Validate exception names for illegal characters using same mechanism as types/modules

.gitignore

@@ -132,6 +132,7 @@ micro.exe
 positive.exe
 /tests/FSharp.Compiler.ComponentTests/FSharpChecker/StandardError.txt
 /tests/FSharp.Compiler.ComponentTests/FSharpChecker/StandardOutput.txt
+/tests/FSharp.Compiler.ComponentTests/TestResults/
 
 # ilverify baseline result files
 *.bsl.actual

docs/release-notes/.Language/preview.md

@@ -9,6 +9,7 @@
 * Fix parsing errors using anonymous records and units of measures ([PR #18543](https://github.com/dotnet/fsharp/pull/18543))
 * Scoped Nowarn: added the #warnon compiler directive ([Language suggestion #278](https://github.com/fsharp/fslang-suggestions/issues/278), [RFC FS-1146 PR](https://github.com/fsharp/fslang-design/pull/782), [PR #18049](https://github.com/dotnet/fsharp/pull/18049))
 * Allow `let!` and `use!` type annotations without requiring parentheses. ([PR #18508](https://github.com/dotnet/fsharp/pull/18508))
+* Exception names are now validated for illegal characters using the same mechanism as types/modules/namespaces ([Issue #18763](https://github.com/dotnet/fsharp/issues/18763))
 
 ### Fixed
 

src/Compiler/Checking/CheckDeclarations.fs

@@ -2406,6 +2406,7 @@ module TcExceptionDeclarations =
     let TcExnDefnCore_Phase1A g cenv env parent (SynExceptionDefnRepr(Attributes synAttrs, SynUnionCase(ident= SynIdent(id,_)), _, xmlDoc, vis, m)) =
         let attrs = TcAttributes cenv env AttributeTargets.ExnDecl synAttrs
         if not (String.isLeadingIdentifierCharacterUpperCase id.idText) then errorR(NotUpperCaseConstructor id.idRange)
+        CheckNamespaceModuleOrTypeName g id
         let vis, cpath = ComputeAccessAndCompPath g env None m vis None parent
         let vis = TcRecdUnionAndEnumDeclarations.CombineReprAccess parent vis
         CheckForDuplicateConcreteType env (id.idText + "Exception") id.idRange

tests/FSharp.Compiler.ComponentTests/CompilerDirectives/NonStringArgs.fs

@@ -90,7 +90,7 @@ module NonStringArgs =
 #nowarn 20 FS1104 "3391" "FS3221"
 
 module Exception =
-    exception ``Crazy@name.p`` of string
+    exception ``Crazy@name`` of string
 
 module Decimal =
     type T1 = { a : decimal }
@@ -118,7 +118,7 @@ module DoBinding =
                 (Error 3350, Line 2, Col 9, Line 2, Col 11, "Feature '# directives with non-quoted string arguments' is not available in F# 8.0. Please use language version 9.0 or greater.")
                 (Error 3350, Line 2, Col 12, Line 2, Col 18, "Feature '# directives with non-quoted string arguments' is not available in F# 8.0. Please use language version 9.0 or greater.")
                 (Warning 203, Line 2, Col 26, Line 2, Col 34, "Invalid warning number 'FS3221'")
-                (Warning 1104, Line 5, Col 15, Line 5, Col 31, "Identifiers containing '@' are reserved for use in F# code generation")
+                (Warning 1104, Line 5, Col 15, Line 5, Col 29, "Identifiers containing '@' are reserved for use in F# code generation")
                 ]
         else
             compileResult

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters01.fsx

@@ -0,0 +1,8 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My.Exception``     // err: contains '.'
+exception ``My+Exception``     // err: contains '+'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters02.fsx

@@ -0,0 +1,8 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My$Exception``     // err: contains '$'
+exception ``My&Exception``     // err: contains '&'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters03.fsx

@@ -0,0 +1,8 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My[Exception``     // err: contains '['
+exception ``My]Exception``     // err: contains ']'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters04.fsx

@@ -0,0 +1,8 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My/Exception``     // err: contains '/'
+exception ``My\Exception``     // err: contains '\'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters05.fsx

@@ -0,0 +1,8 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My*Exception``     // err: contains '*'
+exception ``My"Exception``     // err: contains '"'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/E_IllegalCharacters06.fsx

@@ -0,0 +1,7 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Exception names must not contain illegal characters
+
+#light
+
+exception ``My`Exception`` // err: contains '`'

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/ExceptionDefinitions.fs

@@ -267,6 +267,7 @@ module ExceptionDefinition =
         |> withDiagnostics [
             (Warning 1104, Line 8, Col 11, Line 8, Col 27, "Identifiers containing '@' are reserved for use in F# code generation")
             (Warning 1104, Line 10, Col 16, Line 10, Col 41, "Identifiers containing '@' are reserved for use in F# code generation")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
             (Error 39, Line 10, Col 16, Line 10, Col 41, "The type '[email protected]' is not defined. Maybe you want one of the following:\r\n   [email protected]")
         ]
 
@@ -385,3 +386,84 @@ module ExceptionDefinition =
         |> withOptions ["--warnaserror+"; "--nowarn:988"]
         |> compileExeAndRun
         |> shouldSucceed
+
+    // Test cases for illegal characters in exception names
+    // SOURCE=E_IllegalCharacters01.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters01.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters01.fsx"|])>]
+    let``E_IllegalCharacters01_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=E_IllegalCharacters02.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters02.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters02.fsx"|])>]
+    let``E_IllegalCharacters02_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=E_IllegalCharacters03.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters03.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters03.fsx"|])>]
+    let``E_IllegalCharacters03_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=E_IllegalCharacters04.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters04.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters04.fsx"|])>]
+    let``E_IllegalCharacters04_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=E_IllegalCharacters05.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters05.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters05.fsx"|])>]
+    let``E_IllegalCharacters05_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+            (Error 883, Line 8, Col 11, Line 8, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=E_IllegalCharacters06.fsx                   SCFLAGS="--test:ErrorRanges"        # E_IllegalCharacters06.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_IllegalCharacters06.fsx"|])>]
+    let``E_IllegalCharacters06_fsx`` compilation =
+        compilation
+        |> asExe
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 883, Line 7, Col 11, Line 7, Col 27, "Invalid namespace, module, type or union case name")
+        ]
+
+    // SOURCE=LegalExceptionNames.fsx                                                          # LegalExceptionNames.fsx
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"LegalExceptionNames.fsx"|])>]
+    let``LegalExceptionNames_fsx`` compilation =
+        compilation
+        |> asExe
+        |> withOptions ["--warnaserror+"; "--nowarn:988"]
+        |> compileExeAndRun
+        |> shouldSucceed

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/ExceptionDefinitions/LegalExceptionNames.fsx

@@ -0,0 +1,20 @@
+// #Regression #Conformance #TypesAndModules #Exceptions 
+// Exception types
+// Legal exception names should compile successfully
+
+#light
+
+exception MyException
+exception MyOtherException
+exception Exception123
+exception ExceptionWithLongName
+exception A
+
+let test() =
+    try
+        raise (MyException)
+    with
+    | MyException -> printfn "Caught MyException"
+    | _ -> printfn "Caught other"
+
+let () = test()