Inlay hints for types of consts (#22916)

This adds inlay hint support for the types of consts.

compiler/semstmts.nim

@@ -823,9 +823,11 @@ proc semConst(c: PContext, n: PNode): PNode =
       addToVarSection(c, result, b)
       continue
 
+    var hasUserSpecifiedType = false
     var typ: PType = nil
     if a[^2].kind != nkEmpty:
       typ = semTypeNode(c, a[^2], nil)
+      hasUserSpecifiedType = true
 
     var typFlags: TTypeAllowedFlags = {}
 
@@ -866,6 +868,8 @@ proc semConst(c: PContext, n: PNode): PNode =
     else:
       for j in 0..<a.len-2:
         var v = semIdentDef(c, a[j], skConst)
+        when defined(nimsuggest):
+          v.hasUserSpecifiedType = hasUserSpecifiedType
         if sfGenSym notin v.flags: addInterfaceDecl(c, v)
         elif v.owner == nil: v.owner = getCurrOwner(c)
         styleCheckDef(c, v)

compiler/suggest.nim

@@ -158,7 +158,10 @@ proc symToSuggest*(g: ModuleGraph; s: PSym, isLocal: bool, section: IdeCmd, info
       result.qualifiedPath.add(s.name.s)
 
     if s.typ != nil:
-      result.forth = typeToString(s.typ)
+      if section == ideInlayHints:
+        result.forth = typeToString(s.typ, preferInlayHint)
+      else:
+        result.forth = typeToString(s.typ)
     else:
       result.forth = ""
     when defined(nimsuggest) and not defined(noDocgen) and not defined(leanCompiler):

compiler/types.nim

@@ -30,6 +30,7 @@ type
     preferMixed,
       # most useful, shows: symbol + resolved symbols if it differs, e.g.:
       # tuple[a: MyInt{int}, b: float]
+    preferInlayHint,
 
   TTypeRelation* = enum      # order is important!
     isNone, isConvertible,
@@ -512,7 +513,7 @@ const
     "void", "iterable"]
 
 const preferToResolveSymbols = {preferName, preferTypeName, preferModuleInfo,
-  preferGenericArg, preferResolved, preferMixed}
+  preferGenericArg, preferResolved, preferMixed, preferInlayHint}
 
 template bindConcreteTypeToUserTypeClass*(tc, concrete: PType) =
   tc.add concrete
@@ -546,7 +547,10 @@ proc typeToString(typ: PType, prefer: TPreferedDesc = preferName): string =
     if prefer in preferToResolveSymbols and t.sym != nil and
          sfAnon notin t.sym.flags and t.kind != tySequence:
       if t.kind == tyInt and isIntLit(t):
-        result = t.sym.name.s & " literal(" & $t.n.intVal & ")"
+        if prefer == preferInlayHint:
+          result = t.sym.name.s
+        else:
+          result = t.sym.name.s & " literal(" & $t.n.intVal & ")"
       elif t.kind == tyAlias and t[0].kind != tyAlias:
         result = typeToString(t[0])
       elif prefer in {preferResolved, preferMixed}:
@@ -562,7 +566,7 @@ proc typeToString(typ: PType, prefer: TPreferedDesc = preferName): string =
           result = t.sym.name.s
         if prefer == preferMixed and result != t.sym.name.s:
           result = t.sym.name.s & "{" & result & "}"
-      elif prefer in {preferName, preferTypeName} or t.sym.owner.isNil:
+      elif prefer in {preferName, preferTypeName, preferInlayHint} or t.sym.owner.isNil:
         # note: should probably be: {preferName, preferTypeName, preferGenericArg}
         result = t.sym.name.s
         if t.kind == tyGenericParam and t.len > 0:
@@ -581,8 +585,11 @@ proc typeToString(typ: PType, prefer: TPreferedDesc = preferName): string =
       if not isIntLit(t) or prefer == preferExported:
         result = typeToStr[t.kind]
       else:
-        if prefer == preferGenericArg:
+        case prefer:
+        of preferGenericArg:
           result = $t.n.intVal
+        of preferInlayHint:
+          result = "int"
         else:
           result = "int literal(" & $t.n.intVal & ")"
     of tyGenericInst, tyGenericInvocation:

nimsuggest/nimsuggest.nim

@@ -1115,7 +1115,7 @@ proc executeNoHooksV3(cmd: IdeCmd, file: AbsoluteFile, dirtyfile: AbsoluteFile,
     i += parseInt(tag, endCol, i)
     let s = graph.findSymDataInRange(file, line, col, endLine, endCol)
     for q in s:
-      if q.sym.kind in {skLet, skVar, skForVar} and q.isDecl and not q.sym.hasUserSpecifiedType:
+      if q.sym.kind in {skLet, skVar, skForVar, skConst} and q.isDecl and not q.sym.hasUserSpecifiedType:
         graph.suggestInlayHintResult(q.sym, q.info, ideInlayHints)
   else:
     myLog fmt "Discarding {cmd}"