Rollup merge of #145747 - joshtriplett:builtin-diag-dyn, r=jdonszelmann

Refactor lint buffering to avoid requiring a giant enum

Lint buffering currently relies on a giant enum `BuiltinLintDiag` containing all the lints that might potentially get buffered. In addition to being an unwieldy enum in a central crate, this also makes `rustc_lint_defs` a build bottleneck: it depends on various types from various crates (with a steady pressure to add more), and many crates depend on it.

Having all of these variants in a separate crate also prevents detecting when a variant becomes unused, which we can do with a dedicated type defined and used in the same crate.

Refactor this to use a dyn trait, to allow using `LintDiagnostic` types directly.

Because the existing `BuiltinLintDiag` requires some additional types in order to decorate some variants, which are only available later in `rustc_lint`, use an enum `DecorateDiagCompat` to handle both the `dyn LintDiagnostic` case and the `BuiltinLintDiag` case.

---

With the infrastructure in place, use it to migrate three of the enum variants to use `LintDiagnostic` directly, as a proof of concept and to demonstrate that the net result is a reduction in code size and a removal of a boilerplate-heavy layer of indirection.

Also remove an unused `BuiltinLintDiag` variant.

1 files changed, 0 insertions, 25 deletions

diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl
index f26e5f05e1a..940a07c94df 100644
--- a/compiler/rustc_lint/messages.ftl
+++ b/compiler/rustc_lint/messages.ftl
@@ -205,8 +205,6 @@ lint_confusable_identifier_pair = found both `{$existing_sym}` and `{$sym}` as i
     .current_use = this identifier can be confused with `{$existing_sym}`
     .other_use = other identifier used here
 
-lint_custom_inner_attribute_unstable = custom inner attributes are unstable
-
 lint_dangling_pointers_from_locals = a dangling pointer will be produced because the local variable `{$local_var_name}` will be dropped
     .ret_ty = return type of the {$fn_kind} is `{$ret_ty}`
     .local_var = `{$local_var_name}` is part the {$fn_kind} and will be dropped at the end of the {$fn_kind}
@@ -271,10 +269,6 @@ lint_expectation = this lint expectation is unfulfilled
 lint_extern_crate_not_idiomatic = `extern crate` is not idiomatic in the new edition
     .suggestion = convert it to a `use`
 
-lint_extern_without_abi = `extern` declarations without an explicit ABI are deprecated
-    .label = ABI should be specified here
-    .suggestion = explicitly specify the {$default_abi} ABI
-
 lint_for_loops_over_fallibles =
     for loop over {$article} `{$ref_prefix}{$ty}`. This is more readably written as an `if let` statement
     .suggestion = consider using `if let` to clear intent
@@ -294,19 +288,6 @@ lint_hidden_glob_reexport = private item shadows public glob re-export
 
 lint_hidden_lifetime_parameters = hidden lifetime parameters in types are deprecated
 
-lint_hidden_unicode_codepoints = unicode codepoint changing visible direction of text present in {$label}
-    .label = this {$label} contains {$count ->
-        [one] an invisible
-        *[other] invisible
-    } unicode text flow control {$count ->
-        [one] codepoint
-        *[other] codepoints
-    }
-    .note = these kind of unicode codepoints change the way text flows on applications that support them, but can cause confusion because they change the order of characters on the screen
-    .suggestion_remove = if their presence wasn't intentional, you can remove them
-    .suggestion_escape = if you want to keep them but make them visible in your source code, you can escape them
-    .no_suggestion_note_escape = if you want to keep them but make them visible in your source code, you can escape them: {$escaped}
-
 lint_identifier_non_ascii_char = identifier contains non-ASCII characters
 
 lint_identifier_uncommon_codepoints = identifier contains {$codepoints_len ->
@@ -431,8 +412,6 @@ lint_improper_ctypes_union_non_exhaustive = this union is non-exhaustive
 lint_incomplete_include =
     include macro expected single expression in source
 
-lint_inner_macro_attribute_unstable = inner macro attributes are unstable
-
 lint_invalid_asm_label_binary = avoid using labels containing only the digits `0` and `1` in inline assembly
     .label = use a different label that doesn't start with `0` or `1`
     .help = start numbering with `2` instead
@@ -870,10 +849,6 @@ lint_undropped_manually_drops = calls to `std::mem::drop` with `std::mem::Manual
     .label = argument has type `{$arg_ty}`
     .suggestion = use `std::mem::ManuallyDrop::into_inner` to get the inner value
 
-lint_unexpected_builtin_cfg = unexpected `--cfg {$cfg}` flag
-    .controlled_by = config `{$cfg_name}` is only supposed to be controlled by `{$controlled_by}`
-    .incoherent = manually setting a built-in cfg can and does create incoherent behaviors
-
 lint_unexpected_cfg_add_build_rs_println = or consider adding `{$build_rs_println}` to the top of the `build.rs`
 lint_unexpected_cfg_add_cargo_feature = consider using a Cargo feature instead
 lint_unexpected_cfg_add_cargo_toml_lint_cfg = or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:{$cargo_toml_lint_cfg}