Fix [Experiment]

src/Compiler/Driver/CompilerDiagnostics.fs

@@ -822,6 +822,12 @@ type Exception with
                 if ty1 <> ty2 + tpcs then
                     os.AppendString(ErrorFromAddingTypeEquation2E().Format ty1 ty2 tpcs)
 
+            let e =
+                match e with
+                | ConstraintSolverTypesNotInEqualityRelation(env, ty1b, ty2b, m, m2, contextInfo) when typeEquiv g ty2 ty2b ->
+                    ConstraintSolverTypesNotInEqualityRelation(env, ty2b, ty1b, m, m2, contextInfo)
+                | _ -> e
+
             e.Output(os, suggestNames)
 
         | ErrorFromApplyingDefault(_, denv, _, defaultType, e, _) ->

src/Compiler/Symbols/FSharpDiagnostic.fs

@@ -176,6 +176,7 @@ type FSharpDiagnostic(m: range, severity: FSharpDiagnosticSeverity, message: str
             | Some symbolEnv ->
 
             match diagnostic.Exception with
+            | ErrorFromAddingConstraint(displayEnv, ConstraintSolverTypesNotInEqualityRelation(_, actualType, expectedType, _, _, contextInfo), _)
             | ErrorFromAddingTypeEquation(_, displayEnv, expectedType, actualType, ConstraintSolverTupleDiffLengths(contextInfo = contextInfo), _)
             | ErrorsFromAddingSubsumptionConstraint(_, displayEnv, expectedType, actualType, _, contextInfo, _) ->
                let context = DiagnosticContextInfo.From(contextInfo)
@@ -187,6 +188,8 @@ type FSharpDiagnostic(m: range, severity: FSharpDiagnosticSeverity, message: str
                        ty1, ty2
                    elif not (typeEquiv g ty1 ty2) then
                        ty1, ty2
+                   elif typeEquiv g ty1 ty2b then
+                       ty1b, ty2b
                    else ty2b, ty1b
 
                let context = DiagnosticContextInfo.From(contextInfo)

tests/FSharp.Compiler.ComponentTests/Conformance/Types/RecordTypes/RecordTypes.fs

@@ -116,7 +116,7 @@ module RecordTypes =
             (Warning 464, Line 15, Col 22, Line 15, Col 28, "This code is less generic than indicated by its annotations. A unit-of-measure specified using '_' has been determined to be '1', i.e. dimensionless. Consider making the code generic, or removing the use of '_'.")
             (Warning 464, Line 15, Col 35, Line 15, Col 42, "This code is less generic than indicated by its annotations. A unit-of-measure specified using '_' has been determined to be '1', i.e. dimensionless. Consider making the code generic, or removing the use of '_'.")
             (Error 5, Line 17, Col 1, Line 17, Col 5, "This field is not mutable")
-            (Error 1, Line 17, Col 16, Line 17, Col 22, "The type 'decimal<Kg>' does not match the type 'float<Kg>'")
+            (Error 1, Line 17, Col 16, Line 17, Col 22, "The type 'float<Kg>' does not match the type 'decimal<Kg>'")
             (Error 5, Line 18, Col 1, Line 18, Col 5, "This field is not mutable")
             (Error 1, Line 18, Col 16, Line 18, Col 21, "This expression was expected to have type\n    'float'    \nbut here has type\n    'decimal'    ")
         ]

tests/FSharp.Compiler.ComponentTests/Conformance/Types/TypeConstraints/IWSAMsAndSRTPs/IWSAMsAndSRTPsTests.fs

@@ -1145,7 +1145,7 @@ module StaticAbstractBug =
         |> compile
         |> shouldFail
         |> withDiagnostics [
-            (Error 1, Line 14, Col 41, Line 14, Col 42, "The type 'bool' does not match the type 'int'")
+            (Error 1, Line 14, Col 41, Line 14, Col 42, "The type 'int' does not match the type 'bool'")
             (Error 1, Line 16, Col 32, Line 16, Col 33, "This expression was expected to have type
     'bool'    
 but here has type

tests/FSharp.Compiler.ComponentTests/ErrorMessages/ExtendedDiagnosticDataTests.fs

@@ -12,14 +12,15 @@ let inline checkDiagnosticData
     (check: 'a -> unit)
     (checkResults: 'b when 'b: (member Diagnostics: FSharpDiagnostic[])) =
     match checkResults.Diagnostics |> Array.tryFind (fun d -> d.ErrorNumber = diagnosticNumber) with
-    | None -> failwith "Expected diagnostic not found"
+    | None -> failwith $"Expected diagnostic (number {diagnosticNumber}) not found"
     | Some diagnostic ->
 
     Assert.Equal(message, diagnostic.Message)
     match diagnostic.ExtendedData with
     | Some(:? 'a as data) -> check data
     | _ -> failwith "Expected diagnostic extended data not found"
 
+    checkResults
 
 [<Fact>]
 let ``TypeMismatchDiagnosticExtendedData 01`` () =
@@ -187,6 +188,46 @@ let f2 (x: inref<'T>) = f1 &x
         Assert.Equal("outref<'T>", typeMismatch.ExpectedType.Format(displayContext))
         Assert.Equal("inref<'T>", typeMismatch.ActualType.Format(displayContext)))
 
+[<Fact>]
+let ``TypeMismatchDiagnosticExtendedData 11`` () =
+    FSharp """
+type T() =
+    static member P1 = T.P2 + 1
+    static member P2 = ""
+"""
+    |> typecheckResults
+    // static member P1 = T.P2 ->+<- 1
+    |> checkDiagnosticData
+       (43, "The type 'int' does not match the type 'string'")
+       (fun (typeMismatch: TypeMismatchDiagnosticExtendedData) ->
+            let displayContext = typeMismatch.DisplayContext
+            Assert.Equal(DiagnosticContextInfo.NoContext, typeMismatch.ContextInfo)
+            Assert.Equal("string", typeMismatch.ExpectedType.Format(displayContext))
+            Assert.Equal("int", typeMismatch.ActualType.Format(displayContext)))
+
+    // static member P2 = ->""<-
+    |> checkDiagnosticData
+        (1, "The type 'string' does not match the type 'int'")
+        (fun (typeMismatch: TypeMismatchDiagnosticExtendedData) ->
+             let displayContext = typeMismatch.DisplayContext
+             Assert.Equal(DiagnosticContextInfo.NoContext, typeMismatch.ContextInfo)
+             Assert.Equal("int", typeMismatch.ExpectedType.Format(displayContext))
+             Assert.Equal("string", typeMismatch.ActualType.Format(displayContext)))
+
+[<Fact>]
+let ``TypeMismatchDiagnosticExtendedData 12`` () =
+    FSharp """
+let x: string = 1 + 1
+"""
+    |> typecheckResults
+    |> checkDiagnosticData
+       (1, "The type 'int' does not match the type 'string'")
+       (fun (typeMismatch: TypeMismatchDiagnosticExtendedData) ->
+            let displayContext = typeMismatch.DisplayContext
+            Assert.Equal(DiagnosticContextInfo.NoContext, typeMismatch.ContextInfo)
+            Assert.Equal("string", typeMismatch.ExpectedType.Format(displayContext))
+            Assert.Equal("int", typeMismatch.ActualType.Format(displayContext)))
+
 [<Theory>]
 [<InlineData true>]
 [<InlineData false>]