Prevent removal of inlined mutable vars from optimized AST (#6333)

* Don't remove inlined mutable vars * Added tests for inlined mutable vars
dotnet · Apr 11, 2019 · 9564307 · 9564307
1 parent 4394ee7
commit 9564307
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Showing 2 changed files with 22 additions and 3 deletions.
diff --git a/src/fsharp/symbols/Exprs.fs b/src/fsharp/symbols/Exprs.fs
@@ -852,15 +852,15 @@ module FSharpExprConvert =
             None, env.BindIsInstVal bind.Var (ty, e)
 
         // Remove let <compilerGeneratedVar> = <var> from quotation tree
-        | Expr.Val _ when bind.Var.IsCompilerGenerated -> 
+        | Expr.Val _ when bind.Var.IsCompilerGenerated && (not bind.Var.IsMutable) -> 
             None, env.BindSubstVal bind.Var bind.Expr
 
         // Remove let <compilerGeneratedVar> = () from quotation tree
-        | Expr.Const(Const.Unit, _, _) when bind.Var.IsCompilerGenerated -> 
+        | Expr.Const(Const.Unit, _, _) when bind.Var.IsCompilerGenerated && (not bind.Var.IsMutable) -> 
             None, env.BindSubstVal bind.Var bind.Expr
 
         // Remove let unionCase = ... from quotation tree
-        | Expr.Op(TOp.UnionCaseProof _, _, [e], _) -> 
+        | Expr.Op(TOp.UnionCaseProof _, _, [e], _) when (not bind.Var.IsMutable) -> 
             None, env.BindSubstVal bind.Var e
 
         | _ ->

diff --git a/tests/service/ExprTests.fs b/tests/service/ExprTests.fs
@@ -563,6 +563,17 @@ let testHashUIntPtr (x:unativeint) = hash x
 let testHashString (x:string) = hash x
 let testTypeOf (x:'T) = typeof<'T>
 
+let inline mutableVar x =
+    if x > 0 then
+        let mutable acc = x
+        acc <- x
+
+let inline mutableConst () =
+    let mutable acc = ()
+    acc <- ()
+
+let testMutableVar = mutableVar 1
+let testMutableConst = mutableConst ()
     """
 
     File.WriteAllText(fileName2, fileSource2)
@@ -753,6 +764,10 @@ let ``Test Unoptimized Declarations Project1`` () =
         "let testHashUIntPtr(x) = Operators.Hash<Microsoft.FSharp.Core.unativeint> (x) @ (14,37--14,43)";
         "let testHashString(x) = Operators.Hash<Microsoft.FSharp.Core.string> (x) @ (16,32--16,38)";
         "let testTypeOf(x) = Operators.TypeOf<'T> () @ (17,24--17,30)";
+        "let mutableVar(x) = (if Operators.op_GreaterThan<Microsoft.FSharp.Core.int> (x,0) then let mutable acc: Microsoft.FSharp.Core.int = x in acc <- x else ()) @ (20,4--22,16)";
+        "let mutableConst(unitVar0) = let mutable acc: Microsoft.FSharp.Core.unit = () in acc <- () @ (25,16--25,19)";
+        "let testMutableVar = N.mutableVar (1) @ (28,21--28,33)";
+        "let testMutableConst = N.mutableConst (()) @ (29,23--29,38)";
       ]
 
     printDeclarations None (List.ofSeq file1.Declarations) 
@@ -893,6 +908,10 @@ let ``Test Optimized Declarations Project1`` () =
         "let testHashUIntPtr(x) = Operators.op_BitwiseAnd<Microsoft.FSharp.Core.int> (Operators.ToInt32<Microsoft.FSharp.Core.uint64> (Operators.ToUInt64<Microsoft.FSharp.Core.unativeint> (x)),2147483647) @ (14,37--14,43)";
         "let testHashString(x) = (if Operators.op_Equality<Microsoft.FSharp.Core.string> (x,dflt) then 0 else Operators.Hash<Microsoft.FSharp.Core.string> (x)) @ (16,32--16,38)";
         "let testTypeOf(x) = Operators.TypeOf<'T> () @ (17,24--17,30)";
+        "let mutableVar(x) = (if Operators.op_GreaterThan<Microsoft.FSharp.Core.int> (x,0) then let mutable acc: Microsoft.FSharp.Core.int = x in acc <- x else ()) @ (20,4--22,16)";
+        "let mutableConst(unitVar0) = let mutable acc: Microsoft.FSharp.Core.unit = () in acc <- () @ (25,16--25,19)";
+        "let testMutableVar = let x: Microsoft.FSharp.Core.int = 1 in (if Operators.op_GreaterThan<Microsoft.FSharp.Core.int> (x,0) then let mutable acc: Microsoft.FSharp.Core.int = x in acc <- x else ()) @ (28,21--28,33)";
+        "let testMutableConst = let mutable acc: Microsoft.FSharp.Core.unit = () in acc <- () @ (29,23--29,38)";
       ]
 
     // printFSharpDecls "" file2.Declarations |> Seq.iter (printfn "%s")