Moving ElseBranchHasWrongTypeTests over to NUnit (#7104)

Author: forki

tests/fsharp/Compiler/ErrorMessages/ElseBranchHasWrongTypeTests.fs

@@ -0,0 +1,176 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace FSharp.Compiler.UnitTests
+
+open NUnit.Framework
+open FSharp.Compiler.SourceCodeServices
+
+[<TestFixture>]
+module ``Else branch has wrong type`` =
+
+    [<Test>]
+    let ``Else branch is int while if branch is string``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let y =
+    if test > 10 then "test"
+    else 123
+            """
+            FSharpErrorSeverity.Error
+            1
+            (5, 10, 5, 13)
+            "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'string'. This branch returns a value of type 'int'."
+
+    [<Test>]
+    let ``Else branch is a function that returns int while if branch is string``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let f x = test
+let y =
+    if test > 10 then "test"
+    else f 10
+            """
+            FSharpErrorSeverity.Error
+            1
+            (6, 10, 6, 14)
+            "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'string'. This branch returns a value of type 'int'."
+
+
+    [<Test>]
+    let ``Else branch is a sequence of expressions that returns int while if branch is string``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let f x = x + 4
+
+let y =
+    if true then
+        ""
+    else
+        "" |> ignore
+        (f 5)
+            """
+            FSharpErrorSeverity.Error
+            1
+            (9, 10, 9, 13)
+            "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'string'. This branch returns a value of type 'int'."
+
+
+    [<Test>]
+    let ``Else branch is a longer sequence of expressions that returns int while if branch is string``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let f x = x + 4
+
+let y =
+    if true then
+        ""
+    else
+        "" |> ignore
+        let z = f 4
+        let a = 3 * z
+        (f a)
+            """
+            FSharpErrorSeverity.Error
+            1
+            (11, 10, 11, 13)
+            "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'string'. This branch returns a value of type 'int'."
+
+
+    [<Test>]
+    let ``Else branch context doesn't propagate into function application``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let f x : string = x
+let y =
+    if test > 10 then "test"
+    else
+        f 123
+            """
+            FSharpErrorSeverity.Error
+            1
+            (7, 11, 7, 14)
+            "This expression was expected to have type\n    'string'    \nbut here has type\n    'int'    "
+
+    [<Test>]
+    let ``Else branch context doesn't propagate into function application even if not last expr``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let f x = printfn "%s" x
+let y =
+    if test > 10 then "test"
+    else
+        f 123
+        "test"
+            """
+            FSharpErrorSeverity.Error
+            1
+            (7, 11, 7, 14)
+            "This expression was expected to have type\n    'string'    \nbut here has type\n    'int'    "
+
+    [<Test>]
+    let ``Else branch context doesn't propagate into for loop``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let list = [1..10]
+let y =
+    if test > 10 then "test"
+    else
+        for (x:string) in list do
+            printfn "%s" x
+
+        "test"
+            """
+            FSharpErrorSeverity.Error
+            1
+            (7, 14, 7, 22)
+            "This expression was expected to have type\n    'int'    \nbut here has type\n    'string'    "
+
+    [<Test>]
+    let ``Else branch context doesn't propagate to lines before last line``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let test = 100
+let list = [1..10]
+let y =
+    if test > 10 then "test"
+    else
+        printfn "%s" 1
+
+        "test"
+            """
+            FSharpErrorSeverity.Error
+            1
+            (7, 22, 7, 23)
+            "This expression was expected to have type\n    'string'    \nbut here has type\n    'int'    "
+
+    [<Test>]
+    let ``Else branch should not have wrong context type``() =
+        CompilerAssert.TypeCheckWithErrors
+            """
+let x = 1
+let y : bool =
+    if x = 2 then "A"
+    else "B"
+            """
+            [| FSharpErrorSeverity.Error, 1, (4, 19, 4, 22), "The 'if' expression needs to have type 'bool' to satisfy context type requirements. It currently has type 'string'."
+               FSharpErrorSeverity.Error, 1, (5, 10, 5, 13), "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'bool'. This branch returns a value of type 'string'." |]
+
+
+    [<Test>]
+    let ``Else branch has wrong type in nested if``() =
+        CompilerAssert.TypeCheckWithErrors
+            """
+let x = 1
+if x = 1 then true
+else
+    if x = 2 then "A"
+    else "B"
+            """
+            [| FSharpErrorSeverity.Error, 1, (5, 19, 5, 22), "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'bool'. This branch returns a value of type 'string'."
+               FSharpErrorSeverity.Error, 1, (6, 10, 6, 13), "All branches of an 'if' expression must return values of the same type as the first branch, which here is 'bool'. This branch returns a value of type 'string'."
+               FSharpErrorSeverity.Warning, 20, (3, 1, 6, 13), "The result of this expression has type 'bool' 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'." |]

tests/fsharp/FSharpSuite.Tests.fsproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
@@ -32,6 +32,7 @@
     <Compile Include="tests.fs" />
     <Compile Include="Compiler\ILChecker.fs" />
     <Compile Include="Compiler\CompilerAssert.fs" />
+    <Compile Include="Compiler\ErrorMessages\ElseBranchHasWrongTypeTests.fs" />
     <Compile Include="Compiler\SourceTextTests.fs" />
     <Compile Include="Compiler\Language\AnonRecordTests.fs" />
     <Compile Include="Compiler\Language\SpanOptimizationTests.fs" />