fix #16356, deprecate juxtaposing bin, oct, and hex literals

NEWS.md

@@ -19,6 +19,9 @@ Language changes
  * In string and character literals, backslash `\` may no longer
  precede unrecognized escape characters ([#22800]).
 
+ * Juxtaposing hex literals is deprecated, since it can lead to confusing
+ code such as `0xapi == 0xa * pi` ([#16356]).
+
  * Declaring arguments as `x::ANY` to avoid specialization has been replaced
  by `@nospecialize x`. ([#22666]).
 

src/julia-parser.scm

@@ -337,13 +337,20 @@
  (write-char (read-char port) str)
  (read-digs #t #f)
  (disallow-dot))
- (io.ungetc port c))))
+ (io.ungetc port c)))))
+ (if (and (char? c)
+ (or (eq? pred char-bin?) (eq? pred char-oct?)
+ (and (eq? pred char-hex?) (not is-hex-float-literal)))
+ (or (char-numeric? c)
+ (and (identifier-start-char? c)
+ (syntax-deprecation port ;; remove after v0.7
+ (string (get-output-string str) c)
+ (string (get-output-string str) " * " c))
+ #f))) ;; remove after v0.7
  ;; disallow digits after binary or octal literals, e.g., 0b12
- (if (and (or (eq? pred char-bin?) (eq? pred char-oct?))
- (not (eof-object? c))
- (char-numeric? c))
- (error (string "invalid numeric constant \""
- (get-output-string str) c "\"")))))
+ ;; and disallow identifier chars after hex literals.
+ (error (string "invalid numeric constant \""
+ (get-output-string str) c "\""))))
  (let* ((s (get-output-string str))
  (r (cond ((eq? pred char-hex?) 16)
  ((eq? pred char-oct?) 8)

test/bitarray.jl

@@ -885,8 +885,8 @@ timesofar("unary arithmetic")
  @check_bit_operation broadcast(^, 1.0im, b2) Matrix{Complex128}
  @check_bit_operation broadcast(^, 0im, b2) Matrix{Complex{Int}}
  @check_bit_operation broadcast(^, 1im, b2) Matrix{Complex{Int}}
- @check_bit_operation broadcast(^, 0x0im, b2) Matrix{Complex{UInt8}}
- @check_bit_operation broadcast(^, 0x1im, b2) Matrix{Complex{UInt8}}
+ @check_bit_operation broadcast(^, 0x0*im, b2) Matrix{Complex{UInt8}}
+ @check_bit_operation broadcast(^, 0x1*im, b2) Matrix{Complex{UInt8}}
  end
 
  @testset "Matrix/Number" begin
@@ -982,7 +982,7 @@ timesofar("unary arithmetic")
  @check_bit_operation broadcast(^, b1, 0.0) Matrix{Float64}
  @check_bit_operation broadcast(^, b1, 1.0) Matrix{Float64}
  @check_bit_operation broadcast(^, b1, 0.0im) Matrix{Complex128}
- @check_bit_operation broadcast(^, b1, 0x0im) Matrix{Complex128}
+ @check_bit_operation broadcast(^, b1, 0x0*im) Matrix{Complex128}
  @check_bit_operation broadcast(^, b1, 0im) Matrix{Complex128}
  @test_throws DomainError broadcast(^, b1, -1)
 
@@ -991,7 +991,7 @@ timesofar("unary arithmetic")
  @check_bit_operation broadcast(^, b1, 1.0im) Matrix{Complex128}
  @check_bit_operation broadcast(^, b1, -1im) Matrix{Complex128}
  @check_bit_operation broadcast(^, b1, 1im) Matrix{Complex128}
- @check_bit_operation broadcast(^, b1, 0x1im) Matrix{Complex128}
+ @check_bit_operation broadcast(^, b1, 0x1*im) Matrix{Complex128}
  end
 end