[Issue 11444] New: Better error messages for Phobos ranges used without bang !

[d-bugmail at puremagic.com]

https://d.puremagic.com/issues/show_bug.cgi?id=11444

           Summary: Better error messages for Phobos ranges used without
                    bang !
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: diagnostic
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: bearophile_hugs at eml.cc


--- Comment #0 from bearophile_hugs at eml.cc 2013-11-05 07:39:06 PST ---
This is wrong code:


import std.stdio, std.algorithm;
void main() {
    "123".map(d => d - '0').writeln;
}


dmd 2.064beta gives the error messages:

test.d(3): Error: template std.algorithm.map does not match any function
template declaration. Candidates are:
...\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(398):       
std.algorithm.map(fun...) if (fun.length >= 1)
test.d(3): Error: template std.algorithm.map(fun...) if (fun.length >= 1)
cannot deduce template function from argument types !()(string, void)


The mistake is in the map, it should be "map!(...)". Range-based code that uses
map, filter and other similar functions is becoming common, so I suggest to add
some euristics to the D front-end to generate better error messages for common
Phobos templates that are used without the "!", something like:

test.d(3): Error: template std.algorithm.map does not match any function
template. Did you miss a "!"?

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