diff --git a/src/Language/Ruby/Assignment.hs b/src/Language/Ruby/Assignment.hs
index f61f08d3b..7f72c14cd 100644
--- a/src/Language/Ruby/Assignment.hs
+++ b/src/Language/Ruby/Assignment.hs
@@ -307,7 +307,7 @@ methodCall = makeTerm' <$> symbol MethodCall <*> children (require <|> load <|>
     nameExpression = (symbol ArgumentList <|> symbol ArgumentListWithParens) *> children expression
 
 call :: Assignment
-call = makeTerm <$> symbol Call <*> children (Expression.MemberAccess <$> expression <*> (expressions <|> args))
+call = makeTerm <$> symbol Call <*> children (Expression.MemberAccess <$> expression <*> (args <|> expressions))
   where
     args = (symbol ArgumentList <|> symbol ArgumentListWithParens) *> children expressions
 
diff --git a/src/Semantic/CLI.hs b/src/Semantic/CLI.hs
index f6e84513f..60df96e4d 100644
--- a/src/Semantic/CLI.hs
+++ b/src/Semantic/CLI.hs
@@ -53,6 +53,7 @@ arguments = info (version <*> helper <*> ((,) <$> optionsParser <*> argumentsPar
       <*> pure False -- PrintSource
       <*> pure Log.logfmtFormatter -- Formatter
       <*> pure 0 -- ProcessID
+      <*> switch (long "fail-on-warning" <> help "Fail on assignment warnings.")
     argumentsParser = (. Task.writeToOutput) . (>>=)
       <$> hsubparser (diffCommand <> parseCommand)
       <*> (   Right <$> strOption (long "output" <> short 'o' <> help "Output path, defaults to stdout")
diff --git a/src/Semantic/Log.hs b/src/Semantic/Log.hs
index 55c934de0..f472c0ad6 100644
--- a/src/Semantic/Log.hs
+++ b/src/Semantic/Log.hs
@@ -83,13 +83,14 @@ terminalFormatter Options{..} (Message level message pairs time) =
 
 -- | Options controlling logging, error handling, &c.
 data Options = Options
-  { optionsEnableColour :: Bool -- ^ Whether to enable colour formatting for logging (Only works when logging to a terminal that supports ANSI colors).
-  , optionsLevel        :: Maybe Level -- ^ What level of messages to log. 'Nothing' disabled logging.
-  , optionsRequestID    :: Maybe String -- ^ Optional request id for tracing across systems.
-  , optionsIsTerminal   :: Bool -- ^ Whether a terminal is attached (set automaticaly at runtime).
-  , optionsPrintSource  :: Bool -- ^ Whether to print the source reference when logging errors (set automatically at runtime).
-  , optionsFormatter    :: Options -> Message -> String -- ^ Log formatter to use (set automaticaly at runtime).
-  , optionsProcessID    :: CPid -- ^ ProcessID (set automaticaly at runtime).
+  { optionsEnableColour  :: Bool                         -- ^ Whether to enable colour formatting for logging (Only works when logging to a terminal that supports ANSI colors).
+  , optionsLevel         :: Maybe Level                  -- ^ What level of messages to log. 'Nothing' disabled logging.
+  , optionsRequestID     :: Maybe String                 -- ^ Optional request id for tracing across systems.
+  , optionsIsTerminal    :: Bool                         -- ^ Whether a terminal is attached (set automaticaly at runtime).
+  , optionsPrintSource   :: Bool                         -- ^ Whether to print the source reference when logging errors (set automatically at runtime).
+  , optionsFormatter     :: Options -> Message -> String -- ^ Log formatter to use (set automaticaly at runtime).
+  , optionsProcessID     :: CPid                         -- ^ ProcessID (set automaticaly at runtime).
+  , optionsFailOnWarning :: Bool
   }
 
 defaultOptions :: Options
@@ -101,6 +102,7 @@ defaultOptions = Options
   , optionsPrintSource = False
   , optionsFormatter = logfmtFormatter
   , optionsProcessID = 0
+  , optionsFailOnWarning = False
   }
 
 configureOptionsForHandle :: MonadIO io => Handle -> Options -> io Options
diff --git a/src/Semantic/Task.hs b/src/Semantic/Task.hs
index 8ccf979a8..e4287c4d0 100644
--- a/src/Semantic/Task.hs
+++ b/src/Semantic/Task.hs
@@ -51,6 +51,7 @@ import           Analysis.Decorator (decoratorWithAlgebra)
 import qualified Assigning.Assignment as Assignment
 import qualified Control.Abstract.Analysis as Analysis
 import qualified Control.Exception as Exc
+import           Control.Monad
 import           Control.Monad.Effect.Exception
 import           Control.Monad.Effect.Internal as Eff hiding (run)
 import           Control.Monad.Effect.Reader
@@ -215,6 +216,7 @@ runParser blob@Blob{..} parser = case parser of
               _ -> do
                 writeStat (Stat.increment "parse.assign_warnings" languageTag)
                 logError options Warning blob err (("task", "assign") : blobFields)
+                when (optionsFailOnWarning options) $ throwError (toException err)
           writeStat (Stat.count "parse.nodes" (length term) languageTag)
           pure term
   MarkdownParser ->