fix tag function location on error

CHANGELOG.md

@@ -29,6 +29,7 @@
 
 #### :bug: Bug Fix
 
+- Fix tag function location on compiler error. https://github.com/rescript-lang/rescript-compiler/pull/6816
 - Fix encoding inside tagged template literals. https://github.com/rescript-lang/rescript-compiler/pull/6810
 - Fix unhandled cases for exotic idents (allow to use exotic PascalCased identifiers for types). https://github.com/rescript-lang/rescript-compiler/pull/6777
 - PPX v4: mark props type in externals as `@live` to avoid dead code warnings for prop fields in the editor tooling. https://github.com/rescript-lang/rescript-compiler/pull/6796

jscomp/build_tests/super_errors/expected/unknown_tagged_template_function.res.expected

@@ -0,0 +1,7 @@
+
+  We've found a bug for you!
+  /.../fixtures/unknown_tagged_template_function.res:1:11-14
+
+  1 │ let res = tagg`| 5 × 10 = ${5} |`
+
+  The value tagg can't be found

jscomp/build_tests/super_errors/fixtures/unknown_tagged_template_function.res

@@ -0,0 +1 @@
+let res = tagg`| 5 × 10 = ${5} |`

jscomp/syntax/src/res_core.ml

@@ -2286,7 +2286,6 @@ and parse_template_expr ?prefix p =
       Some prefix
     | _ -> Some "js"
   in
-  let start_pos = p.Parser.start_pos in
 
   let parse_parts p =
     let rec aux acc =
@@ -2319,13 +2318,9 @@ and parse_template_expr ?prefix p =
   let parts = parse_parts p in
   let strings = List.map fst parts in
   let values = Ext_list.filter_map parts snd in
-  let end_pos = p.Parser.end_pos in
 
-  let gen_tagged_template_call lident =
-    let ident =
-      Ast_helper.Exp.ident ~attrs:[] ~loc:Location.none
-        (Location.mknoloc lident)
-    in
+  let gen_tagged_template_call (lident_loc : Longident.t Location.loc) =
+    let ident = Ast_helper.Exp.ident ~attrs:[] ~loc:lident_loc.loc lident_loc in
     let strings_array =
       Ast_helper.Exp.array ~attrs:[] ~loc:Location.none strings
     in
@@ -2334,7 +2329,7 @@ and parse_template_expr ?prefix p =
     in
     Ast_helper.Exp.apply
       ~attrs:[tagged_template_literal_attr]
-      ~loc:(mk_loc start_pos end_pos) ident
+      ~loc:lident_loc.loc ident
       [(Nolabel, strings_array); (Nolabel, values_array)]
   in
 
@@ -2374,7 +2369,7 @@ and parse_template_expr ?prefix p =
   match prefix with
   | Some {txt = Longident.Lident ("js" | "j" | "json"); _} | None ->
     gen_interpolated_string ()
-  | Some {txt = lident} -> gen_tagged_template_call lident
+  | Some lident_loc -> gen_tagged_template_call lident_loc
 
 (* Overparse: let f = a : int => a + 1, is it (a : int) => or (a): int =>
  * Also overparse constraints: