\documentclass{article}

\usepackage{agda}

\begin{document}

No indentation should be inserted before \AgdaKeyword{postulate} or
the last occurrence of \AgdaPrimitiveType{Set}, and the last
occurrence of \AgdaPrimitiveType{Set} should be aligned with the
penultimate occurrence of \AgdaPrimitiveType{Set}:
\begin{code}%
%
\>[2]\AgdaKeyword{postulate}\<%
\\
\>[2][@{}l@{\AgdaIndent{0}}]%
\>[4]\AgdaPostulate{A}%
\>[7]\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitiveType{Set}\<%
\\
%
\>[4]\AgdaPostulate{B}%
\>[7]\AgdaSymbol{:}%
\>[1I]\AgdaPrimitiveType{Set}\AgdaSpace{}%
\AgdaSymbol{→}\<%
\\
\>[.][@{}l@{}]\<[1I]%
\>[9]\AgdaPrimitiveType{Set}\<%
\end{code}

\end{document}
