• via Digitalmars-d-bugs (65/65) Aug 25 2015 https://issues.dlang.org/show_bug.cgi?id=14962

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=14962

          Issue ID: 14962
           Summary: [REG2.068] compiler inference of attributes for nested
                    map seems broken
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: rejects-valid
          Severity: regression
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: schveiguy yahoo.com

Not sure if these are related, but they seem similar:

import std.algorithm;

struct Foo {
    int baz(int v) {
        static int id;
        return v + id++;
    }
    void bar() {
        auto arr1 = [1, 2, 3];
        auto arr2 = [4, 5, 6];
        arr1.map!(i =>
                  arr2.map!(j => baz(i + j))
                 );
    }
}

void main() {
} 

testfoo.d(12): Error: pure function
'testfoo.Foo.bar.__lambda1!int.__lambda1.__lambda2' cannot call impure function
'testfoo.Foo.baz'
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(459):
       instantiated from here: MapResult!(__lambda2, int[])
testfoo.d(12):        instantiated from here: map!(int[])
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(549):
       instantiated from here: __lambda1!int
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(459):
       instantiated from here: MapResult!(__lambda1, int[])
testfoo.d(11):        instantiated from here: map!(int[])

Another case:

import std.range;
import std.algorithm;

class Foo {
    int baz() {    return 1;}
    void bar() {
        auto s = [1].map!(i => baz()); // compiles
        auto r = [1].map!(i => [1].map!(j => baz())); // error
    }
}

testfoo.d(8): Error: need 'this' for 'baz' of type 'int()'
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(459):
       instantiated from here: MapResult!(__lambda2, int[])
testfoo.d(8):        instantiated from here: map!(int[])
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(549):
       instantiated from here: __lambda2!int
/Users/steves/git/dmd2/osx/bin/../../src/phobos/std/algorithm/iteration.d(459):
       instantiated from here: MapResult!(__lambda2, int[])
testfoo.d(8):        instantiated from here: map!(int[])

I'm going to file this as a dmd issue, because it seems like it's a case of
attribute inference for the lambdas, not an issue with map.

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