Bump minimum needed R version to 3.6

R 4.3 is scheduled for release on April 21.

Follow-up on #985

DESCRIPTION

@@ -23,7 +23,7 @@ License: MIT + file LICENSE
 URL: https://github.com/r-lib/styler, https://styler.r-lib.org
 BugReports: https://github.com/r-lib/styler/issues
 Depends:
-    R (>= 3.5.0)
+    R (>= 3.6.0)
 Imports: 
     cli (>= 3.1.1),
     magrittr (>= 2.0.0),

R/environments.R

@@ -43,13 +43,7 @@ parser_version_get <- function() {
 
 #' @rdname parser_version_set
 parser_version_find <- function(pd) {
-  ifelse(any(pd$token == "equal_assign"),
-    2L,
-    ifelse(any(pd$token == "expr_or_assign_or_help"),
-      3L,
-      1L
-    )
-  )
+  if (any(pd$token == "equal_assign")) 2L else 3L
 }
 
 

R/parse.R

@@ -105,7 +105,6 @@ get_parse_data <- function(text, include_text = TRUE, ...) {
   pd <- pd %>%
     add_id_and_short()
 
-  parser_version_set(parser_version_find(pd))
   pd
 }
 

R/relevel.R

@@ -25,11 +25,7 @@ flatten_operators <- function(pd_nested) {
 #' @keywords internal
 flatten_operators_one <- function(pd_nested) {
   pd_token_left <- c(special_token, "PIPE", math_token, "'$'")
-  pd_token_right <- c(
-    special_token, "PIPE", "LEFT_ASSIGN",
-    if (parser_version_get() > 1L) "EQ_ASSIGN",
-    "'+'", "'-'", "'~'"
-  )
+  pd_token_right <- c(special_token, "PIPE", "LEFT_ASSIGN", "EQ_ASSIGN", "'+'", "'-'", "'~'")
   pd_nested %>%
     flatten_pd(pd_token_left, left = TRUE) %>%
     flatten_pd(pd_token_right, left = FALSE)
@@ -106,143 +102,3 @@ wrap_expr_in_expr <- function(pd) {
     indents = pd$indent[1L]
   )
 }
-
-
-#   ____________________________________________________________________________
-#   Relocate EQ_ASSIGN                                                      ####
-
-#' Relocate the expressions containing the token `EQ_ASSIGN` within the nested
-#' parse table
-#'
-#' Although syntactically identical, [utils::getParseData()] does not produce
-#' the same hierarchy of the parse table (parent and id relationship) for `<-`
-#' and `=` (See 'Examples').
-#' This is considered to be a bug and causes problems because the
-#' nested parse table constructed with [compute_parse_data_nested()] is not
-#' consistent if `EQ_ASSIGN` occurs in the expression to style. In particular,
-#' `EQ_ASSIGN` and the tokens to its left and right are located too high up in
-#' the hierarchy of the nested parse data. Hence, this function wraps the
-#' sub-expression into an expression, similar to [wrap_expr_in_curly()].
-#' Since `wrap_expr_in_curly()` is called from within a visitor
-#' (and `relocate_eq_assign()` not), we need to
-#' wrap the the implementation [relocate_eq_assign_nest()] that operates on
-#' *nests* into a visitor call.
-#' @param pd A parse table.
-#' @examples
-#' styler:::get_parse_data("a <- b <- 3")
-#' styler:::get_parse_data("a  = b = 3")
-#' styler:::get_parse_data(
-#'   "x = 5
-#'   if(x >= 5)
-#'   y = TRUE else
-#'   y = FALSE",
-#' )
-#' styler:::get_parse_data(
-#'   "x <- 5
-#'   if(x >= 5)
-#'   y <- TRUE else
-#'   y <- FALSE",
-#' )
-#' @keywords internal
-relocate_eq_assign <- function(pd) {
-  if (parser_version_get() < 2L) {
-    post_visit_one(pd, relocate_eq_assign_nest)
-  } else {
-    pd
-  }
-}
-
-
-#' Relocate all assignment expressions that contain `EQ_ASSIGN` within a *nest*
-#'
-#' Implements the relocation of an `EQ_ASSIGN` and associated tokens
-#' within a *nest* (nested parse table at one level of nesting).
-#' Note that one assignment expression (such as "a = b = c") can include
-#' multiple assignment operators, an assignment involves just one assignment
-#' operator.
-#' For the relocation of assignment expressions that contain `EQ_ASSIGN` within
-#' a *nest*, we need to first find the expressions that contain `=` and then
-#' split the *nest* into parse tables each containing one such assignment
-#' expression and then relocate each of them separately.
-#' We can't do all of them together because:
-#'
-#'  * An assignment can contain more than just three tokens, e.g. (a <- b <- c).
-#'  * Two assignments can be in the same nest although they don't belong to the
-#'    same assignment (if-else statement).
-#'
-#' Please refer to the section 'Examples' in [relocate_eq_assign()] for details.
-#' @param pd A parse table.
-#'
-#' @keywords internal
-relocate_eq_assign_nest <- function(pd) {
-  idx_eq_assign <- which(pd$token == "EQ_ASSIGN")
-  if (length(idx_eq_assign) > 0L) {
-    block_id <- find_block_id(pd)
-    blocks <- split(pd, block_id)
-    pd <- map_dfr(blocks, relocate_eq_assign_one)
-  }
-  pd
-}
-
-#' Find the block to which a token belongs
-#'
-#' Two assignment tokens `EQ_ASSIGN` belong to the same block if they are not
-#' separated by more than one token. Token between `EQ_ASSIGN` tokens belong
-#' to the `EQ_ASSIGN` token occurring before them, except the token right before
-#' `EQ_ASSING` already belongs to the `EQ_ASSING` after it. Note that this
-#' notion is unrelated to the column *block* in the parse table, which is used
-#' to [parse_transform_serialize_r()] code blocks and leave out the ones that
-#' are cached.
-#' @param pd A parse table.
-#' @keywords internal
-find_block_id <- function(pd) {
-  idx_eq_assign <- which(pd$token == "EQ_ASSIGN")
-  eq_belongs_to_block <- c(0L, diff(idx_eq_assign) > 2L)
-
-  empty_seq <- rep(0L, nrow(pd))
-  empty_seq[idx_eq_assign - 1L] <- eq_belongs_to_block
-  block_id <- cumsum(empty_seq)
-  block_id
-}
-
-#' Relocate an assignment expression
-#'
-#' Relocates an assignment expression within a parse table containing one
-#' assignment expression. Note that one assignment can include multiple
-#' assignment operators such as "a = b = c".
-#' @param pd A parse table with one assignment expression to relocate.
-#' @keywords internal
-relocate_eq_assign_one <- function(pd) {
-  idx_eq_assign <- which(pd$token == "EQ_ASSIGN")
-  eq_ind <- seq2(idx_eq_assign[1L] - 1L, last(idx_eq_assign) + 1L)
-  # initialize because wrap_expr_in_expr -> create_tokens -> requires it
-  pd$indent <- 0L
-  eq_expr <- pd[eq_ind, ] %>%
-    wrap_expr_in_expr() %>%
-    add_line_col_to_wrapped_expr() %>%
-    remove_attributes(c(
-      "multi_line", "indention_ref_pos_id",
-      "newlines", "indent", "spaces", "lag_newlines"
-    ))
-  eq_expr$id <- NA
-  eq_expr$parent <- NA
-  pd$indent <- NULL
-  non_eq_expr <- pd[-eq_ind, ]
-  pd <- bind_rows(eq_expr, non_eq_expr) %>%
-    arrange_pos_id()
-  pd
-}
-
-#' Adds line and col information to an expression from its child
-#'
-#' @param pd A parse table.
-
-#' @keywords internal
-add_line_col_to_wrapped_expr <- function(pd) {
-  if (nrow(pd) > 1L) abort("pd must be a wrapped expression that has one row.")
-  pd$line1 <- pd$child[[1L]]$line1[1L]
-  pd$line2 <- last(pd$child[[1L]]$line2)
-  pd$col1 <- pd$child[[1L]]$col1[1L]
-  pd$col2 <- last(pd$child[[1L]]$col2)
-  pd
-}

R/style-guides.R

@@ -237,10 +237,6 @@ tidyverse_style <- function(scope = "tokens",
     )
   )
 
-  if (getRversion() < "3.6") {
-    transformers_drop$token$force_assignment_op <- NULL
-  }
-
   style_guide_name <- "styler::tidyverse_style@https://github.com/r-lib"
   create_style_guide(
     # transformer functions