Warn about 'export $foo'

ShellCheck/Analytics.hs

@@ -207,6 +207,7 @@ nodeChecks = [
     ,checkMaskedReturns
     ,checkInjectableFindSh
     ,checkReadWithoutR
+    ,checkExportedExpansions
     ]
 
 
@@ -3461,6 +3462,18 @@ checkReadWithoutR _ t@(T_SimpleCommand {}) | t `isUnqualifiedCommand` "read" =
         info (getId t) 2162 "read without -r will mangle backslashes."
 checkReadWithoutR _ _ = return ()
 
+prop_checkExportedExpansions1 = verify checkExportedExpansions "export $foo"
+prop_checkExportedExpansions2 = verify checkExportedExpansions "export \"$foo\""
+prop_checkExportedExpansions3 = verifyNot checkExportedExpansions "export foo"
+checkExportedExpansions _ = checkUnqualifiedCommand "export" (const check)
+  where
+    check = mapM_ checkForVariables
+    checkForVariables f =
+        case getWordParts f of
+            [t@(T_DollarBraced {})] ->
+                warn (getId t) 2163 "Exporting an expansion rather than a variable."
+            _ -> return ()
+
 
 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])