Fix a broken debug assertion that kicked in whenever building Fsharp.Core (#14435)

* Fix a broken debug assertion that kicked in whenever building Fsharp.Core in Debug
* HasMethodImplNoInliningAttribute unification

src/Compiler/Checking/CheckExpressions.fs

@@ -1210,6 +1210,12 @@ let CheckRequiredProperties (g:TcGlobals) (env: TcEnv) (cenv: TcFileState) (minf
                 let details = NicePrint.multiLineStringOfPropInfos g cenv.amap mMethExpr env.DisplayEnv missingProps
                 errorR(Error(FSComp.SR.tcMissingRequiredMembers details, mMethExpr))
 
+let private HasMethodImplNoInliningAttribute g attrs = 
+            match TryFindFSharpAttribute g g.attrib_MethodImplAttribute attrs with
+            // NO_INLINING = 8
+            | Some (Attrib(_, _, [ AttribInt32Arg flags ], _, _, _, _)) -> (flags &&& 0x8) <> 0x0
+            | _ -> false
+
 let MakeAndPublishVal (cenv: cenv) env (altActualParent, inSig, declKind, valRecInfo, vscheme, attrs, xmlDoc, konst, isGeneratedEventVal) =
 
     let g = cenv.g
@@ -1258,16 +1264,10 @@ let MakeAndPublishVal (cenv: cenv) env (altActualParent, inSig, declKind, valRec
               errorR(Error(FSComp.SR.tcDllImportStubsCannotBeInlined(), m)) 
             ValInline.Never 
         else 
-            let implflags = 
-                match TryFindFSharpAttribute g g.attrib_MethodImplAttribute attrs with
-                | Some (Attrib(_, _, [ AttribInt32Arg flags ], _, _, _, _)) -> flags
-                | _ -> 0x0
-            // MethodImplOptions.NoInlining = 0x8
-            let NO_INLINING = 0x8
-            if (implflags &&& NO_INLINING) <> 0x0 then
-                ValInline.Never
-            else
-                inlineFlag
+            if HasMethodImplNoInliningAttribute g attrs 
+            then ValInline.Never 
+            else inlineFlag             
+        
 
     // CompiledName not allowed on virtual/abstract/override members
     let compiledNameAttrib = TryFindFSharpStringAttribute g g.attrib_CompiledNameAttribute attrs
@@ -2205,26 +2205,32 @@ module GeneralizationHelpers =
 // ComputeInlineFlag
 //-------------------------------------------------------------------------
 
-let ComputeInlineFlag (memFlagsOption: SynMemberFlags option) isInline isMutable hasNoCompilerInliningAttribute m =
-    let inlineFlag =
-        let isCtorOrAbstractSlot =
-            match memFlagsOption with
-            | None -> false
-            | Some x -> (x.MemberKind = SynMemberKind.Constructor) || x.IsDispatchSlot || x.IsOverrideOrExplicitImpl
+let ComputeInlineFlag (memFlagsOption: SynMemberFlags option) isInline isMutable g attrs m =
+    let hasNoCompilerInliningAttribute() = HasFSharpAttribute g g.attrib_NoCompilerInliningAttribute attrs  
+    let isCtorOrAbstractSlot() =
+        match memFlagsOption with
+        | None -> false
+        | Some x -> (x.MemberKind = SynMemberKind.Constructor) || x.IsDispatchSlot || x.IsOverrideOrExplicitImpl
 
+    let inlineFlag, reportIncorrectInlineKeywordUsage =
         // Mutable values may never be inlined
         // Constructors may never be inlined
         // Calls to virtual/abstract slots may never be inlined
-        // Values marked with NoCompilerInliningAttribute may never be inlined
-        if isMutable || isCtorOrAbstractSlot || hasNoCompilerInliningAttribute then
-            ValInline.Never 
+        // Values marked with NoCompilerInliningAttribute or [<MethodImpl(MethodImplOptions.NoInlining)>] may never be inlined
+        if isMutable || isCtorOrAbstractSlot() || hasNoCompilerInliningAttribute() then
+            ValInline.Never, errorR
+        elif HasMethodImplNoInliningAttribute g attrs then
+            ValInline.Never, 
+                if g.langVersion.SupportsFeature LanguageFeature.WarningWhenInliningMethodImplNoInlineMarkedFunction
+                then warning
+                else ignore
         elif isInline then
-            ValInline.Always 
+            ValInline.Always, ignore
         else
-            ValInline.Optional
+            ValInline.Optional, ignore
 
     if isInline && (inlineFlag <> ValInline.Always) then 
-        errorR(Error(FSComp.SR.tcThisValueMayNotBeInlined(), m))
+        reportIncorrectInlineKeywordUsage (Error(FSComp.SR.tcThisValueMayNotBeInlined(), m))
 
     inlineFlag
 
@@ -10278,10 +10284,8 @@ and TcNormalizedBinding declKind (cenv: cenv) env tpenv overallTy safeThisValOpt
                 SynValData(valMf, SynValInfo(args, SynArgInfo({Attributes=rotRetSynAttrs; Range=mHead} :: attrs, opt, retId)), valId)
             retAttribs, valAttribs, valSynData
 
-        let isVolatile = HasFSharpAttribute g g.attrib_VolatileFieldAttribute valAttribs
-        let hasNoCompilerInliningAttribute = HasFSharpAttribute g g.attrib_NoCompilerInliningAttribute valAttribs
-
-        let inlineFlag = ComputeInlineFlag memberFlagsOpt isInline isMutable hasNoCompilerInliningAttribute mBinding
+        let isVolatile = HasFSharpAttribute g g.attrib_VolatileFieldAttribute valAttribs     
+        let inlineFlag = ComputeInlineFlag memberFlagsOpt isInline isMutable g valAttribs mBinding
 
         let argAttribs = 
             spatsL |> List.map (SynInfo.InferSynArgInfoFromSimplePats >> List.map (SynInfo.AttribsOfArgData >> TcAttrs AttributeTargets.Parameter false))
@@ -11414,10 +11418,9 @@ and AnalyzeAndMakeAndPublishRecursiveValue
     let bindingAttribs = TcAttributes cenv env attrTgt bindingSynAttribs
 
     // Allocate the type inference variable for the inferred type
-    let ty = NewInferenceType g
-    let hasNoCompilerInliningAttribute = HasFSharpAttribute g g.attrib_NoCompilerInliningAttribute bindingAttribs
+    let ty = NewInferenceType g  
 
-    let inlineFlag = ComputeInlineFlag memberFlagsOpt isInline isMutable hasNoCompilerInliningAttribute mBinding
+    let inlineFlag = ComputeInlineFlag memberFlagsOpt isInline isMutable g bindingAttribs mBinding
 
     if isMutable then errorR(Error(FSComp.SR.tcOnlyRecordFieldsAndSimpleLetCanBeMutable(), mBinding))
 
@@ -12033,7 +12036,6 @@ let TcAndPublishValSpec (cenv: cenv, env, containerInfo: ContainerInfo, declKind
 
     let attrs = TcAttributes cenv env attrTgt synAttrs
     let newOk = if canInferTypars then NewTyparsOK else NoNewTypars
-    let hasNoCompilerInliningAttribute = HasFSharpAttribute g g.attrib_NoCompilerInliningAttribute attrs
 
     let valinfos, tpenv = TcValSpec cenv env declKind newOk containerInfo memFlagsOpt None tpenv synValSig attrs
     let denv = env.DisplayEnv
@@ -12042,7 +12044,7 @@ let TcAndPublishValSpec (cenv: cenv, env, containerInfo: ContainerInfo, declKind
 
         let (ValSpecResult (altActualParent, memberInfoOpt, id, enclosingDeclaredTypars, declaredTypars, ty, prelimValReprInfo, declKind)) = valSpecResult
 
-        let inlineFlag = ComputeInlineFlag (memberInfoOpt |> Option.map (fun (PrelimMemberInfo(memberInfo, _, _)) -> memberInfo.MemberFlags)) isInline mutableFlag hasNoCompilerInliningAttribute m
+        let inlineFlag = ComputeInlineFlag (memberInfoOpt |> Option.map (fun (PrelimMemberInfo(memberInfo, _, _)) -> memberInfo.MemberFlags)) isInline mutableFlag g attrs m
 
         let freeInType = freeInTypeLeftToRight g false ty
 

src/Compiler/FSComp.txt

@@ -1558,6 +1558,7 @@ featureLowercaseDUWhenRequireQualifiedAccess,"Allow lowercase DU when RequireQua
 featureMatchNotAllowedForUnionCaseWithNoData,"Pattern match discard is not allowed for union case that takes no data."
 featureCSharpExtensionAttributeNotRequired,"Allow implicit Extension attribute on declaring types, modules"
 featureErrorForNonVirtualMembersOverrides,"Raises errors for non-virtual members overrides"
+featureWarningWhenInliningMethodImplNoInlineMarkedFunction,"Raises warnings when 'let inline ... =' is used together with [<MethodImpl(MethodImplOptions.NoInlining)>] attribute. Function is not getting inlined."
 featureArithmeticInLiterals,"Allow arithmetic and logical operations in literals"
 3353,fsiInvalidDirective,"Invalid directive '#%s %s'"
 3354,tcNotAFunctionButIndexerNamedIndexingNotYetEnabled,"This value supports indexing, e.g. '%s.[index]'. The syntax '%s[index]' requires /langversion:preview. See https://aka.ms/fsharp-index-notation."

src/Compiler/Facilities/LanguageFeatures.fs

@@ -57,6 +57,7 @@ type LanguageFeature =
     | MatchNotAllowedForUnionCaseWithNoData
     | CSharpExtensionAttributeNotRequired
     | ErrorForNonVirtualMembersOverrides
+    | WarningWhenInliningMethodImplNoInlineMarkedFunction
     | EscapeDotnetFormattableStrings
     | ArithmeticInLiterals
 
@@ -132,6 +133,7 @@ type LanguageVersion(versionText) =
                 LanguageFeature.MatchNotAllowedForUnionCaseWithNoData, previewVersion
                 LanguageFeature.CSharpExtensionAttributeNotRequired, previewVersion
                 LanguageFeature.ErrorForNonVirtualMembersOverrides, previewVersion
+                LanguageFeature.WarningWhenInliningMethodImplNoInlineMarkedFunction, previewVersion
                 LanguageFeature.EscapeDotnetFormattableStrings, previewVersion
                 LanguageFeature.ArithmeticInLiterals, previewVersion
 
@@ -242,8 +244,9 @@ type LanguageVersion(versionText) =
         | LanguageFeature.InterfacesWithAbstractStaticMembers -> FSComp.SR.featureInterfacesWithAbstractStaticMembers ()
         | LanguageFeature.SelfTypeConstraints -> FSComp.SR.featureSelfTypeConstraints ()
         | LanguageFeature.MatchNotAllowedForUnionCaseWithNoData -> FSComp.SR.featureMatchNotAllowedForUnionCaseWithNoData ()
-        | LanguageFeature.CSharpExtensionAttributeNotRequired -> FSComp.SR.featureCSharpExtensionAttributeNotRequired ()
-        | LanguageFeature.ErrorForNonVirtualMembersOverrides -> FSComp.SR.featureErrorForNonVirtualMembersOverrides ()
+        | LanguageFeature.CSharpExtensionAttributeNotRequired -> FSComp.SR.featureCSharpExtensionAttributeNotRequired  ()
+        | LanguageFeature.ErrorForNonVirtualMembersOverrides -> FSComp.SR.featureErrorForNonVirtualMembersOverrides  ()
+        | LanguageFeature.WarningWhenInliningMethodImplNoInlineMarkedFunction -> FSComp.SR.featureWarningWhenInliningMethodImplNoInlineMarkedFunction ()
         | LanguageFeature.EscapeDotnetFormattableStrings -> FSComp.SR.featureEscapeBracesInFormattableString ()
         | LanguageFeature.ArithmeticInLiterals -> FSComp.SR.featureArithmeticInLiterals ()
 

src/Compiler/Facilities/LanguageFeatures.fsi

@@ -47,6 +47,7 @@ type LanguageFeature =
     | MatchNotAllowedForUnionCaseWithNoData
     | CSharpExtensionAttributeNotRequired
     | ErrorForNonVirtualMembersOverrides
+    | WarningWhenInliningMethodImplNoInlineMarkedFunction
     | EscapeDotnetFormattableStrings
     | ArithmeticInLiterals
 

src/Compiler/xlf/FSComp.txt.cs.xlf

@@ -337,6 +337,11 @@
         <target state="translated">reprezentace struktury aktivních vzorů</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">zástupný znak ve smyčce for</target>

src/Compiler/xlf/FSComp.txt.de.xlf

@@ -337,6 +337,11 @@
         <target state="translated">Strukturdarstellung für aktive Muster</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">Platzhalter in for-Schleife</target>

src/Compiler/xlf/FSComp.txt.es.xlf

@@ -337,6 +337,11 @@
         <target state="translated">representación de struct para modelos activos</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">carácter comodín en bucle for</target>

src/Compiler/xlf/FSComp.txt.fr.xlf

@@ -337,6 +337,11 @@
         <target state="translated">représentation de structure pour les modèles actifs</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">caractère générique dans une boucle for</target>

src/Compiler/xlf/FSComp.txt.it.xlf

@@ -337,6 +337,11 @@
         <target state="translated">rappresentazione struct per criteri attivi</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">carattere jolly nel ciclo for</target>

src/Compiler/xlf/FSComp.txt.ja.xlf

@@ -337,6 +337,11 @@
         <target state="translated">アクティブなパターンの構造体表現</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">for ループのワイルド カード</target>

src/Compiler/xlf/FSComp.txt.ko.xlf

@@ -337,6 +337,11 @@
         <target state="translated">활성 패턴에 대한 구조체 표현</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">for 루프의 와일드카드</target>

src/Compiler/xlf/FSComp.txt.pl.xlf

@@ -337,6 +337,11 @@
         <target state="translated">reprezentacja struktury aktywnych wzorców</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">symbol wieloznaczny w pętli for</target>

src/Compiler/xlf/FSComp.txt.pt-BR.xlf

@@ -337,6 +337,11 @@
         <target state="translated">representação estrutural para padrões ativos</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">curinga para loop</target>

src/Compiler/xlf/FSComp.txt.ru.xlf

@@ -337,6 +337,11 @@
         <target state="translated">представление структуры для активных шаблонов</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">подстановочный знак в цикле for</target>

src/Compiler/xlf/FSComp.txt.tr.xlf

@@ -337,6 +337,11 @@
         <target state="translated">etkin desenler için yapı gösterimi</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">for döngüsünde joker karakter</target>

src/Compiler/xlf/FSComp.txt.zh-Hans.xlf

@@ -337,6 +337,11 @@
         <target state="translated">活动模式的结构表示形式</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">for 循环中的通配符</target>

src/Compiler/xlf/FSComp.txt.zh-Hant.xlf

@@ -337,6 +337,11 @@
         <target state="translated">現用模式的結構表示法</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
+        <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
+        <target state="new">Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureWildCardInForLoop">
         <source>wild card in for loop</source>
         <target state="translated">for 迴圈中的萬用字元</target>

tests/FSharp.Compiler.ComponentTests/EmittedIL/MethodImplAttribute/MethodImplAttribute.NoInlining_InlineKeyword.fs

+module M
+[<System.Runtime.CompilerServices.MethodImplAttribute(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)>]
+let inline getUnit (f : unit -> unit) = f()
\ No newline at end of file

tests/FSharp.Compiler.ComponentTests/EmittedIL/MethodImplAttribute/MethodImplAttribute.fs

@@ -33,6 +33,20 @@ module MethodImplAttribute =
     let ``NoInlining_fs`` compilation =
         compilation
         |> verifyCompilation
+     
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"MethodImplAttribute.NoInlining_InlineKeyword.fs"|])>]
+    let ``NoInlining_fs with inline keyword => should warn in preview version`` compilation =
+        compilation
+        |> withLangVersionPreview
+        |> typecheck
+        |> withSingleDiagnostic (Warning 3151, Line 2, Col 1, Line 3, Col 38, "This member, function or value declaration may not be declared 'inline'")
+    
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"MethodImplAttribute.NoInlining_InlineKeyword.fs"|])>]
+    let ``NoInlining_fs with inline keyword => should not warn in F# 7 or older`` compilation =
+        compilation
+        |> withLangVersion70
+        |> typecheck
+        |> withDiagnostics  []       
 
     // SOURCE=MethodImplAttribute.AggressiveInlining.fs SCFLAGS="-a -g --optimize-" COMPILE_ONLY=1 POSTCMD="..\\CompareIL.cmd MethodImplAttribute.AggressiveInlining.dll"	# MethodImplAttribute.AggressiveInlining.fs
     [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"MethodImplAttribute.AggressiveInlining.fs"|])>]

tests/FSharp.Test.Utilities/Compiler.fs

@@ -391,6 +391,9 @@ module rec Compiler =
     let withLangVersion70 (cUnit: CompilationUnit) : CompilationUnit =
         withOptionsHelper [ "--langversion:7.0" ] "withLangVersion70 is only supported on F#" cUnit
 
+    let withLangVersion80 (cUnit: CompilationUnit) : CompilationUnit =
+        withOptionsHelper [ "--langversion:8.0" ] "withLangVersion80 is only supported on F#" cUnit
+
     let withLangVersionPreview (cUnit: CompilationUnit) : CompilationUnit =
         withOptionsHelper [ "--langversion:preview" ] "withLangVersionPreview is only supported on F#" cUnit