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Zig / Comptime

@hasDecl

Learn @hasDecl in Zig with a construct-specific explanation, unique example, engineering boundary, and mastery check.

10 min read • Advanced

@hasDecl is a focused Zig topic inside Comptime. This lesson explains the construct itself, the state or value it operates on, and the observable result it produces.

Read the example as a small executable experiment. Identify the exact syntax that belongs to @hasDecl, then change one input and predict the result before running it.

Topic-specific example

zig-07-05-hasdecl.zig
zig Try It Live 
comptime { if (@hasDecl(std,"debug")) {} }
Edge case / engineering note

@hasDecl has rules that are easy to miss when the example is copied mechanically. Check the feature-specific boundary shown by this construct: scope, mutability, evaluation order, type constraints, lifetime, error behavior, compile-time restrictions, or resource cleanup where applicable.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

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