Attempt to make links from single identifier module names. (#16550)

* Add scenarios where parentheses are around module name.

* Address problem tighter to nameof usage.

* Restore missing commit and inline nameof ident check.

* Add release note entry.

Author: nojaf

docs/release-notes/.FSharp.Compiler.Service/8.0.300.md

@@ -1,6 +1,7 @@
 ### Fixed
 
 * Code generated files with > 64K methods and generated symbols crash when loaded. Use infered sequence points for debugging. ([Issue #16399](https://github.com/dotnet/fsharp/issues/16399), [#PR 16514](https://github.com/dotnet/fsharp/pull/16514))
+* `nameof Module` expressions and patterns are processed to link files in `--test:GraphBasedChecking`. ([PR #16550](https://github.com/dotnet/fsharp/pull/16550))
 
 ### Added
 

src/Compiler/Driver/GraphChecking/DependencyResolution.fs

@@ -1,7 +1,6 @@
 module internal FSharp.Compiler.GraphChecking.DependencyResolution
 
 open FSharp.Compiler.Syntax
-open Internal.Utilities.Library
 
 /// <summary>Find a path from a starting TrieNode and return the end node or None</summary>
 let queryTriePartial (trie: TrieNode) (path: LongIdentifier) : TrieNode option =
@@ -118,6 +117,20 @@ let rec processStateEntry (trie: TrieNode) (state: FileContentQueryState) (entry
             FoundDependencies = foundDependencies
         }
 
+    | ModuleName name ->
+        // We need to check if the module name is a hit in the Trie.
+        let state' =
+            let queryResult = queryTrie trie [ name ]
+            processIdentifier queryResult state
+
+        match state.OwnNamespace with
+        | None -> state'
+        | Some ns ->
+            // If there we currently have our own namespace,
+            // the combination of that namespace + module name should be checked as well.
+            let queryResult = queryTrieDual trie ns [ name ]
+            processIdentifier queryResult state'
+
 /// <summary>
 /// For a given file's content, collect all missing ("ghost") file dependencies that the core resolution algorithm didn't return,
 /// but are required to satisfy the type-checker.

src/Compiler/Driver/GraphChecking/FileContentMapping.fs

@@ -18,6 +18,11 @@ let longIdentToPath (skipLast: bool) (longId: LongIdent) : LongIdentifier =
 let synLongIdentToPath (skipLast: bool) (synLongIdent: SynLongIdent) =
     longIdentToPath skipLast synLongIdent.LongIdent
 
+/// In some rare cases we are interested in the name of a single Ident.
+/// For example `nameof ModuleName` in expressions or patterns.
+let visitIdentAsPotentialModuleName (moduleNameIdent: Ident) =
+    FileContentEntry.ModuleName moduleNameIdent.idText
+
 let visitSynLongIdent (lid: SynLongIdent) : FileContentEntry list = visitLongIdent lid.LongIdent
 
 let visitLongIdent (lid: LongIdent) =
@@ -302,9 +307,28 @@ let visitSynTypeConstraint (tc: SynTypeConstraint) : FileContentEntry list =
     | SynTypeConstraint.WhereTyparIsEnum(typeArgs = typeArgs) -> List.collect visitSynType typeArgs
     | SynTypeConstraint.WhereTyparIsDelegate(typeArgs = typeArgs) -> List.collect visitSynType typeArgs
 
+[<return: Struct>]
+let inline (|NameofIdent|_|) (ident: Ident) =
+    if ident.idText = "nameof" then ValueSome() else ValueNone
+
+/// Special case of `nameof Module` type of expression
+let (|NameofExpr|_|) (e: SynExpr) =
+    let rec stripParen (e: SynExpr) =
+        match e with
+        | SynExpr.Paren(expr = expr) -> stripParen expr
+        | _ -> e
+
+    match e with
+    | SynExpr.App(flag = ExprAtomicFlag.NonAtomic; isInfix = false; funcExpr = SynExpr.Ident NameofIdent; argExpr = moduleNameExpr) ->
+        match stripParen moduleNameExpr with
+        | SynExpr.Ident moduleNameIdent -> Some moduleNameIdent
+        | _ -> None
+    | _ -> None
+
 let visitSynExpr (e: SynExpr) : FileContentEntry list =
     let rec visit (e: SynExpr) (continuation: FileContentEntry list -> FileContentEntry list) : FileContentEntry list =
         match e with
+        | NameofExpr moduleNameIdent -> continuation [ visitIdentAsPotentialModuleName moduleNameIdent ]
         | SynExpr.Const _ -> continuation []
         | SynExpr.Paren(expr = expr) -> visit expr continuation
         | SynExpr.Quote(operator = operator; quotedExpr = quotedExpr) ->
@@ -389,7 +413,7 @@ let visitSynExpr (e: SynExpr) : FileContentEntry list =
         | SynExpr.IfThenElse(ifExpr = ifExpr; thenExpr = thenExpr; elseExpr = elseExpr) ->
             let continuations = List.map visit (ifExpr :: thenExpr :: Option.toList elseExpr)
             Continuation.concatenate continuations continuation
-        | SynExpr.Typar _ -> continuation []
+        | SynExpr.Typar _
         | SynExpr.Ident _ -> continuation []
         | SynExpr.LongIdent(longDotId = longDotId) -> continuation (visitSynLongIdent longDotId)
         | SynExpr.LongIdentSet(longDotId, expr, _) -> visit expr (fun nodes -> visitSynLongIdent longDotId @ nodes |> continuation)
@@ -517,9 +541,29 @@ let visitSynExpr (e: SynExpr) : FileContentEntry list =
 
     visit e id
 
+/// Special case of `| nameof Module ->` type of pattern
+let (|NameofPat|_|) (pat: SynPat) =
+    let rec stripPats p =
+        match p with
+        | SynPat.Paren(pat = pat) -> stripPats pat
+        | _ -> p
+
+    match pat with
+    | SynPat.LongIdent(longDotId = SynLongIdent(id = [ NameofIdent ]); typarDecls = None; argPats = SynArgPats.Pats [ moduleNamePat ]) ->
+        match stripPats moduleNamePat with
+        | SynPat.LongIdent(
+            longDotId = SynLongIdent.SynLongIdent(id = [ moduleNameIdent ]; dotRanges = []; trivia = [ None ])
+            extraId = None
+            typarDecls = None
+            argPats = SynArgPats.Pats []
+            accessibility = None) -> Some moduleNameIdent
+        | _ -> None
+    | _ -> None
+
 let visitPat (p: SynPat) : FileContentEntry list =
     let rec visit (p: SynPat) (continuation: FileContentEntry list -> FileContentEntry list) : FileContentEntry list =
         match p with
+        | NameofPat moduleNameIdent -> continuation [ visitIdentAsPotentialModuleName moduleNameIdent ]
         | SynPat.Paren(pat = pat) -> visit pat continuation
         | SynPat.Typed(pat = pat; targetType = t) -> visit pat (fun nodes -> nodes @ visitSynType t)
         | SynPat.Const _ -> continuation []

src/Compiler/Driver/GraphChecking/Types.fs

@@ -73,6 +73,9 @@ type internal FileContentEntry =
     /// Being explicit about nested modules allows for easier reasoning what namespaces (paths) are open.
     /// We can scope an `OpenStatement` to the everything that is happening inside the nested module.
     | NestedModule of name: string * nestedContent: FileContentEntry list
+    /// A single identifier that could be the name of a module.
+    /// Example use-case: `let x = nameof Foo` where `Foo` is a module.
+    | ModuleName of name: Identifier
 
 type internal FileContent =
     {

src/Compiler/Driver/GraphChecking/Types.fsi

@@ -67,6 +67,9 @@ type internal FileContentEntry =
     /// Being explicit about nested modules allows for easier reasoning what namespaces (paths) are open.
     /// For example we can limit the scope of an `OpenStatement` to symbols defined inside the nested module.
     | NestedModule of name: string * nestedContent: FileContentEntry list
+    /// A single identifier that could be the name of a module.
+    /// Example use-case: `let x = nameof Foo` where `Foo` is a module.
+    | ModuleName of name: Identifier
 
 /// File identifiers and its content extract for dependency resolution
 type internal FileContent =

tests/FSharp.Compiler.ComponentTests/TypeChecks/Graph/Scenarios.fs

@@ -800,4 +800,114 @@ printfn "Hello"
 """
                     Set.empty
             ]
+        scenario
+            "Nameof module with namespace"
+            [
+                sourceFile
+                    "A.fs"
+                    """
+namespace X.Y.Z
+
+module Foo =
+    let x = 2
+"""
+                    Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+namespace X.Y.Z
+
+module Point =
+    let y = nameof Foo
+"""
+                    (set [| 0 |])
+            ]
+        scenario
+            "Nameof module without namespace"
+            [
+                sourceFile
+                    "A.fs"
+                    """
+module Foo
+
+let x = 2
+"""
+                    Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+module Point
+
+let y = nameof Foo
+"""
+                    (set [| 0 |])
+            ]
+        scenario
+            "Single module name should always be checked, regardless of own namespace"
+            [
+                sourceFile "X.fs" "namespace X.Y" Set.empty
+                sourceFile
+                    "A.fs"
+                    """
+module Foo
+
+let x = 2
+"""
+                    Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+namespace X.Y
+
+type T() =
+    let _ = nameof Foo
+"""
+                    (set [| 1 |])
+            ]
+        scenario
+            "nameof pattern"
+            [
+                sourceFile "A.fs" "module Foo" Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+module Bar
+
+do
+    match "" with
+    | nameof Foo -> ()
+    | _ -> ()
+"""
+                    (set [| 0 |])
+            ]
+        scenario
+            "parentheses around module name in nameof pattern"
+            [
+                sourceFile "A.fs" "module Foo" Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+module Bar
+
+do
+    match "" with
+    | nameof ((Foo)) -> ()
+    | _ -> ()
+"""
+                    (set [| 0 |])
+            ]
+            
+        scenario
+            "parentheses around module name in nameof expression"
+            [
+                sourceFile "A.fs" "module Foo" Set.empty
+                sourceFile
+                    "B.fs"
+                    """
+module Bar
+
+let _ = nameof ((Foo))
+"""
+                    (set [| 0 |])
+            ]
     ]