Fix: eta reduction

Author: Unisay

.hspec-failures

@@ -0,0 +1 @@
+FailureReport {failureReportSeed = 1246204243, failureReportMaxSuccess = 100, failureReportMaxSize = 100, failureReportMaxDiscardRatio = 10, failureReportPaths = []}

lib/Language/PureScript/Backend/IR/Optimizer.hs

@@ -279,13 +279,12 @@ etaReduce ∷ RewriteRule Ann
 etaReduce =
   pure . \case
     Abs _ (ParamNamed _ param) (App _ m (Ref _ (Local param') 0))
-      | param == param' →
+      | param == param' && countFreeRef (Local param) m == 0 →
           Rewritten Recurse m
     _ → NoChange
 
 betaReduceUnusedParams ∷ RewriteRule Ann
-betaReduceUnusedParams =
-  pure . \case
+betaReduceUnusedParams = pure . \case
     App _ (Abs _ (ParamUnused _) body) _arg →
       Rewritten Recurse body
     _ → NoChange

test/ps/golden/Golden/Inline/Test.purs

@@ -1,4 +1,9 @@
-module Golden.Inline.Test where
+module Golden.Inline.Test
+  ( main
+  , Mu
+  , runMu
+  , iMu
+  ) where
 
 main :: Int
 main =
@@ -7,3 +12,11 @@ main =
   in let  y :: forall b. b -> Int
           y _ = 2
       in x y
+
+newtype Mu a = MkMu (Mu a -> a)
+
+runMu :: forall a. Mu a -> a
+runMu mu@(MkMu f) = f mu
+
+iMu :: Mu Int
+iMu = MkMu runMu

test/ps/output/Golden.Inline.Test/corefn.json

@@ -1 +1 @@
-{"builtWith":"0.15.15","comments":[],"decls":[{"annotation":{"meta":null,"sourceSpan":{"end":[3,12],"start":[3,1]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[9,13],"start":[5,3]}},"binds":[{"annotation":{"meta":null,"sourceSpan":{"end":[5,30],"start":[5,7]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[5,30],"start":[5,7]}},"argument":"v","body":{"annotation":{"meta":null,"sourceSpan":{"end":[6,14],"start":[6,13]}},"type":"Literal","value":{"literalType":"IntLiteral","value":1}},"type":"Abs"},"identifier":"x"}],"expression":{"annotation":{"meta":null,"sourceSpan":{"end":[9,13],"start":[7,6]}},"binds":[{"annotation":{"meta":null,"sourceSpan":{"end":[7,34],"start":[7,11]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[7,34],"start":[7,11]}},"argument":"v","body":{"annotation":{"meta":null,"sourceSpan":{"end":[8,18],"start":[8,17]}},"type":"Literal","value":{"literalType":"IntLiteral","value":2}},"type":"Abs"},"identifier":"y"}],"expression":{"abstraction":{"annotation":{"meta":null,"sourceSpan":{"end":[9,11],"start":[9,10]}},"type":"Var","value":{"identifier":"x","sourcePos":[5,7]}},"annotation":{"meta":null,"sourceSpan":{"end":[9,13],"start":[9,10]}},"argument":{"annotation":{"meta":null,"sourceSpan":{"end":[9,13],"start":[9,12]}},"type":"Var","value":{"identifier":"y","sourcePos":[7,11]}},"type":"App"},"type":"Let"},"type":"Let"},"identifier":"main"}],"exports":["main"],"foreign":[],"imports":[{"annotation":{"meta":null,"sourceSpan":{"end":[9,13],"start":[1,1]}},"moduleName":["Prim"]}],"moduleName":["Golden","Inline","Test"],"modulePath":"golden/Golden/Inline/Test.purs","reExports":{},"sourceSpan":{"end":[9,13],"start":[1,1]}}
+{"builtWith":"0.15.15","comments":[],"decls":[{"annotation":{"meta":null,"sourceSpan":{"end":[16,32],"start":[16,1]}},"bindType":"NonRec","expression":{"annotation":{"meta":{"metaType":"IsNewtype"},"sourceSpan":{"end":[16,32],"start":[16,1]}},"argument":"x","body":{"annotation":{"meta":null,"sourceSpan":{"end":[16,32],"start":[16,1]}},"type":"Var","value":{"identifier":"x","sourcePos":[0,0]}},"type":"Abs"},"identifier":"MkMu"},{"annotation":{"meta":null,"sourceSpan":{"end":[18,29],"start":[18,1]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[18,29],"start":[18,1]}},"argument":"v","body":{"annotation":{"meta":null,"sourceSpan":{"end":[18,29],"start":[18,1]}},"caseAlternatives":[{"binders":[{"annotation":{"meta":null,"sourceSpan":{"end":[19,18],"start":[19,7]}},"binder":{"annotation":{"meta":{"metaType":"IsNewtype"},"sourceSpan":{"end":[19,17],"start":[19,11]}},"binderType":"ConstructorBinder","binders":[{"annotation":{"meta":null,"sourceSpan":{"end":[19,17],"start":[19,16]}},"binderType":"VarBinder","identifier":"f"}],"constructorName":{"identifier":"MkMu","moduleName":["Golden","Inline","Test"]},"typeName":{"identifier":"Mu","moduleName":["Golden","Inline","Test"]}},"binderType":"NamedBinder","identifier":"mu"}],"expression":{"abstraction":{"annotation":{"meta":null,"sourceSpan":{"end":[19,22],"start":[19,21]}},"type":"Var","value":{"identifier":"f","sourcePos":[19,16]}},"annotation":{"meta":null,"sourceSpan":{"end":[19,25],"start":[19,21]}},"argument":{"annotation":{"meta":null,"sourceSpan":{"end":[19,25],"start":[19,23]}},"type":"Var","value":{"identifier":"mu","sourcePos":[19,7]}},"type":"App"},"isGuarded":false}],"caseExpressions":[{"annotation":{"meta":null,"sourceSpan":{"end":[19,25],"start":[19,1]}},"type":"Var","value":{"identifier":"v","sourcePos":[0,0]}}],"type":"Case"},"type":"Abs"},"identifier":"runMu"},{"annotation":{"meta":null,"sourceSpan":{"end":[8,12],"start":[8,1]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[14,13],"start":[10,3]}},"binds":[{"annotation":{"meta":null,"sourceSpan":{"end":[10,30],"start":[10,7]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[10,30],"start":[10,7]}},"argument":"v","body":{"annotation":{"meta":null,"sourceSpan":{"end":[11,14],"start":[11,13]}},"type":"Literal","value":{"literalType":"IntLiteral","value":1}},"type":"Abs"},"identifier":"x"}],"expression":{"annotation":{"meta":null,"sourceSpan":{"end":[14,13],"start":[12,6]}},"binds":[{"annotation":{"meta":null,"sourceSpan":{"end":[12,34],"start":[12,11]}},"bindType":"NonRec","expression":{"annotation":{"meta":null,"sourceSpan":{"end":[12,34],"start":[12,11]}},"argument":"v","body":{"annotation":{"meta":null,"sourceSpan":{"end":[13,18],"start":[13,17]}},"type":"Literal","value":{"literalType":"IntLiteral","value":2}},"type":"Abs"},"identifier":"y"}],"expression":{"abstraction":{"annotation":{"meta":null,"sourceSpan":{"end":[14,11],"start":[14,10]}},"type":"Var","value":{"identifier":"x","sourcePos":[10,7]}},"annotation":{"meta":null,"sourceSpan":{"end":[14,13],"start":[14,10]}},"argument":{"annotation":{"meta":null,"sourceSpan":{"end":[14,13],"start":[14,12]}},"type":"Var","value":{"identifier":"y","sourcePos":[12,11]}},"type":"App"},"type":"Let"},"type":"Let"},"identifier":"main"},{"annotation":{"meta":null,"sourceSpan":{"end":[21,14],"start":[21,1]}},"bindType":"NonRec","expression":{"abstraction":{"annotation":{"meta":{"metaType":"IsNewtype"},"sourceSpan":{"end":[22,11],"start":[22,7]}},"type":"Var","value":{"identifier":"MkMu","moduleName":["Golden","Inline","Test"]}},"annotation":{"meta":null,"sourceSpan":{"end":[22,17],"start":[22,7]}},"argument":{"annotation":{"meta":null,"sourceSpan":{"end":[22,17],"start":[22,12]}},"type":"Var","value":{"identifier":"runMu","moduleName":["Golden","Inline","Test"]}},"type":"App"},"identifier":"iMu"}],"exports":["main","runMu","iMu"],"foreign":[],"imports":[{"annotation":{"meta":null,"sourceSpan":{"end":[22,17],"start":[1,1]}},"moduleName":["Golden","Inline","Test"]},{"annotation":{"meta":null,"sourceSpan":{"end":[22,17],"start":[1,1]}},"moduleName":["Prim"]}],"moduleName":["Golden","Inline","Test"],"modulePath":"golden/Golden/Inline/Test.purs","reExports":{},"sourceSpan":{"end":[22,17],"start":[1,1]}}

test/ps/output/Golden.Inline.Test/golden.ir

@@ -1,4 +1,23 @@
 UberModule
-  { uberModuleBindings = [], uberModuleForeigns = [], uberModuleExports =
-    [ ( Name "main", LiteralInt Nothing 1 ) ]
+  { uberModuleBindings =
+    [ Standalone
+      ( QName
+        { qnameModuleName = ModuleName "Golden.Inline.Test", qnameName = Name "runMu"
+        }, Abs Nothing
+        ( ParamNamed Nothing ( Name "v" ) )
+        ( App Nothing
+          ( Ref Nothing ( Local ( Name "v" ) ) 0 )
+          ( Ref Nothing ( Local ( Name "v" ) ) 0 )
+        )
+      )
+    ], uberModuleForeigns = [], uberModuleExports =
+    [
+      ( Name "main", LiteralInt Nothing 1 ),
+      ( Name "runMu", Ref Nothing
+        ( Imported ( ModuleName "Golden.Inline.Test" ) ( Name "runMu" ) ) 0
+      ),
+      ( Name "iMu", Ref Nothing
+        ( Imported ( ModuleName "Golden.Inline.Test" ) ( Name "runMu" ) ) 0
+      )
+    ]
   }

test/ps/output/Golden.Inline.Test/golden.lua

@@ -1 +1,7 @@
-return { main = 1 }
+local M = {}
+M.Golden_Inline_Test_runMu = function(v) return v(v) end
+return {
+  main = 1,
+  runMu = M.Golden_Inline_Test_runMu,
+  iMu = M.Golden_Inline_Test_runMu
+}