Fix HIR printing of parameters #138482
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Fix HIR printing of parameters #138482
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Note that multiple parts of the output are incorrect. The following commits will fix this.
It has a single call site.
Currently (PatKind::Wild` (i.e. `_`) gets turned by `lower_fn_params_to_names` into an empty identifier, which means it is printed incorrectly by HIR pretty printing. And likewise for `lower_fn_params_to_names`, which affects some error messages. This commit fixes them. This requires a slight tweak in a couple of places to continue using parameter numbers in some error messages. And it improves the output of `tests/ui/typeck/cyclic_type_ice.rs`: `/* _ */` is a better suggestion than `/* */`.
Anonymous params are currently represented with `kw::Empty`, so handle that properly. (Subsequent commits will get rid of the `kw::Empty`.)
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Best reviewed one commit at a time. I found these issues while looking at |
compiler-errors
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r? compiler-errors @bors r+ rollup |
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fmease
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…mpiler-errors Fix HIR printing of parameters HIR pretty printing does the wrong thing for anonymous parameters, and there is no test coverage for it. This PR remedies both of those things. r? `@lcnr`
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Rollup of 8 pull requests Successful merges: - rust-lang#138056 (rustc_target: Add target features for LoongArch v1.1) - rust-lang#138349 (Emit function declarations for functions with `#[linkage="extern_weak"]`) - rust-lang#138451 (Build GCC on CI with GCC, not Clang) - rust-lang#138454 (Improve post-merge workflow) - rust-lang#138460 (Pass struct field HirId when check_expr_struct_fields) - rust-lang#138482 (Fix HIR printing of parameters) - rust-lang#138507 (Mirror NetBSD sources) - rust-lang#138511 (Make `Parser::parse_expr_cond` public) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 9 pull requests Successful merges: - rust-lang#138056 (rustc_target: Add target features for LoongArch v1.1) - rust-lang#138451 (Build GCC on CI with GCC, not Clang) - rust-lang#138454 (Improve post-merge workflow) - rust-lang#138460 (Pass struct field HirId when check_expr_struct_fields) - rust-lang#138474 (Refactor is_snake_case.) - rust-lang#138482 (Fix HIR printing of parameters) - rust-lang#138507 (Mirror NetBSD sources) - rust-lang#138511 (Make `Parser::parse_expr_cond` public) - rust-lang#138518 (Fix typo in hir lowering lint diag) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#138482 - nnethercote:fix-hir-printing, r=compiler-errors Fix HIR printing of parameters HIR pretty printing does the wrong thing for anonymous parameters, and there is no test coverage for it. This PR remedies both of those things. r? ``@lcnr``
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Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing.
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Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing.
jieyouxu
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…owered-param-names, r=compiler-errors Use `Option<Ident>` for lowered param names. Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing. r? `@compiler-errors`
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…owered-param-names, r=compiler-errors Use `Option<Ident>` for lowered param names. Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing. r? ``@compiler-errors``
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…owered-param-names, r=compiler-errors Use `Option<Ident>` for lowered param names. Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing. r? ```@compiler-errors```
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Mar 21, 2025
Rollup merge of rust-lang#138685 - nnethercote:use-Option-Ident-for-lowered-param-names, r=compiler-errors Use `Option<Ident>` for lowered param names. Parameter patterns are lowered to an `Ident` by `lower_fn_params_to_names`, which is used when lowering bare function types, trait methods, and foreign functions. Currently, there are two exceptional cases where the lowered param can become an empty `Ident`. - If the incoming pattern is an empty `Ident`. This occurs if the parameter is anonymous, e.g. in a bare function type. - If the incoming pattern is neither an ident nor an underscore. Any such parameter will have triggered a compile error (hence the `span_delayed_bug`), but lowering still occurs. This commit replaces these empty `Ident` results with `None`, which eliminates a number of `kw::Empty` uses, and makes it impossible to fail to check for these exceptional cases. Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It actually should have been removed in rust-lang#138482, the precursor to this PR. That PR changed the lowering of wild patterns to `_` symbols instead of empty symbols, which made the mentioned underscore check load-bearing. r? ``@compiler-errors``
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HIR pretty printing does the wrong thing for anonymous parameters, and there is no test coverage for it. This PR remedies both of those things.
r? @lcnr