fix: add type specifiers to interpolated strings (#4646)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dbrattli

src/Fable.Compiler/ProjectCracker.fs

@@ -706,7 +706,7 @@ let getFableLibraryPath (opts: CrackerOptions) (shouldCopy: bool) =
                 |}
             |> Option.defaultWith (fun () ->
                 Fable.FableError
-                    $"Cannot find [temp/]{buildDir} from {baseDir}.\nPlease, make sure you build {buildDir}"
+                    $"Cannot find [temp/]%s{buildDir} from %s{baseDir}.\nPlease, make sure you build %s{buildDir}"
                 |> raise
             )
 
@@ -786,7 +786,7 @@ let loadPrecompiledInfo (opts: CrackerOptions) otherOptions sourceFiles =
         // Check if precompiled compiler version and options match
         if info.CompilerVersion <> Literals.VERSION then
             Fable.FableError(
-                $"Library was precompiled using Fable v{info.CompilerVersion} but you're using v{Literals.VERSION}. Please use same version."
+                $"Library was precompiled using Fable v%s{info.CompilerVersion} but you're using v%s{Literals.VERSION}. Please use same version."
             )
             |> raise
 
@@ -816,7 +816,7 @@ let loadPrecompiledInfo (opts: CrackerOptions) otherOptions sourceFiles =
                         |> List.map (fun f -> "    " + File.relPathToCurDir f)
                         |> String.concat Log.newLine
                     // TODO: This should likely be an error but make it a warning for now
-                    Log.warning ($"Detected outdated files in precompiled lib:{Log.newLine}{outdated}")
+                    Log.warning ($"Detected outdated files in precompiled lib:%s{Log.newLine}%s{outdated}")
         with er ->
             Log.warning ("Cannot check timestamp of precompiled files: " + er.Message)
 
@@ -849,7 +849,7 @@ let getFullProjectOpts (resolver: ProjectCrackerResolver) (opts: CrackerOptions)
                 if not isOlder then
                     Log.verbose (
                         lazy
-                            $"Cached project info ({cacheTimestamp}) will be discarded because {File.relPathToCurDir filePath} ({fileTimestamp}) is newer"
+                            $"Cached project info (%O{cacheTimestamp}) will be discarded because %s{File.relPathToCurDir filePath} (%O{fileTimestamp}) is newer"
                     )
 
                 isOlder
@@ -911,7 +911,7 @@ let getFullProjectOpts (resolver: ProjectCrackerResolver) (opts: CrackerOptions)
                                 else
                                     "Debug"
 
-                            $"Won't reuse compiled files because last compilation was for {otherMode} mode"
+                            $"Won't reuse compiled files because last compilation was for %s{otherMode} mode"
                     )
 
                 isMostRecent

src/Fable.Compiler/Util.fs

@@ -316,16 +316,16 @@ module File =
                             let creationTime = File.GetCreationTime(lockFile)
 
                             if (DateTime.Now - creationTime).TotalMilliseconds > float timeoutMs then
-                                Log.always $"Found old lock file {relPathToCurDir lockFile} ({creationTime})"
+                                Log.always $"Found old lock file %s{relPathToCurDir lockFile} (%O{creationTime})"
 
                                 try
                                     File.Delete(lockFile)
                                 with _ ->
                                     ()
                             else
-                                Log.always $"Directory is locked, waiting for max {timeoutMs / 1000}s"
+                                Log.always $"Directory is locked, waiting for max %d{timeoutMs / 1000}s"
 
-                                Log.always $"If compiler gets stuck, delete {relPathToCurDir lockFile}"
+                                Log.always $"If compiler gets stuck, delete %s{relPathToCurDir lockFile}"
                         elif waitedMs >= timeoutMs then
                             Fable.AST.Fable.FableError "LockTimeOut" |> raise
 
@@ -348,7 +348,7 @@ module File =
                 if fileCreated then
                     File.Delete(lockFile)
             with e ->
-                Log.always $"Could not delete lock file: {lockFile} ({e.Message})"
+                Log.always $"Could not delete lock file: %s{lockFile} (%s{e.Message})"
 
 [<RequireQualifiedAccess>]
 module Process =
@@ -388,7 +388,7 @@ module Process =
     let findInPath (exec: string) =
         match tryFindInPath exec with
         | Some exec -> exec
-        | None -> failwith $"Cannot find {exec} in PATH"
+        | None -> failwith $"Cannot find %s{exec} in PATH"
 
     let getCurrentAssembly () = typeof<TypeInThisAssembly>.Assembly
 
@@ -413,7 +413,7 @@ module Process =
         // TODO: We should use cliArgs.RootDir instead of Directory.GetCurrentDirectory here but it's only informative
         // so let's leave it as is for now to avoid having to pass the cliArgs through all the call sites
         if not redirectOutput then
-            Log.always $"""{File.relPathToCurDir workingDir}> {exePath} {String.concat " " args}"""
+            Log.always $"""%s{File.relPathToCurDir workingDir}> %s{exePath} %s{String.concat " " args}"""
 
         let psi = ProcessStartInfo(exePath)
 
@@ -616,7 +616,7 @@ module Imports =
             let importPath = Path.Combine(projDir, importPath)
             let targetDir = Path.GetDirectoryName(targetPath)
             getRelativePath targetDir importPath
-        | Some macro, _ -> failwith $"Unknown import macro: {macro}"
+        | Some macro, _ -> failwith $"Unknown import macro: %s{macro}"
         | None, None ->
             if isAbsolutePath importPath then
                 let sourceDir = Path.GetDirectoryName(sourcePath)
@@ -934,7 +934,7 @@ type PrecompiledInfoImpl(fableModulesDir: string, info: PrecompiledInfoJson) =
         IO.Path.Combine(fableModulesDir, "precompiled_info.json")
 
     static member GetInlineExprsPath(fableModulesDir, index: int) =
-        IO.Path.Combine(fableModulesDir, "inline_exprs", $"inline_exprs_{index}.json")
+        IO.Path.Combine(fableModulesDir, "inline_exprs", $"inline_exprs_%d{index}.json")
 
     static member Load(fableModulesDir: string) =
         try

src/Fable.Transforms/BabelPrinter.fs

@@ -450,7 +450,7 @@ module PrinterExtensions =
                 |> List.iter (
                     function
                     | _, NullOrUndefinedOrVoid -> ()
-                    | key, StringConstant value -> printProp (fun () -> printer.Print($"{key}=\"{value}\""))
+                    | key, StringConstant value -> printProp (fun () -> printer.Print($"%s{key}=\"%s{value}\""))
                     | key, value ->
                         printProp (fun () ->
                             printer.Print(key + "={")

src/Fable.Transforms/Dart/Fable2Dart.fs

@@ -180,7 +180,7 @@ module Util =
             match transformAndCaptureExpr com ctx entRef with
             | [], IdentExpression ident -> Some ident
             | _ ->
-                addError com [] None $"Unexpected, entity ref for {ent.FullName} is not an identifier"
+                addError com [] None $"Unexpected, entity ref for %s{ent.FullName} is not an identifier"
 
                 None
         )
@@ -1956,17 +1956,17 @@ module Util =
             match transformCallArgs com ctx (CallInfo info) with
             | [], args -> args
             | _, args ->
-                $"Rewrite base arguments for {classDecl.Entity.FullName} so they can be compiled as Dart expressions"
+                $"Rewrite base arguments for %s{classDecl.Entity.FullName} so they can be compiled as Dart expressions"
                 |> addWarning com [] e.Range
 
                 args
         | Some(Fable.Value _ as e) ->
-            $"Ignoring base call for {classDecl.Entity.FullName}"
+            $"Ignoring base call for %s{classDecl.Entity.FullName}"
             |> addWarning com [] e.Range
 
             []
         | Some e ->
-            $"Unexpected base call for {classDecl.Entity.FullName}"
+            $"Unexpected base call for %s{classDecl.Entity.FullName}"
             |> addError com [] e.Range
 
             []
@@ -2316,7 +2316,7 @@ module Util =
                 let name =
                     match p.Name with
                     | Some name -> name
-                    | None -> $"arg{i}$"
+                    | None -> $"arg%d{i}$"
 
                 let t = transformType com ctx p.Type
                 FunctionArg(makeImmutableIdent t name) // TODO, isOptional=p.IsOptional, isNamed=p.IsNamed)
@@ -2391,7 +2391,7 @@ module Util =
         =
         match implementsIterable, baseType with
         | Some iterable, Some _ ->
-            $"Types implementing IEnumerable cannot inherit from another class: {classEnt.FullName}"
+            $"Types implementing IEnumerable cannot inherit from another class: %s{classEnt.FullName}"
             |> addError com [] None
 
             Some iterable

src/Fable.Transforms/Dart/Replacements.fs

@@ -640,7 +640,7 @@ let tryEntityIdent (com: Compiler) entFullName =
     | BuiltinDefinition(FSharpReference _) -> makeImportLib com MetaType "FSharpRef" "Types" |> Some
     | BuiltinDefinition(FSharpResult _) -> makeImportLib com MetaType "FSharpResult$2" "Result" |> Some
     | BuiltinDefinition(FSharpChoice genArgs) ->
-        let membName = $"FSharpChoice${List.length genArgs}"
+        let membName = $"FSharpChoice$%d{List.length genArgs}"
         makeImportLib com MetaType membName "Choice" |> Some
     // | BuiltinDefinition BclGuid -> jsTypeof "string" expr
     | BuiltinDefinition(BclHashSet _)
@@ -1387,7 +1387,7 @@ let strings (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr opt
     | "GetEnumerator", Some c, _ -> stringToCharSeq c |> getEnumerator com r t |> Some
     | ("Contains" | "StartsWith" | "EndsWith" as meth), Some c, arg :: _ ->
         if List.isMultiple args then
-            addWarning com ctx.InlinePath r $"String.{meth}: second argument is ignored"
+            addWarning com ctx.InlinePath r $"String.%s{meth}: second argument is ignored"
 
         Helper.InstanceCall(c, Naming.lowerFirst meth, t, [ arg ], ?loc = r) |> Some
     | ReplaceName [ "ToUpper", "toUpperCase"
@@ -3158,7 +3158,7 @@ let random (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr opti
     | meth, Some thisArg ->
         let meth =
             if meth = "Next" then
-                $"Next{List.length args}"
+                $"Next%d{List.length args}"
             else
                 meth
 
@@ -3273,7 +3273,7 @@ let regex com (ctx: Context) r t (i: CallInfo) (thisArg: Expr option) (args: Exp
         match thisArg, args with
         | Some thisArg, args ->
             if args.Length > 2 then
-                $"Regex.{meth} doesn't support more than 2 arguments"
+                $"Regex.%s{meth} doesn't support more than 2 arguments"
                 |> addError com ctx.InlinePath r
 
             thisArg :: args |> Some
@@ -4194,6 +4194,6 @@ let tryType typ =
         | FSharpMap(key, value) -> Some(Types.fsharpMap, maps, [ key; value ])
         | FSharpSet genArg -> Some(Types.fsharpSet, sets, [ genArg ])
         | FSharpResult(genArg1, genArg2) -> Some(Types.result, results, [ genArg1; genArg2 ])
-        | FSharpChoice genArgs -> Some($"{Types.choiceNonGeneric}`{List.length genArgs}", results, genArgs)
+        | FSharpChoice genArgs -> Some($"%s{Types.choiceNonGeneric}`%d{List.length genArgs}", results, genArgs)
         | FSharpReference genArg -> Some(Types.refCell, refCells, [ genArg ])
     | _ -> None

src/Fable.Transforms/FSharp2Fable.Util.fs

@@ -2595,16 +2595,19 @@ module Util =
     let failReplace (com: IFableCompiler) ctx r (info: Fable.ReplaceCallInfo) (thisArg: Fable.Expr option) =
         let msg =
             if info.DeclaringEntityFullName.StartsWith("Fable.Core.", StringComparison.Ordinal) then
-                $"{info.DeclaringEntityFullName}.{info.CompiledName} is not supported, try updating fable tool"
+                $"%s{info.DeclaringEntityFullName}.%s{info.CompiledName} is not supported, try updating fable tool"
             else
                 com.WarnOnlyOnce(
                     "Fable only supports a subset of standard .NET API, please check https://fable.io/docs/dotnet/compatibility.html. For external libraries, check whether they are Fable-compatible in the package docs."
                 )
 
-                $"""{info.DeclaringEntityFullName}.{info.CompiledName}{if Option.isSome thisArg then
-                                                                           ""
-                                                                       else
-                                                                           " (static)"} is not supported by Fable"""
+                let staticSuffix =
+                    if Option.isSome thisArg then
+                        ""
+                    else
+                        " (static)"
+
+                $"%s{info.DeclaringEntityFullName}.%s{info.CompiledName}%s{staticSuffix} is not supported by Fable"
 
         msg |> addErrorAndReturnNull com ctx.InlinePath r
 

src/Fable.Transforms/FSharp2Fable.fs

@@ -111,7 +111,7 @@ let private transformNewUnion com ctx r fsType (unionCase: FSharpUnionCase) (arg
         match argExprs with
         | [] -> transformStringEnum rule unionCase
         | _ ->
-            $"StringEnum types cannot have fields: {tdef.TryFullName}"
+            $"StringEnum types cannot have fields: %O{tdef.TryFullName}"
             |> addErrorAndReturnNull com ctx.InlinePath r
 
     | OptionUnion(typ, isStruct) ->
@@ -723,7 +723,7 @@ let private transformExpr (com: IFableCompiler) (ctx: Context) appliedGenArgs fs
                 let! limit = transformExpr com ctx [] limit
                 let! body = transformExpr com newContext [] body
                 return makeForLoop r isUp ident start limit body
-            | _ -> return failwithf $"Unexpected loop {r}: %A{fsExpr}"
+            | _ -> return failwithf $"Unexpected loop %O{r}: %A{fsExpr}"
 
         | FSharpExprPatterns.WhileLoop(guardExpr, bodyExpr, _) ->
             let! guardExpr = transformExpr com ctx [] guardExpr
@@ -1686,7 +1686,7 @@ let private applyJsPyDecorators
             let parameters =
                 memb.CurriedParameterGroups
                 |> Seq.collect id
-                |> Seq.mapi (fun i p -> defaultArg p.Name $"arg{i}", makeType Map.empty p.Type)
+                |> Seq.mapi (fun i p -> defaultArg p.Name $"arg%d{i}", makeType Map.empty p.Type)
                 |> Seq.toList
 
             Replacements.Api.makeMethodInfo com None name parameters returnType
@@ -2760,7 +2760,7 @@ type FableCompiler(com: Compiler) =
         |> List.filter (fun (i, v) ->
             if ctx.CapturedBindings.Contains(i.Name) && canHaveSideEffects com v then
                 if isIdentUsed i.Name resolved then
-                    $"Inlined argument {i.Name} is being captured but is also used somewhere else. "
+                    $"Inlined argument %s{i.Name} is being captured but is also used somewhere else. "
                     + "There's a risk of double evaluation."
                     |> addWarning com [] i.Range
 

src/Fable.Transforms/Fable2Babel.fs

@@ -754,10 +754,10 @@ module Annotation =
         | Replacements.Util.FSharpMap(key, value) ->
             makeFableLibImportTypeAnnotation com ctx [ key; value ] "Map" "FSharpMap"
         | Replacements.Util.FSharpResult(ok, err) ->
-            $"FSharpResult$2{Util.UnionHelpers.UNION_SUFFIX}"
+            $"FSharpResult$2%s{Util.UnionHelpers.UNION_SUFFIX}"
             |> makeFableLibImportTypeAnnotation com ctx [ ok; err ] "Result"
         | Replacements.Util.FSharpChoice genArgs ->
-            $"FSharpChoice${List.length genArgs}{Util.UnionHelpers.UNION_SUFFIX}"
+            $"FSharpChoice$%d{List.length genArgs}%s{Util.UnionHelpers.UNION_SUFFIX}"
             |> makeFableLibImportTypeAnnotation com ctx genArgs "Choice"
         | Replacements.Util.FSharpReference genArg ->
             if isInRefOrAnyType com typ then
@@ -772,7 +772,7 @@ module Annotation =
             | _ -> argTypes
             |> List.mapi (fun i argType ->
                 FunctionTypeParam.functionTypeParam (
-                    Identifier.identifier ($"arg{i}"),
+                    Identifier.identifier ($"arg%d{i}"),
                     makeTypeAnnotation com ctx argType
                 )
             )
@@ -1034,7 +1034,7 @@ module Util =
                         if selector.StartsWith("*", StringComparison.Ordinal) then
                             selector
                         else
-                            $"default as {selector}"
+                            $"default as %s{selector}"
 
                     com.GetImportExpr(ctx, selector, path, r, noMangle = true) |> ignore
 
@@ -1631,7 +1631,7 @@ module Util =
                         Expression.callExpression (helperRef, values, typeArguments = typeParams)
                     | None -> callConstructor (Some case)
                 | None ->
-                    $"Unmatched union case tag: {tag} for {ent.FullName}" |> addWarning com [] r
+                    $"Unmatched union case tag: %d{tag} for %s{ent.FullName}" |> addWarning com [] r
 
                     callConstructor None
             else
@@ -2676,7 +2676,8 @@ but thanks to the optimisation done below we get
                 match List.tryItem tag ent.UnionCases with
                 | Some case -> Some case.Name
                 | None ->
-                    $"Unmatched union case tag: {tag} for {ent.FullName}" |> addWarning com [] range
+                    $"Unmatched union case tag: %d{tag} for %s{ent.FullName}"
+                    |> addWarning com [] range
 
                     None
             | _ -> None
@@ -4742,7 +4743,7 @@ but thanks to the optimisation done below we get
                     let noConflict = ctx.UsedNames.RootScope.Add(alias)
 
                     if not noConflict then
-                        com.WarnOnlyOnce($"Import {alias} conflicts with existing identifier in root scope")
+                        com.WarnOnlyOnce($"Import %s{alias} conflicts with existing identifier in root scope")
 
                     alias
                 else

src/Fable.Transforms/FableTransforms.fs

@@ -599,7 +599,7 @@ module private Transforms =
                 match expr with
                 | IdentExpr _ -> None, expr
                 | arg ->
-                    let ident = makeTypedIdent argType $"anonRec{com.IncrementCounter()}"
+                    let ident = makeTypedIdent argType $"anonRec%d{com.IncrementCounter()}"
 
                     Some(ident, arg), IdentExpr ident
 

src/Fable.Transforms/OverloadSuffix.fs

@@ -60,7 +60,7 @@ let rec private getTypeFastFullName (genParams: IDictionary<_, _>) (t: Fable.Typ
         let typeName = getTypeFastFullName genParams genArg
 
         if isStruct then
-            $"System.Nullable<{typeName}>"
+            $"System.Nullable<%s{typeName}>"
         else
             // there is no overload distinction for nullable reference types,
             // so the name and overload suffix are the same as the inner type