compiler: remove anonymous struct types, unify all tuples #21817
+961
−1,210
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This commit reworks how anonymous struct literals and tuples work.
Previously, an untyped anonymous struct literal (e.g.
const x = .{ .a = 123 }
) was given an "anonymous struct type", which is a special kind of struct which coerces using structural equivalence. This mechanism was a holdover from before we used RLS / result types as the primary mechanism of type inference. This commit changes the language so that the type assigned here is a "normal" struct type. It uses a form of equivalence based on the AST node and the type's structure, much like a reified (@Type
) type.Additionally, tuples have been simplified. The distinction between "simple" and "complex" tuple types is eliminated. All tuples, even those explicitly declared using
struct { ... }
syntax, use structural equivalence, and do not undergo staged type resolution. Tuples are very restricted: they cannot have non-auto
layouts, cannot have aligned fields, and cannot have default values with the exception ofcomptime
fields. Tuples currently do not have optimized layout, but this can be changed in the future.This change simplifies the language, and fixes some problematic coercions through pointers which led to unintuitive behavior.
Resolves: #16865