Fix template concat, stil need to fix template parts.

So far this works only if the cursor is *after* the first character.

This will later need to be moved to the syntax repo and synched back.

Author: cristianoc

analysis/tests/src/expected/Completion.res.txt

@@ -1536,10 +1536,10 @@ Completable: Cpath Value[red]
 
 Complete src/Completion.res 402:24
 posCursor:[402:24] posNoWhite:[402:23] Found expr:[400:14->402:31]
-Pexp_apply ...__ghost__[0:-1->0:-1] (...[401:16->402:27], ...[402:27->402:31])
-posCursor:[402:24] posNoWhite:[402:23] Found expr:[401:16->402:27]
-Pexp_apply ...__ghost__[0:-1->0:-1] (...[401:16->402:27], ...[402:24->402:27])
-posCursor:[402:24] posNoWhite:[402:23] Found expr:[401:16->402:27]
+Pexp_apply ...__ghost__[0:-1->0:-1] (...[400:14->402:27], ...[402:27->402:31])
+posCursor:[402:24] posNoWhite:[402:23] Found expr:[400:14->402:27]
+Pexp_apply ...__ghost__[0:-1->0:-1] (...[400:14->402:24], ...[402:24->402:27])
+posCursor:[402:24] posNoWhite:[402:23] Found expr:[400:14->402:24]
 Pexp_apply ...__ghost__[0:-1->0:-1] (...[400:14->401:16], ...[401:16->402:24])
 posCursor:[402:24] posNoWhite:[402:23] Found expr:[401:16->402:24]
 Completable: Cnone

analysis/vendor/res_outcome_printer/res_core.ml

@@ -2155,7 +2155,11 @@ and parseTemplateExpr ?(prefix = "js") p =
     let op = Location.mknoloc (Longident.Lident "^") in
     Ast_helper.Exp.ident op
   in
-  let rec parseParts acc =
+  let concat (e1: Parsetree.expression) (e2: Parsetree.expression) =
+    let loc = mkLoc e1.pexp_loc.loc_start e2.pexp_loc.loc_end in
+    Ast_helper.Exp.apply ~attrs:[templateLiteralAttr] ~loc hiddenOperator
+        [(Nolabel, e1); (Nolabel, e2)] in
+  let rec parseParts (acc: Parsetree.expression) =
     let startPos = p.Parser.startPos in
     Parser.nextTemplateLiteralToken p;
     match p.token with
@@ -2166,25 +2170,18 @@ and parseTemplateExpr ?(prefix = "js") p =
         Ast_helper.Exp.constant ~attrs:[templateLiteralAttr] ~loc
           (Pconst_string (txt, Some prefix))
       in
-      Ast_helper.Exp.apply ~attrs:[templateLiteralAttr] ~loc hiddenOperator
-        [(Nolabel, acc); (Nolabel, str)]
+      concat acc str
     | TemplatePart txt ->
       Parser.next p;
       let loc = mkLoc startPos p.prevEndPos in
       let expr = parseExprBlock p in
-      let fullLoc = mkLoc startPos p.prevEndPos in
       let str =
         Ast_helper.Exp.constant ~attrs:[templateLiteralAttr] ~loc
           (Pconst_string (txt, Some prefix))
       in
       let next =
-        let a =
-          Ast_helper.Exp.apply ~attrs:[templateLiteralAttr] ~loc:fullLoc
-            hiddenOperator
-            [(Nolabel, acc); (Nolabel, str)]
-        in
-        Ast_helper.Exp.apply ~loc:fullLoc hiddenOperator
-          [(Nolabel, a); (Nolabel, expr)]
+        let a = concat acc str in
+        concat a expr
       in
       parseParts next
     | token ->
@@ -2203,15 +2200,11 @@ and parseTemplateExpr ?(prefix = "js") p =
     Parser.next p;
     let constantLoc = mkLoc startPos p.prevEndPos in
     let expr = parseExprBlock p in
-    let fullLoc = mkLoc startPos p.prevEndPos in
     let str =
       Ast_helper.Exp.constant ~attrs:[templateLiteralAttr] ~loc:constantLoc
         (Pconst_string (txt, Some prefix))
     in
-    let next =
-      Ast_helper.Exp.apply ~attrs:[templateLiteralAttr] ~loc:fullLoc
-        hiddenOperator
-        [(Nolabel, str); (Nolabel, expr)]
+    let next = concat str expr 
     in
     parseParts next
   | token ->