Fix find all references for F# exceptions (#18565)

Author: majocha

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

@@ -1,4 +1,5 @@
 ### Fixed
 
 * Allow `let!` and `use!` type annotations without requiring parentheses ([PR #18508](https://github.com/dotnet/fsharp/pull/18508))
+* Fix find all references for F# exceptions ([PR #18565](https://github.com/dotnet/fsharp/pull/18565))
 * Shorthand lambda: fix completion for chained calls and analysis for unfinished expression ([PR #18560](https://github.com/dotnet/fsharp/pull/18560))

src/Compiler/Symbols/Symbols.fs

@@ -360,7 +360,8 @@ type FSharpEntity(cenv: SymbolEnv, entity: EntityRef, tyargs: TType list) =
     inherit FSharpSymbol(cenv, 
                          (fun () -> 
                               checkEntityIsResolved entity
-                              if entity.IsModuleOrNamespace then Item.ModuleOrNamespaces [entity] 
+                              if entity.IsModuleOrNamespace then Item.ModuleOrNamespaces [entity]
+                              elif entity.IsFSharpException then Item.ExnCase entity
                               else Item.UnqualifiedType [entity]), 
                          (fun _this thisCcu2 ad -> 
                              checkForCrossProjectAccessibility cenv.g.ilg (thisCcu2, ad) (cenv.thisCcu, getApproxFSharpAccessibilityOfEntity entity)) 

tests/FSharp.Compiler.ComponentTests/FSharpChecker/FindReferences.fs

@@ -265,6 +265,33 @@ val myFunc2: param: int -> int
                 ])
             }
 
+module Exceptions =
+    let project() = SyntheticProject.Create(
+        { sourceFile "First" [] with ExtraSource = "exception MyException of string" },
+        { sourceFile "Second" [] with ExtraSource = """
+open ModuleFirst
+let foo x = raise (MyException "foo")""" })
+
+    [<Fact>]
+    let ``We find exception from definition`` () =
+        project().Workflow {
+            placeCursor "First" 6 21 "exception MyException of string" ["MyException"]
+            findAllReferences (expectToFind [
+                "FileFirst.fs", 6, 10, 21
+                "FileSecond.fs", 8, 19, 30
+            ])
+        }
+
+    [<Fact>]
+    let ``We find exception from usage`` () =
+        project().Workflow {
+            placeCursor "Second" 8 30 "raise (MyException \"foo\")" ["MyException"]
+            findAllReferences (expectToFind [
+                "FileFirst.fs", 6, 10, 21
+                "FileSecond.fs", 8, 19, 30
+            ])
+        }
+
 module Attributes =
 
     let project() = SyntheticProject.Create(

tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_netstandard2.0.bsl

@@ -40,7 +40,7 @@
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000082][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x0000008B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000094][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$Symbols+fullName@2495-1::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000015][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$Symbols+fullName@2496-1::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000015][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CreateILModule+MainModuleBuilder::ConvertProductVersionToILVersionInfo(string)][offset 0x00000011][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.StaticLinking+TypeForwarding::followTypeForwardForILTypeRef([FSharp.Compiler.Service]FSharp.Compiler.AbstractIL.IL+ILTypeRef)][offset 0x00000010][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CompilerOptions::getCompilerOption([FSharp.Compiler.Service]FSharp.Compiler.CompilerOptions+CompilerOption, [FSharp.Core]Microsoft.FSharp.Core.FSharpOption`1<int32>)][offset 0x000000E6][found Char] Unexpected type on the stack.

tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_netstandard2.0.bsl

@@ -39,7 +39,7 @@
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000064][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x0000006D][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000076][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$Symbols+fullName@2495-3::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000030][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$Symbols+fullName@2496-3::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000030][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Driver+ProcessCommandLineFlags@286-1::Invoke(string)][offset 0x0000000B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Driver+ProcessCommandLineFlags@286-1::Invoke(string)][offset 0x00000014][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CreateILModule+MainModuleBuilder::ConvertProductVersionToILVersionInfo(string)][offset 0x00000010][found Char] Unexpected type on the stack.