PR for trials related to FS-1043

src/fsharp/ConstraintSolver.fs

@@ -310,9 +310,12 @@ let rec occursCheck g un ty =
 /// During code gen we run with permitWeakResolution on, but we only apply it where one of the argument types for the built-in constraint resolution is
 /// a variable type.
 type PermitWeakResolution = 
-    | Yes of codegen: bool
+    | YesAtInlineGeneralization
+    | YesAtResolution
+    | YesAtCodeGen
     | No
-    member x.Permit = match x with Yes _ -> true | No -> false
+    member x.PerformWeakBuiltInResolution = match x with YesAtInlineGeneralization | YesAtResolution | YesAtCodeGen -> true | No -> false
+    member x.PerformWeakOverloadResolution = match x with YesAtResolution -> true | YesAtInlineGeneralization | YesAtCodeGen  | No -> false
 
 let rec isNativeIntegerTy g ty =
     typeEquivAux EraseMeasures g g.nativeint_ty ty || 
@@ -410,7 +413,8 @@ let IsBinaryOpArgTypePair p1 p2 permitWeakResolution minfos g ty1 ty2 =
 
     // During regular canonicalization (weak resolution) we don't do any check on the other type at all - we 
     // ignore the possibility that method overloads may resolve the constraint
-    | PermitWeakResolution.Yes false ->
+    | PermitWeakResolution.YesAtInlineGeneralization
+    | PermitWeakResolution.YesAtResolution -> 
         // weak resolution lets the other type be a variable type
         isTyparTy g ty2 || 
         // If the other type is not a variable type, it is nominal,
@@ -419,7 +423,7 @@ let IsBinaryOpArgTypePair p1 p2 permitWeakResolution minfos g ty1 ty2 =
         typeEquivAux EraseMeasures g ty1 ty2
 
     // During codegen we only apply a builtin resolution if both the types are correct
-    | PermitWeakResolution.Yes true ->
+    | PermitWeakResolution.YesAtCodeGen ->
         p2 ty2 &&
         // All built-in rules only apply in cases where left and right operator types are equal (after
         // erasing units)
@@ -1603,7 +1607,7 @@ and SolveMemberConstraint (csenv: ConstraintSolverEnv) ignoreUnresolvedOverload
                   // If there's nothing left to learn then raise the errors.
                   // Note: we should likely call MemberConstraintIsReadyForResolution here when permitWeakResolution=false but for stability
                   // reasons we use the more restrictive isNil frees.
-                  if (permitWeakResolution.Permit && MemberConstraintIsReadyForWeakResolution csenv traitInfo) || isNil frees then 
+                  if (permitWeakResolution.PerformWeakOverloadResolution && MemberConstraintIsReadyForWeakResolution csenv traitInfo) || isNil frees then 
                       do! errors  
                   else
                       do! AddMemberConstraint csenv ndeep m2 trace traitInfo support frees
@@ -1709,7 +1713,7 @@ and GetRelevantExtensionMethodsForTrait m (amap: Import.ImportMap) (traitInfo: T
 /// That is, don't perform resolution if more nominal information may influence the set of available overloads 
 and GetRelevantMethodsForTrait (csenv: ConstraintSolverEnv) (permitWeakResolution: PermitWeakResolution) nm (TTrait(tys, _, memFlags, argtys, rty, soln, extSlns, ad) as traitInfo) : MethInfo list =
     let results = 
-        if permitWeakResolution.Permit || MemberConstraintSupportIsReadyForDeterminingOverloads csenv traitInfo then
+        if permitWeakResolution.PerformWeakOverloadResolution || MemberConstraintSupportIsReadyForDeterminingOverloads csenv traitInfo then
             let m = csenv.m
             let minfos = 
                 match memFlags.MemberKind with
@@ -1816,8 +1820,9 @@ and SolveRelevantMemberConstraintsForTypar (csenv:ConstraintSolverEnv) ndeep (pe
         let csenv = { csenv with m = m2 }
         SolveMemberConstraint csenv true permitWeakResolution (ndeep+1) m2 trace traitInfo)
 
-and CanonicalizeRelevantMemberConstraints (csenv: ConstraintSolverEnv) ndeep trace tps =
-    SolveRelevantMemberConstraints csenv ndeep (PermitWeakResolution.Yes false) trace tps
+and CanonicalizeRelevantMemberConstraints (csenv: ConstraintSolverEnv) ndeep trace tps isInline =
+    let permitWeakResolution = (if isInline then PermitWeakResolution.YesAtInlineGeneralization else PermitWeakResolution.YesAtResolution)
+    SolveRelevantMemberConstraints csenv ndeep permitWeakResolution trace tps
 
 and AddMemberConstraint (csenv: ConstraintSolverEnv) ndeep m2 (trace: OptionalTrace) traitInfo support (frees: Typar list) =
     let g = csenv.g
@@ -3080,7 +3085,7 @@ let CodegenWitnessThatTypeSupportsTraitConstraint tcVal g amap m (traitInfo: Tra
 
     let csenv = MakeConstraintSolverEnv ContextInfo.NoContext css m (DisplayEnv.Empty g)
 
-    let! _res = SolveMemberConstraint csenv true (PermitWeakResolution.Yes true) 0 m NoTrace traitInfo
+    let! _res = SolveMemberConstraint csenv true PermitWeakResolution.YesAtCodeGen 0 m NoTrace traitInfo
 
     let sln = 
         match traitInfo.Solution with 
@@ -3225,11 +3230,11 @@ let CheckDeclaredTypars denv css m typars1 typars2 =
             ErrorD (ErrorFromAddingConstraint(denv, res, m)))
     |> RaiseOperationResult
 
-let CanonicalizePartialInferenceProblem css denv m tps =
+let CanonicalizePartialInferenceProblem css denv m tps isInline =
     // Canonicalize constraints prior to generalization 
     let csenv = MakeConstraintSolverEnv ContextInfo.NoContext css m denv
     TryD_IgnoreAbortForFailedOverloadResolution
-        (fun () -> CanonicalizeRelevantMemberConstraints csenv 0 NoTrace tps)
+        (fun () -> CanonicalizeRelevantMemberConstraints csenv 0 NoTrace tps isInline)
         (fun res -> ErrorD (ErrorFromAddingConstraint(denv, res, m))) 
     |> RaiseOperationResult
 

src/fsharp/ConstraintSolver.fsi

@@ -190,4 +190,4 @@ val ChooseTyparSolutionAndSolve: ConstraintSolverState -> DisplayEnv -> Typar ->
 
 val IsApplicableMethApprox: TcGlobals -> ImportMap -> range -> MethInfo -> TType -> bool
 
-val CanonicalizePartialInferenceProblem:  ConstraintSolverState -> DisplayEnv -> range -> Typars -> unit
+val CanonicalizePartialInferenceProblem:  ConstraintSolverState -> DisplayEnv -> range -> Typars -> bool -> unit

src/fsharp/TypeChecker.fs

@@ -6772,7 +6772,7 @@ and TcObjectExprBinding cenv (env: TcEnv) implty tpenv (absSlotInfo, bind) =
             | _ -> 
                 declaredTypars
         // Canonicalize constraints prior to generalization 
-        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv m declaredTypars
+        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv m declaredTypars true
 
         let freeInEnv = GeneralizationHelpers.ComputeUngeneralizableTypars env
 
@@ -9862,7 +9862,7 @@ and TcLookupThen cenv overallTy env tpenv mObjExpr objExpr objExprTy longId dela
 
     // Canonicalize inference problem prior to '.' lookup on variable types 
     if isTyparTy cenv.g objExprTy then 
-        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css env.DisplayEnv mExprAndLongId (freeInTypeLeftToRight cenv.g false objExprTy)
+        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css env.DisplayEnv mExprAndLongId (freeInTypeLeftToRight cenv.g false objExprTy) false
 
     let item, mItem, rest, afterResolution = ResolveExprDotLongIdentAndComputeRange cenv.tcSink cenv.nameResolver mExprAndLongId ad env.NameEnv objExprTy longId findFlag false
     let mExprAndItem = unionRanges mObjExpr mItem
@@ -10410,8 +10410,8 @@ and TcMethodApplication
         // about the possible target of the call. 
         if not uniquelyResolved then 
             ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv mItem
-                 (//freeInTypeLeftToRight cenv.g false returnTy @
-                  (unnamedCurriedCallerArgs |> List.collectSquared (fun callerArg -> freeInTypeLeftToRight cenv.g false callerArg.Type)))
+                 (unnamedCurriedCallerArgs |> List.collectSquared (fun callerArg -> freeInTypeLeftToRight cenv.g false callerArg.Type))
+                 false
 
         let result, errors = ResolveOverloadingForCall denv cenv.css mMethExpr methodName 0 None callerArgCounts ad postArgumentTypeCheckingCalledMethGroup true (Some returnTy) 
 
@@ -11371,12 +11371,17 @@ and TcLetBinding cenv isUse env containerInfo declKind tpenv (synBinds, synBinds
 
     // Canonicalize constraints prior to generalization 
     let denv = env.DisplayEnv
+    let isInline = 
+        (checkedBinds |> List.forall (fun tbinfo -> 
+            let (CheckedBindingInfo(inl, _, _, _, _, _, _, _, _, _, _, _, _, _)) = tbinfo
+            (inl = ValInline.PseudoVal)))
     ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv synBindsRange
         (checkedBinds |> List.collect (fun tbinfo -> 
             let (CheckedBindingInfo(_, _, _, _, flex, _, _, _, tauTy, _, _, _, _, _)) = tbinfo
             let (ExplicitTyparInfo(_, declaredTypars, _)) = flex
             let maxInferredTypars = (freeInTypeLeftToRight cenv.g false tauTy)
             declaredTypars @ maxInferredTypars))
+        isInline
 
     let lazyFreeInEnv = lazy (GeneralizationHelpers.ComputeUngeneralizableTypars env)
 
@@ -12246,7 +12251,11 @@ and TcIncrementalLetRecGeneralization cenv scopem
             else
 
                 let supportForBindings = newGeneralizableBindings |> List.collect (TcLetrecComputeSupportForBinding cenv)
-                ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv scopem supportForBindings 
+                let isInline = 
+                    (newGeneralizableBindings |> List.forall (fun tbinfo -> 
+                        let (CheckedBindingInfo(inl, _, _, _, _, _, _, _, _, _, _, _, _, _)) = tbinfo.CheckedBinding
+                        (inl = ValInline.PseudoVal)))
+                ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denv scopem supportForBindings isInline 
 
                 let generalizedTyparsL = newGeneralizableBindings |> List.map (TcLetrecComputeAndGeneralizeGenericTyparsForBinding cenv denv freeInEnv) 
 
@@ -17751,7 +17760,7 @@ let ApplyDefaults cenv g denvAtEnd m mexpr extraAttribs =
     try
         let unsolved = FSharp.Compiler.FindUnsolved.UnsolvedTyparsOfModuleDef g cenv.amap denvAtEnd (mexpr, extraAttribs)
 
-        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denvAtEnd m unsolved
+        ConstraintSolver.CanonicalizePartialInferenceProblem cenv.css denvAtEnd m unsolved false
 
         // The priority order comes from the order of declaration of the defaults in FSharp.Core.
         for priority = 10 downto 0 do