Type checker: use inner expr range in upcast constraints errors (#18850)

Author: auduchinok

docs/release-notes/.FSharp.Compiler.Service/10.0.100.md

@@ -24,6 +24,7 @@
 
 ### Changed
 * Use `errorR` instead of `error` in `CheckDeclarations.fs` when possible. ([PR #18645](https://github.com/dotnet/fsharp/pull/18645))
+* Type checker: use inner expr range in upcast constraints errors ([PR #18850](https://github.com/dotnet/fsharp/pull/18850))
 
 ### Breaking Changes
 

src/Compiler/Checking/Expressions/CheckExpressions.fs

@@ -3004,20 +3004,19 @@ let TcRuntimeTypeTest isCast isOperator (cenv: cenv) denv m tgtTy srcTy =
                 warning(Error(FSComp.SR.tcTypeTestLossy(NicePrint.minimalStringOfTypeWithNullness denv ety, NicePrint.minimalStringOfType denv (stripTyEqnsWrtErasure EraseAll g ety)), m))
 
 ///  Checks, warnings and constraint assertions for upcasts
-let TcStaticUpcast (cenv: cenv) denv m tgtTy srcTy =
+let TcStaticUpcast (cenv: cenv) denv mSourceExpr mUpcastExpr tgtTy srcTy =
     let g = cenv.g
     if isTyparTy g tgtTy then
         if not (destTyparTy g tgtTy).IsCompatFlex then
-            error(IndeterminateStaticCoercion(denv, srcTy, tgtTy, m))
-            //else warning(UpcastUnnecessary m)
+            error(IndeterminateStaticCoercion(denv, srcTy, tgtTy, mUpcastExpr))
 
     if isSealedTy g tgtTy && not (isTyparTy g tgtTy) then
-        warning(CoercionTargetSealed(denv, tgtTy, m))
+        warning(CoercionTargetSealed(denv, tgtTy, mUpcastExpr))
 
     if typeEquiv g srcTy tgtTy then
-        warning(UpcastUnnecessary m)
+        warning(UpcastUnnecessary mUpcastExpr)
 
-    AddCxTypeMustSubsumeType ContextInfo.NoContext denv cenv.css m NoTrace tgtTy srcTy
+    AddCxTypeMustSubsumeType ContextInfo.NoContext denv cenv.css mSourceExpr NoTrace tgtTy srcTy
 
 let BuildPossiblyConditionalMethodCall (cenv: cenv) env isMutable m isProp minfo valUseFlags minst objArgs args staticTyOpt =
 
@@ -6139,7 +6138,7 @@ and TcExprUpcast (cenv: cenv) overallTy env tpenv (synExpr, synInnerExpr, m) =
         | SynExpr.InferredUpcast _ ->
             overallTy.Commit, tpenv
         | _ -> failwith "upcast"
-    TcStaticUpcast cenv env.DisplayEnv m tgtTy srcTy
+    TcStaticUpcast cenv env.DisplayEnv synInnerExpr.Range m tgtTy srcTy
     let expr = mkCoerceExpr(innerExpr, tgtTy, m, srcTy)
     expr, tpenv
 

tests/FSharp.Compiler.ComponentTests/Conformance/Expressions/ControlFlowExpressions/Type-relatedExpressions/Type-relatedExpressions.fs

@@ -74,4 +74,16 @@ module TyperelatedExpressions =
             (Warning 20, Line 9, Col 1, Line 9, Col 22, "The result of this expression has type 'obj' and is implicitly ignored. Consider using 'ignore' to discard this value explicitly, e.g. 'expr |> ignore', or 'let' to bind the result to a name, e.g. 'let result = expr'.")
         ]
 
+    [<Fact>]
+    let ``Upcast 01`` () =
+        FSharp """
+module Module
 
+type A() =
+    class end
+
+not true :> A |> ignore
+"""
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [(Error 193, Line 7, Col 1, Line 7, Col 9, "Type constraint mismatch. The type \n    'bool'    \nis not compatible with type\n    'A'    \n")]

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

@@ -17,7 +17,7 @@ let c = orig :> Dictionary<obj,obj>
         """
         |> typecheck
         |> shouldFail
-        |> withSingleDiagnostic (Error 193, Line 5, Col 9, Line 5, Col 36,
+        |> withSingleDiagnostic (Error 193, Line 5, Col 9, Line 5, Col 13,
                                  "Type constraint mismatch. The type \n    'IDictionary<obj,obj>'    \nis not compatible with type\n    'Dictionary<obj,obj>'    \n")
 
     [<Fact>]

tests/fsharpqa/Source/Conformance/Expressions/Type-relatedExpressions/E_StaticCoercion_class_not_impl_iface.fsx

@@ -2,11 +2,11 @@
 // Negative tests on :>
 // Cast to an interface not implemented
 
-//<Expects id="FS0193" span="(25,12-25,20)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(25,19-25,20)" status="error">Type constraint mismatch\. The type</Expects>
 
-//<Expects id="FS0193" span="(26,12-26,18)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(26,12-26,13)" status="error">Type constraint mismatch\. The type</Expects>
 
-//<Expects id="FS0193" span="(27,12-27,18)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(27,12-27,13)" status="error">Type constraint mismatch\. The type</Expects>
 
 
 

tests/fsharpqa/Source/Conformance/Expressions/Type-relatedExpressions/E_StaticCoercion_class_not_subclass.fsx

@@ -2,11 +2,11 @@
 // Negative tests on :>
 // Cast to a class that is not parent
 
-//<Expects id="FS0193" span="(20,12-20,20)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(20,19-20,20)" status="error">Type constraint mismatch\. The type</Expects>
 
-//<Expects id="FS0193" span="(21,12-21,18)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(21,12-21,13)" status="error">Type constraint mismatch\. The type</Expects>
 
-//<Expects id="FS0193" span="(22,12-22,19)" status="error">Type constraint mismatch\. The type</Expects>
+//<Expects id="FS0193" span="(22,12-22,13)" status="error">Type constraint mismatch\. The type</Expects>