Catalyzes the attachment of valine to tRNA(Val). As ValRS can inadvertently accommodate and process structurally similar amino acids such as threonine, to avoid such errors, it has a 'posttransfer' editing activity that hydrolyzes mischarged Thr-tRNA(Val) in a tRNA-dependent manner. ATP + L-valine + tRNA(Val) = AMP + diphosphate + L-valyl-tRNA(Val) ValRS has two distinct active sites: one for aminoacylation and one for editing. The misactivated threonine is translocated from the active site to the editing site. Belongs to the class-I aminoacyl-tRNA synthetase family. ValS type 2 subfamily.