Fix crash when unable to infer generic type arguments
Fix crash when unable to infer generic type arguments

playya/vala,themiwi/vala,frida/vala,rvu95/vala,kamanashisroy/aroop,frida/vala,flobrosch/vala-fixes,rvu95/vala,spidermonkdust/vala,GNOME/vala,kamanashisroy/aroop,severinh/vala,frida/vala,GNOME/vala,tjol/vala-tjol,tjol/vala-tjol,jessevdk/vala,severinh/vala,tjol/vala-tjol,playya/vala,jessevdk/vala,spidermonkdust/vala,kamanashisroy/aroop,themiwi/vala,playya/vala,Distrotech/vala,frida/vala,jessevdk/vala,flobrosch/vala-fixes,GNOME/vala,severinh/vala,xdave/pvala,themiwi/vala,frida/vala,rvu95/vala,GNOME/vala,Distrotech/vala,flobrosch/vala-fixes,spidermonkdust/vala,Distrotech/vala