improve inferrabilities within TOML module (#38831)

* improve inferrability within TOML module

* simplify with `@try` macro

* apply suggestion, use `Int64`

base/toml_parser.jl

@@ -925,21 +925,21 @@ ok_end_value(c::Char) = iswhitespace(c) || c == '#' || c == EOF_CHAR || c == ']'
 accept_two(l, f::F) where {F} = accept_n(l, 2, f) || return(ParserError(ErrParsingDateTime))
 function parse_datetime(l)
  # Year has already been eaten when we reach here
- year = parse_int(l, false)::Int64
+ year = @try parse_int(l, false)
  year in 0:9999 || return ParserError(ErrParsingDateTime)
 
  # Month
  accept(l, '-') || return ParserError(ErrParsingDateTime)
  set_marker!(l)
  @try accept_two(l, isdigit)
- month = parse_int(l, false)
+ month = @try parse_int(l, false)
  month in 1:12 || return ParserError(ErrParsingDateTime)
  accept(l, '-') || return ParserError(ErrParsingDateTime)
 
  # Day
  set_marker!(l)
  @try accept_two(l, isdigit)
- day = parse_int(l, false)
+ day = @try parse_int(l, false)
  # Verify the real range in the constructor below
  day in 1:31 || return ParserError(ErrParsingDateTime)
 
@@ -976,9 +976,10 @@ function parse_datetime(l)
 end
 
 function try_return_datetime(p, year, month, day, h, m, s, ms)
- if p.Dates !== nothing
+ Dates = p.Dates
+ if Dates !== nothing
  try
- return p.Dates.DateTime(year, month, day, h, m, s, ms)
+ return Dates.DateTime(year, month, day, h, m, s, ms)
  catch
  return ParserError(ErrParsingDateTime)
  end
@@ -988,9 +989,10 @@ function try_return_datetime(p, year, month, day, h, m, s, ms)
 end
 
 function try_return_date(p, year, month, day)
- if p.Dates !== nothing
+ Dates = p.Dates
+ if Dates !== nothing
  try
- return p.Dates.Date(year, month, day)
+ return Dates.Date(year, month, day)
  catch
  return ParserError(ErrParsingDateTime)
  end
@@ -1000,7 +1002,7 @@ function try_return_date(p, year, month, day)
 end
 
 function parse_local_time(l::Parser)
- h = parse_int(l, false)
+ h = @try parse_int(l, false)
  h in 0:23 || return ParserError(ErrParsingDateTime)
  _, m, s, ms = @try _parse_local_time(l, true)
  # TODO: Could potentially parse greater accuracy for the
@@ -1009,9 +1011,10 @@ function parse_local_time(l::Parser)
 end
 
 function try_return_time(p, h, m, s, ms)
- if p.Dates !== nothing
+ Dates = p.Dates
+ if Dates !== nothing
  try
- return p.Dates.Time(h, m, s, ms)
+ return Dates.Time(h, m, s, ms)
  catch
  return ParserError(ErrParsingDateTime)
  end
@@ -1133,7 +1136,7 @@ function parse_string_continue(l::Parser, multiline::Bool, quoted::Bool)::Err{St
  if !accept_n(l, n, isvalid_hex)
  return ParserError(ErrInvalidUnicodeScalar)
  end
- codepoint = parse_int(l, false, 16)
+ codepoint = parse_int(l, false, 16)::Int64
  #=
  Unicode Scalar Value
  ---------------------