purescript-lua · Unisay · Jul 6, 2026 · Jul 4, 2026 · Jul 4, 2026 · Jul 5, 2026
diff --git a/lib/Language/PureScript/Backend/Lua.hs b/lib/Language/PureScript/Backend/Lua.hs
@@ -209,11 +209,13 @@ fromIR foreigns topLevelNames modname ir = case ir of
       Lua.functionCall (Lua.varName Fixture.objectUpdateName) [obj, vals]
   -- See Note [Nullary functions and Prim.undefined]
   IR.Abs _ann param expr → do
-    e ← goExp expr
+    body ← go expr
     let luaParams = case param of
           IR.ParamUnused _ann → []
           IR.ParamNamed _ann name → [ParamNamed (fromName name)]
-    pure . Right $ Lua.functionDef luaParams [Lua.return e]
+    pure . Right $ case body of
+      Left chunk → Lua.functionDef luaParams chunk
+      Right e → Lua.functionDef luaParams [Lua.return e]
   IR.App _ann expr arg → do
     e ← goExp expr
     Right . Lua.functionCall e <$> case arg of

diff --git a/lib/Language/PureScript/Backend/Lua/Optimizer.hs b/lib/Language/PureScript/Backend/Lua/Optimizer.hs
@@ -50,8 +50,7 @@ optimizeExpression = foldr (>>>) identity rewriteRulesInOrder
 
 rewriteRulesInOrder ∷ [RewriteRule]
 rewriteRulesInOrder =
-  [ removeScopeWhenInsideEmptyFunction
-  , reduceTableDefinitionAccessor
+  [ reduceTableDefinitionAccessor
   , foldFieldProjectionThroughScopeCall
   ]
 
@@ -63,14 +62,6 @@ rewriteExpWithRule rule = everywhereExp rule identity
 --------------------------------------------------------------------------------
 -- Rewrite rules for expressions -----------------------------------------------
 
-removeScopeWhenInsideEmptyFunction ∷ RewriteRule
-removeScopeWhenInsideEmptyFunction = \case
-  Function
-    outerArgs
-    [Ann (Return (Ann (FunctionCall (Ann (Function [] body)) [])))] →
-      Function outerArgs body
-  e → e
-
 {- | Rewrites '{ foo = 1, bar = 2 }.foo' to '1'.
 
 IR-visible record literals are already folded by the IR optimizer

diff --git a/pslua.cabal b/pslua.cabal
@@ -192,6 +192,7 @@ test-suite spec
     Language.PureScript.Backend.Lua.Optimizer.Spec
     Language.PureScript.Backend.Lua.Printer.Spec
     Language.PureScript.Backend.Lua.Run.Spec
+    Language.PureScript.Backend.Lua.Spec
     Language.PureScript.Backend.Output.Spec
     Language.PureScript.PSString.Spec
     Test.Hspec.Expectations.Pretty

diff --git a/test/Language/PureScript/Backend/Lua/Optimizer/Spec.hs b/test/Language/PureScript/Backend/Lua/Optimizer/Spec.hs
@@ -6,40 +6,15 @@ import Language.PureScript.Backend.Lua.Name (name)
 import Language.PureScript.Backend.Lua.Optimizer
   ( foldFieldProjectionThroughScopeCall
   , reduceTableDefinitionAccessor
-  , removeScopeWhenInsideEmptyFunction
   , rewriteExpWithRule
   )
-import Language.PureScript.Backend.Lua.Types (ParamF (..))
 import Language.PureScript.Backend.Lua.Types qualified as Lua
 import Test.Hspec (Spec, describe, it)
 import Test.Hspec.Expectations.Pretty (assertEqual)
 import Text.Pretty.Simple (pShow)
 
 spec ∷ Spec
 spec = describe "Lua AST Optimizer" do
-  describe "optimizes expressions" do
-    it "removes scope when inside an empty function" do
-      let original ∷ Lua.Exp =
-            Lua.functionDef
-              [ParamNamed [name|a|]]
-              [ Lua.return
-                  ( Lua.functionDef
-                      [ParamNamed [name|b|]]
-                      [Lua.return (Lua.scope [Lua.return (Lua.varName [name|c|])])]
-                  )
-              ]
-          expected ∷ Lua.Exp =
-            Lua.functionDef
-              [ParamNamed [name|a|]]
-              [ Lua.return
-                  ( Lua.functionDef
-                      [ParamNamed [name|b|]]
-                      [Lua.return (Lua.varName [name|c|])]
-                  )
-              ]
-      assertEqual (toString $ pShow original) expected $
-        rewriteExpWithRule removeScopeWhenInsideEmptyFunction original
-
   describe "reduceTableDefinitionAccessor" do
     it "folds a field access into an unambiguous name-value definition" do
       let original ∷ Lua.Exp =

diff --git a/test/Language/PureScript/Backend/Lua/Spec.hs b/test/Language/PureScript/Backend/Lua/Spec.hs
@@ -0,0 +1,84 @@
+module Language.PureScript.Backend.Lua.Spec where
+
+import Control.Monad.Oops (Variant)
+import Control.Monad.Trans.Except (ExceptT, runExceptT)
+import Data.Tagged (Tagged (..))
+import Data.Text qualified as Text
+import Language.PureScript.Backend.IR qualified as IR
+import Language.PureScript.Backend.IR.Linker (UberModule (..))
+import Language.PureScript.Backend.Lua qualified as Lua
+import Language.PureScript.Backend.Lua.Printer qualified as Printer
+import Language.PureScript.Backend.Lua.Types qualified as Lua.Types
+import Language.PureScript.Backend.Types (AppOrModule (AsModule))
+import Path.IO (getCurrentDir)
+import Prettyprinter (defaultLayoutOptions, layoutPretty)
+import Prettyprinter.Render.Text (renderStrict)
+import Test.Hspec (Spec, describe, expectationFailure, it, shouldSatisfy)
+
+spec ∷ Spec
+spec = describe "Lua.fromUberModule" do
+  it "does not wrap Abs-over-Let body in a scope IIFE" do
+    rendered ← compileExportedExpr absWithLetBody
+    rendered `shouldSatisfy` (not . Text.isInfixOf "(function()")
+
+  it "does not wrap Abs-over-IfThenElse body in a scope IIFE" do
+    rendered ← compileExportedExpr absWithIfBody
+    rendered `shouldSatisfy` (not . Text.isInfixOf "(function()")
+
+compileExportedExpr ∷ IR.Exp → IO Text
+compileExportedExpr expr = do
+  foreignPath ← Tagged <$> getCurrentDir
+  let
+    moduleName = IR.ModuleName "Test.AbsScopeIife"
+    uberModule =
+      UberModule
+        { uberModuleBindings = []
+        , uberModuleForeigns = []
+        , uberModuleExports = [(IR.Name "value", expr)]
+        }
+  result ←
+    runExceptT
+      ( Lua.fromUberModule
+          foreignPath
+          (Tagged False)
+          (AsModule moduleName)
+          uberModule
+          ∷ ExceptT (Variant '[Lua.Error]) IO Lua.Types.Chunk
+      )
+  case result of
+    Left _err → expectationFailure "Lua.fromUberModule failed" >> pure ""
+    Right chunk →
+      pure . renderStrict $
+        layoutPretty defaultLayoutOptions (Printer.printLuaChunk chunk)
+
+absWithLetBody ∷ IR.Exp
+absWithLetBody =
+  IR.Abs
+    IR.noAnn
+    (IR.ParamNamed IR.noAnn (IR.Name "x"))
+    ( IR.Let
+        IR.noAnn
+        ( IR.Standalone
+            ( IR.noAnn
+            , IR.Name "y"
+            , IR.App
+                IR.noAnn
+                (IR.Ref IR.noAnn (IR.Local (IR.Name "f")))
+                (IR.Ref IR.noAnn (IR.Local (IR.Name "x")))
+            )
+            :| []
+        )
+        (IR.Ref IR.noAnn (IR.Local (IR.Name "y")))
+    )
+
+absWithIfBody ∷ IR.Exp
+absWithIfBody =
+  IR.Abs
+    IR.noAnn
+    (IR.ParamNamed IR.noAnn (IR.Name "x"))
+    ( IR.IfThenElse
+        IR.noAnn
+        (IR.Ref IR.noAnn (IR.Local (IR.Name "p")))
+        (IR.Ref IR.noAnn (IR.Local (IR.Name "x")))
+        (IR.LiteralInt IR.noAnn 0)
+    )
diff --git a/test/Main.hs b/test/Main.hs
@@ -17,6 +17,7 @@ import Language.PureScript.Backend.Lua.NestingCheck.Spec qualified as NestingChe
 import Language.PureScript.Backend.Lua.Optimizer.Spec qualified as LuaOptimizer
 import Language.PureScript.Backend.Lua.Printer.Spec qualified as Printer
 import Language.PureScript.Backend.Lua.Run.Spec qualified as Run
+import Language.PureScript.Backend.Lua.Spec qualified as Lua
 import Language.PureScript.Backend.Output.Spec qualified as Output
 import Language.PureScript.PSString.Spec qualified as PSString
 import Test.Hspec (hspec)
@@ -34,6 +35,7 @@ main = hspec do
   IRPass.spec
   IRUniquify.spec
   LuaOptimizer.spec
+  Lua.spec
   Printer.spec
   Run.spec
   LuaLinkerForeign.spec