From 007b1e966d4234f2fbdc8f21d53b27dec0060b5e Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Tue, 16 Aug 2022 23:37:40 +0100
Subject: Unexpected return error

---
 src/Compiler.hs  |  2 +-
 src/Error.hs     |  3 +++
 test/Language.hs | 27 ++++++++++++++++++++++++++-
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/Compiler.hs b/src/Compiler.hs
index da25c5d..413a041 100644
--- a/src/Compiler.hs
+++ b/src/Compiler.hs
@@ -121,7 +121,7 @@ compile x = do
     (A.Return value pos) -> do
       (ev, errs) <- get
       case getSyml ev "$fn$" of
-        Nothing -> addError $ Error "return without function call" pos
+        Nothing -> addError $ UnexpectedReturn "return without function call" pos
         Just (_, A.FuncType _ rtyp, _) -> do
           r <- typecheckReturn value rtyp
           case r of
diff --git a/src/Error.hs b/src/Error.hs
index b528f9e..1363120 100644
--- a/src/Error.hs
+++ b/src/Error.hs
@@ -6,6 +6,7 @@ import Text.Parsec.Error (ParseError, errorMessages, showErrorMessages)
 
 data Error
   = TypeError String SourcePos
+  | UnexpectedReturn String SourcePos
   | Error String SourcePos
   deriving (Eq)
 
@@ -15,6 +16,8 @@ instance Show Error where
   -- XXX: can we do this differently?
   show (TypeError message pos) =
     show pos ++ " error: " ++ message
+  show (UnexpectedReturn message pos) =
+    show pos ++ " error: " ++ message
 
 showParserError :: ParseError -> String
 showParserError error =
diff --git a/test/Language.hs b/test/Language.hs
index 7892c16..9da3124 100644
--- a/test/Language.hs
+++ b/test/Language.hs
@@ -183,4 +183,29 @@ testCase12 =
         Nothing -> assertFailure "expected error, didn't happen"
         Just (E.TypeError _ _) -> return $ ()
 
-language = [testCase1, testCase2, testCase3, testCase4, testCase5, testCase6, testCase7, testCase8, testCase9, testCase10, testCase11, testCase12]
+testCase13 =
+  TestLabel "return without function" $
+    TestCase $ do
+      e <-
+        expectError
+          "module main\n\
+          \return;"
+      case e of
+        Nothing -> assertFailure "expected error, didn't happen"
+        Just (E.UnexpectedReturn _ _) -> return $ ()
+
+language =
+  [ testCase1,
+    testCase2,
+    testCase3,
+    testCase4,
+    testCase5,
+    testCase6,
+    testCase7,
+    testCase8,
+    testCase9,
+    testCase10,
+    testCase11,
+    testCase12,
+    testCase13
+  ]
-- 
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