Module rustc_passes::check_const

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This pass checks HIR bodies that may be evaluated at compile-time (e.g., const, static, const fn) for structured control flow (e.g. if, while), which is forbidden in a const context.

By the time the MIR const-checker runs, these high-level constructs have been lowered to control-flow primitives (e.g., Goto, SwitchInt), making it tough to properly attribute errors. We still look for those primitives in the MIR const-checker to ensure nothing slips through, but errors for structured control flow in a const should be emitted here.



  • NonConstExpr ๐Ÿ”’
    An expression that is not always legal in a const context.