gopls/internal/semtok: change types.Named to types.Basic for iota, true, and false

Fixes golang/go#70219

Change-Id: I4aacfc8f55c2b9bae17b5012cc8967329849cc6c
GitHub-Last-Rev: 88ecf46
GitHub-Pull-Request: #541
Reviewed-on: https://go-review.googlesource.com/c/tools/+/625895
Reviewed-by: Robert Findley <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
Auto-Submit: Robert Findley <[email protected]>

Author: xzbdmw

gopls/internal/golang/semtok.go

@@ -556,7 +556,7 @@ func (tv *tokenVisitor) ident(id *ast.Ident) {
 	case *types.Builtin:
 		emit(semtok.TokFunction, "defaultLibrary")
 	case *types.Const:
-		if is[*types.Named](obj.Type()) &&
+		if is[*types.Basic](obj.Type()) &&
 			(id.Name == "iota" || id.Name == "true" || id.Name == "false") {
 			emit(semtok.TokVariable, "readonly", "defaultLibrary")
 		} else {

gopls/internal/test/marker/testdata/token/builtin_constant.txt

@@ -0,0 +1,21 @@
+This test checks semanticTokens on builtin constants.
+(test for #70219.)
+
+-- settings.json --
+{
+	"semanticTokens": true
+}
+
+-- flags --
+-ignore_extra_diags
+
+-- default_lib_const.go --
+package p
+
+func _() {
+	a, b := false, true //@ token("false", "variable", "readonly defaultLibrary"), token("true", "variable", "readonly defaultLibrary")
+}
+
+const (
+	c = iota //@ token("iota", "variable", "readonly defaultLibrary")
+)