Parse arr[end] differently from arr[var"end"]

src/expr.jl

@@ -76,6 +76,10 @@
         return k == K"error" ?
             Expr(:error) :
             Expr(:error, "$(_token_error_descriptions[k]): `$(source[srcrange])`")
+    elseif k == K"begin" # begin/end as firstindex/lastindex
+        return Expr(:begin)
+    elseif k == K"end"
+        return Expr(:end)
     else
         val = isnothing(node) ?
             parse_julia_literal(txtbuf, head, srcrange .+ txtbuf_offset) :

src/parser.jl

@@ -15,7 +15,7 @@ struct ParseState
     space_sensitive::Bool
     # Seeing `for` stops parsing macro arguments and makes a generator
     for_generator::Bool
-    # Treat 'end' like a normal symbol instead of a reserved word
+    # Treat begin/end like special symbols instead of reserved words
     end_symbol::Bool
     # Treat newline like ordinary whitespace instead of as a potential separator
     whitespace_newline::Bool
@@ -3627,6 +3627,10 @@ function parse_atom(ps::ParseState, check_identifiers=true, has_unary_prefix=fal
         elseif check_identifiers && is_closing_token(ps, leading_kind)
             # :(end)  ==>  (quote-: (error end))
             bump(ps, error="invalid identifier")
+        elseif ps.end_symbol && leading_kind in KSet"begin end" && ps.stream.version >= (1, 13)
+            # https://github.com/JuliaLang/julia/issues/57269
+            # Parse a[begin] differently from a[var"begin"]
+            bump(ps)
         else
             # Remap keywords to identifiers.
             # :end  ==>  (quote-: end)

test/parser.jl

@@ -410,6 +410,9 @@ tests = [
         "(a=1)[]" =>  "(ref (parens (= a 1)))"
         "a[end]"  =>  "(ref a end)"
         "a[begin]"  =>  "(ref a begin)"
+        "a[var\"end\"]"  =>  "(ref a (var end))"
+        "a[var\"begin\"]"  =>  "(ref a (var begin))"
+        "a[var\"test\"]"  =>  "(ref a (var test))"
         "a[:(end)]" => "(typed_hcat a (quote-: (parens (error-t))) (error-t))"
         "T[x   y]"  =>  "(typed_hcat T x y)"
         "T[x ; y]"  =>  "(typed_vcat T x y)"
@@ -1153,11 +1156,19 @@ parsestmt_with_kind_tests = [
     "a >>= b" => "(op= a::Identifier >>::Identifier b::Identifier)"
     ":+="    => "(quote-: +=::op=)"
     ":.+="   => "(quote-: (. +=::op=))"
+    ((v=v"1.13",), "a[begin]") => "(ref a::Identifier begin::begin)"
+    ((v=v"1.13",), "a[end]") => "(ref a::Identifier end::end)"
 ]
 
 @testset "parser `Kind` remapping" begin
     @testset "$(repr(input))" for (input, output) in parsestmt_with_kind_tests
-        input = ((show_kind=true,), input)
+        if !(input isa AbstractString)
+            opts, input_s = input
+        else
+            opts = NamedTuple()
+            input_s = input
+        end
+        input = ((show_kind=true, opts...), input_s)
         test_parse(JuliaSyntax.parse_stmts, input, output)
     end
 end