GLSL spec 5.4.2 says about vector constructor:
It is an error to provide extra arguments beyond this last used argument.
But mesa passes for:
vec4 v1 = vec4(v,v,v);
vec4 v1 = vec4(i,i,i,i,i);
This impacts tests/glslparsertest/shaders/constructor3.V110.frag (though I don't understand why it uses "V110" -- the is defined through V110 to V150)
Fixed with glsl2 merge.
verified with mesa master d442a01ac14382d83cdaac87d2832315ceb3e963.