diff -up vim74/runtime/syntax/yaml.vim.yamlsyntax vim74/runtime/syntax/yaml.vim

--- vim74/runtime/syntax/yaml.vim.yamlsyntax	2016-11-25 13:08:38.621772847 +0100

+++ vim74/runtime/syntax/yaml.vim	2016-11-25 15:04:38.170017620 +0100

@@ -103,14 +103,15 @@ execute 'syn match yamlPlainScalar conta

 syn match yamlMappingKeyStart '?\ze\s'

 syn match yamlMappingKeyStart '?' contained

-execute 'syn match yamlFlowMappingKey /'.s:ns_plain_in.'\ze\s*:/ contained '.

+execute 'syn match yamlFlowMappingKey /\%#=1'.s:ns_plain_in.'\%(\s\+'.s:ns_plain_in.'\)*\ze\s*:/ contained '.

             \'nextgroup=yamlKeyValueDelimiter'

 syn match yamlFlowMappingMerge /<<\ze\s*:/ contained nextgroup=yamlKeyValueDelimiter

 syn match yamlBlockCollectionItemStart '^\s*\zs-\%(\s\+-\)*\s' nextgroup=yamlBlockMappingKey,yamlBlockMappingMerge

-execute 'syn match yamlBlockMappingKey /^\s*\zs'.s:ns_plain_out.'\ze\s*:\%(\s\|$\)/ '.

+" Use the old regexp engine, the NFA engine doesn't like all the \@ items.

+execute 'syn match yamlBlockMappingKey /\%#=1^\s*\zs'.s:ns_plain_out.'\%(\s\+'.s:ns_plain_out.'\)*\ze\s*:\%(\s\|$\)/ '.

             \'nextgroup=yamlKeyValueDelimiter'

-execute 'syn match yamlBlockMappingKey /\s*\zs'.s:ns_plain_out.'\ze\s*:\%(\s\|$\)/ contained '.

+execute 'syn match yamlBlockMappingKey /\%#=1\s*\zs'.s:ns_plain_out.'\%(\s\+'.s:ns_plain_out.'\)*\ze\s*:\%(\s\|$\)/ contained '.

             \'nextgroup=yamlKeyValueDelimiter'

 syn match yamlBlockMappingMerge /^\s*\zs<<\ze:\%(\s\|$\)/ nextgroup=yamlKeyValueDelimiter

 syn match yamlBlockMappingMerge /<<\ze\s*:\%(\s\|$\)/ nextgroup=yamlKeyValueDelimiter contained