        id: warnings
+        run: |
+          perl scripts/warnings.pl error.log
       - name: Upload installer
         uses: actions/upload-artifact@v2
         with:
@@ -351,11 +373,13 @@ jobs:
       - name: Prepare Discord message
         run: |
           result=SUCCESS
-          echo ${{ join(needs.*.result, ' ') }} | grep -q cancel && result=CANCELLED
+          expr ${{ join(needs.*.outputs.warnings, ' + ') }}      && result=WARNING
           echo ${{ join(needs.*.result, ' ') }} | grep -q fail   && result=FAILED
+          echo ${{ join(needs.*.result, ' ') }} | grep -q cancel && result=CANCELLED
           [[ $result = SUCCESS   ]] && emoji=white_check_mark
-          [[ $result = CANCELLED ]] && emoji=grey_question
+          [[ $result = WARNING   ]] && emoji=warning
           [[ $result = FAILED    ]] && emoji=x
+          [[ $result = CANCELLED ]] && emoji=grey_question
           echo "::set-env name=result::$result"
           echo "::set-env name=emoji::$emoji"
       - name: Send Discord message
diff --git a/scripts/warnings.pl b/scripts/warnings.pl
new file mode 100644
index 000000000..d1adb0b41
--- /dev/null
+++ b/scripts/warnings.pl
@@ -0,0 +1,74 @@
+#!/usr/bin/perl
+#
+# Convert C++ compiler warnings into Github Actions workflow commands
+#
+# Copyright (C) 2020 swift Project Community / contributors
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+use strict;
+use warnings;
+use Path::Class;
+
+my %cmds;
+while (<<>>)
+{
+    chomp;
+    my %result = extractWarning($_);
+    next if not %result;
+    $result{file} = toRelativePath($result{file})->as_foreign('Unix');
+    if (exists $result{line}) {
+        ++$cmds{"::warning file=$result{file},line=$result{line}::$result{msg}"};
+    } else {
+        ++$cmds{"::warning file=$result{file}::$result{msg}"};
+    }
+}
+my @cmds = sort keys %cmds;
+my $count = scalar @cmds;
+print "$_\n" for @cmds;
+print "::set-output name=warnings::$count\n";
+
+sub extractWarning
+{
+    my $line = shift;
+    my %result = extractGccWarning($line);
+    return %result if %result;
+    return extractMsvcWarning($line);
+}
+
+sub extractGccWarning
+{
+    my $line = shift;
+    $line =~ m(^\s*(?<loc>.*?): warning: (?<msg>.*)$) or return ();
+    my ($loc, $msg) = @+{ qw(loc msg) };
+    $loc =~ m(^(?<file>.*?):(?<loc>[0-9:]+)$) or return (file => $loc, msg => $msg);
+    my ($file, $loc) = ($+{file}, split ':', $+{loc});
+    return (file => $file, line => $loc, msg => $msg);
+}
+
+sub extractMsvcWarning
+{
+    my $line = shift;
+    $line =~ m(^\s*(?<loc>.*?): warning (?<msg>[A-Z]+[0-9]+: .*)$) or return ();
+    my ($loc, $msg) = @+{ qw(loc msg) };
+    $loc =~ m(^(?<file>.*)\((?<loc>[0-9,]+)\)$) or return (file => $loc, msg => $msg);
+    my ($file, $loc) = ($+{file}, split ',', $+{loc});
+    return (file => $file, line => $loc, msg => $msg);
+}
+
+sub toRelativePath
+{
+    my $path = shift;
+    my $file = file($path);
+    return $file if $file->is_relative;
+    return $file->relative if dir()->absolute()->subsumes($file);
+    return $file;
+}