Fix SC2317 false positive on return ||: when script is not sourced

Co-authored-by: dotysan <5060170+dotysan@users.noreply.github.com>

Author: Copilot

src/ShellCheck/Analytics.hs

@@ -5049,6 +5049,9 @@ prop_checkCommandIsUnreachable2 = verify checkCommandIsUnreachable "die() { exit
 prop_checkCommandIsUnreachable3 = verifyNot checkCommandIsUnreachable "foo; bar || exit; baz"
 prop_checkCommandIsUnreachable4 = verifyNot checkCommandIsUnreachable "f() { foo; };    # Maybe sourced"
 prop_checkCommandIsUnreachable5 = verify checkCommandIsUnreachable "f() { foo; }; exit  # Not sourced"
+prop_checkCommandIsUnreachable6 = verifyNot checkCommandIsUnreachable "return || :; echo 'reachable'"
+prop_checkCommandIsUnreachable7 = verifyNot checkCommandIsUnreachable "return; echo 'reachable when not in function'"
+prop_checkCommandIsUnreachable8 = verify checkCommandIsUnreachable "f() { return; echo unreachable; }"
 checkCommandIsUnreachable params t =
     case t of
         T_Pipeline {} -> sequence_ $ do

src/ShellCheck/CFG.hs

@@ -983,13 +983,20 @@ handleCommand cmd vars args literalCmd = do
 
     handleReturn = do
         returnTarget <- reader cfReturnTarget
-        case returnTarget of
-            Nothing -> error $ pleaseReport "missing return target"
-            Just target -> do
+        isFunction <- reader cfIsFunction
+        case (returnTarget, isFunction) of
+            (Nothing, _) -> error $ pleaseReport "missing return target"
+            (Just target, True) -> do
+                -- In a function: return actually returns, making subsequent code unreachable
                 ret <- newNode CFStructuralNode
                 link ret target CFEFlow
                 unreachable <- newNode CFUnreachable
                 return $ Range ret unreachable
+            (Just _, False) -> do
+                -- Not in a function: return will fail and execution continues
+                -- Treat it like a regular command that sets exit code
+                ret <- newNodeRange $ CFSetExitCode (getId cmd)
+                return ret
 
     handleUnset (cmd NE.:| args) = do
         case () of