fix #26571, use 10 as the default base in parse(T, ::Char)

NEWS.md

@@ -456,6 +456,9 @@ This section lists changes that do not have deprecation warnings.
 
  * `indexin` now returns the first rather than the last matching index ([#25998]).
 
+ * `parse(::Type, ::Char)` now uses a default base of 10, like other number parsing
+ methods, instead of 36 ([#26576]).
+
 Library improvements
 --------------------
 

base/parse.jl

@@ -33,7 +33,7 @@ julia> parse(Complex{Float64}, "3.2e-1 + 4.5im")
 """
 parse(T::Type, str; base = Int)
 
-function parse(::Type{T}, c::AbstractChar; base::Integer = 36) where T<:Integer
+function parse(::Type{T}, c::AbstractChar; base::Integer = 10) where T<:Integer
  a::Int = (base <= 36 ? 10 : 36)
  2 <= base <= 62 || throw(ArgumentError("invalid base: base must be 2 ≤ base ≤ 62, got $base"))
  d = '0' <= c <= '9' ? c-'0' :

test/parse.jl

@@ -23,8 +23,12 @@
 @test parse(Int,"-10") == -10
 @test parse(Int64,"3830974272") == 3830974272
 @test parse(Int64,"-3830974272") == -3830974272
+
 @test parse(Int,'3') == 3
 @test parse(Int,'3', base = 8) == 3
+@test parse(Int, 'a', base=16) == 10
+@test_throws ArgumentError parse(Int, 'a')
+@test_throws ArgumentError parse(Int,typemax(Char))
 
 # Issue 20587
 for T in Any[BigInt, Int128, Int16, Int32, Int64, Int8, UInt128, UInt16, UInt32, UInt64, UInt8]
@@ -173,9 +177,6 @@ parsehex(s) = parse(Int,s, base = 16)
 @test parse(Int, "3\u2003\u202F") == 3
 @test_throws ArgumentError parse(Int, "3\u2003\u202F,")
 
-@test parse(Int,'a') == 10
-@test_throws ArgumentError parse(Int,typemax(Char))
-
 @test parse(Int,"1234") == 1234
 @test parse(Int,"0x1234") == 0x1234
 @test parse(Int,"0o1234") == 0o1234