The following code compiles and runs fine with DMD 2.057, but fails on DMD 2.058head with Internal error: toir.c 178 // import std.stdio, std.algorithm, std.range; auto Y(R,T...)(R delegate(T) delegate (R delegate(T)) f){ struct F{R delegate(F,T) f;}; return (R delegate(T)delegate(F) a){return a(F((F b,T i){return f(a(b))(i);})); }((F b){return (T n){return b.f(b,n);};}); } void main(){ auto factorial=Y((long delegate(long) self){return (long i){return i?self(i-1)*i:1;};}); auto fibonacci=Y((int delegate(int) self){return (int i){return i<2?i:self(i-1)+self(i-2);};}); auto ackermann=Y((long delegate(long,long) self){return (long n,long m){return n?m?self(n-1,self(n,m-1)):self(n-1,1):m+1;};}); // writeln(map!factorial(iota(0,20))); // writeln(map!fibonacci(iota(0,20))); // writeln(map!((a){return ackermann(a%4,a/4);})(iota(0,20))); }
I simplified this a bit (still hurts my brain, though). The bug is tripped when a lambda is used rather than the equivalent nested function: alias long delegate(long) dg_t; void Y(dg_t delegate (dg_t) y) { struct F { long delegate(F) f; }; version (all) { // generates error (dg_t delegate(F) a){return a(F((F b){return y(a(b))(1);})); } ((F b){return (long n){return b.f(b);};}); } else { auto abc(dg_t delegate(F) a) { return a(F((F b){return y(a(b))(1);})); } abc((F b){return (long n){return b.f(b);};}); } } void main(){ auto foo(dg_t self) { auto bar(long i) { return self(1); } return &bar; } Y(&foo); }
Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/8b8abab85a916153211c902aa41b23786cda6062 fix Issue 7428 - regression (DMD 2.058head) ICE on slightly convoluted setup including closures