From 4e9105717ba27abbada1a20549ffc7ec9fc46917 Mon Sep 17 00:00:00 2001
From: Ilya Rezvov <rezvov.ilya@gmail.com>
Date: Mon, 6 Jun 2022 18:41:22 -0600
Subject: [PATCH] parse externref elems, but fail on validation

---
 src/Language/Wasm/Parser.y    | 11 ++++++-----
 src/Language/Wasm/Validate.hs |  2 ++
 tests/Test.hs                 |  2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/Language/Wasm/Parser.y b/src/Language/Wasm/Parser.y
index 0003310..9160142 100644
--- a/src/Language/Wasm/Parser.y
+++ b/src/Language/Wasm/Parser.y
@@ -479,11 +479,11 @@ plaininstr :: { PlainInstr }
             Nothing -> TableInit (Index 0) $2
             Just elemIdx -> TableInit $2 elemIdx
     }
-    | 'table.get' index              { TableGet $2 }
-    | 'table.set' index              { TableSet $2 }
-    | 'table.copy' index index       { TableCopy $2 $3 }
-    | 'table.size' index             { TableSize $2 }
-    | 'table.grow' index             { TableGrow $2 }
+    | 'table.get' opt(index)         { TableGet (fromMaybe (Index 0) $2) }
+    | 'table.set' opt(index)         { TableSet (fromMaybe (Index 0) $2) }
+    | 'table.copy' opt(index) opt(index) { TableCopy (fromMaybe (Index 0) $2) (fromMaybe (Index 0) $3) }
+    | 'table.size' opt(index)        { TableSize (fromMaybe (Index 0) $2) }
+    | 'table.grow' opt(index)        { TableGrow (fromMaybe (Index 0) $2) }
     | 'elem.drop' index              { ElemDrop $2 }
     -- numeric instructions
     | 'i32.const' int32              { I32Const $2 }
@@ -977,6 +977,7 @@ elem1_active_offset :: { ([Instruction], ElemType, [[Instruction]]) }
 elemlist :: { (ElemType, [[Instruction]]) }
     : 'func' list(index) { (FuncRef, funcIndexToExpr $2) }
     | 'funcref' list(elemexpr) { (FuncRef, $2) }
+    | 'externref' { (ExternRef, []) }
     | list(index) { (FuncRef, funcIndexToExpr $1) }
 
 elemexpr :: { [Instruction] }
diff --git a/src/Language/Wasm/Validate.hs b/src/Language/Wasm/Validate.hs
index c8f068b..315e6bd 100644
--- a/src/Language/Wasm/Validate.hs
+++ b/src/Language/Wasm/Validate.hs
@@ -615,6 +615,8 @@ elemsShouldBeValid m@Module { elems, functions, tables, imports } =
     where
         isElemValid :: Ctx -> ElemSegment -> ValidationResult
         isElemValid ctx (ElemSegment elemType mode elements) = do
+            unless (elemType == FuncRef)
+                $ throwError $ RefTypeMismatch FuncRef elemType
             forM_ elements $ \elem -> runChecker ctx $ do
                 arr <- getExpressionType elem
                 isConstExpression elem
diff --git a/tests/Test.hs b/tests/Test.hs
index afdd538..eb17f3c 100644
--- a/tests/Test.hs
+++ b/tests/Test.hs
@@ -19,7 +19,7 @@ main = do
   files <-
     filter (not . List.isPrefixOf "simd") . filter (List.isSuffixOf ".wast")
       <$> Directory.listDirectory "tests/spec"
-  let files = ["table_copy.wast"]
+  let files = ["table_get.wast"]
   scriptTestCases <- (`mapM` files) $ \file -> do
     test <- LBS.readFile ("tests/spec/" ++ file)
     return $ testCase file $ do