InterpolatedStringWithNoSubstitution: impl rule

Implemented InterpolatedStringWithNoSubstitution rule.

Author: webwarrior-ws

src/FSharpLint.Core/Rules/Smells/InterpolatedStringWithNoSubstitution.fs

@@ -7,13 +7,38 @@ open FSharp.Compiler.Syntax
 open FSharpLint.Framework.Ast
 open FSharpLint.Framework.Rules
 
-let checkInterpolatedString (contents: list<SynInterpolatedStringPart>) range =
-    failwith "Not yet implemented"
+let private makeWarning range =
+    {
+        Range = range
+        Message = Resources.GetString "InterpolatedStringWithNoSubstitution"
+        SuggestedFix = None
+        TypeChecks = List.Empty
+    }
 
+let checkInterpolatedString (contents: List<SynInterpolatedStringPart>) range =
+    if contents |> List.exists (fun part -> part.IsFillExpr) then
+        Array.empty
+    else
+        Array.singleton (makeWarning range)
+
+let stringFormattingFunctionNames = [ "sprintf"; "failwithf" ]
+
+// https://learn.microsoft.com/en-us/dotnet/fsharp/language-reference/plaintext-formatting#format-specifiers-for-printf
+let formatSpecifierRegex = Text.RegularExpressions.Regex(@"($|[^\%])\%[^\s\%]")
+
+let checkFormattingFunctionApplication (formatString: string) range =
+    if formatSpecifierRegex.IsMatch formatString then
+        Array.empty
+    else
+        Array.singleton (makeWarning range)
+            
 let runner (args: AstNodeRuleParams) =
     match args.AstNode with
     | AstNode.Expression(SynExpr.InterpolatedString(contents, _synStringKind, range)) ->
         checkInterpolatedString contents range
+    | AstNode.Expression(SynExpr.App(_, false, SynExpr.Ident(ident), SynExpr.Const(SynConst.String(text, _, _stringRange),_), range))
+        when stringFormattingFunctionNames |> List.contains ident.idText ->
+        checkFormattingFunctionApplication text range
     | _ -> Array.empty
 
 let rule =

src/FSharpLint.Core/Text.resx

@@ -381,4 +381,7 @@
   <data name="RulesFavourAsKeyword" xml:space="preserve">
     <value>Prefer using the 'as' pattern to match a constant and bind it to a variable.</value>
   </data>
+  <data name="InterpolatedStringWithNoSubstitution" xml:space="preserve">
+    <value>Use interpolated string (with $ prefix) only when embedding F# expression in that string using {}.</value>
+  </data>
 </root>