rust: build: establish a baseline of lints across all crates

Many lints that default to allow can be helpful in detecting bugs or
keeping the code style homogeneous.  Add them liberally, though perhaps
not as liberally as in hw/char/pl011/src/lib.rs.  In particular, enabling
entire groups can be problematic because of bitrot when new links are
added in the future.

For Clippy, this is actually a feature that is only present in Cargo
1.74.0 but, since we are not using Cargo to *build* QEMU, only developers
will need a new-enough cargo and only to run tools such as clippy.
The requirement does not apply to distros that are building QEMU.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 74 insertions, 19 deletions

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 358c517..6ec19b67 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -19,3 +19,71 @@ unknown_lints = "allow"
 
 # Prohibit code that is forbidden in Rust 2024
 unsafe_op_in_unsafe_fn = "deny"
+
+[workspace.lints.rustdoc]
+private_intra_doc_links = "allow"
+
+broken_intra_doc_links = "deny"
+invalid_html_tags = "deny"
+invalid_rust_codeblocks = "deny"
+bare_urls = "deny"
+unescaped_backticks = "deny"
+redundant_explicit_links = "deny"
+
+[workspace.lints.clippy]
+# default-warn lints
+result_unit_err = "allow"
+should_implement_trait = "deny"
+# can be for a reason, e.g. in callbacks
+unused_self = "allow"
+
+# default-allow lints
+as_underscore = "deny"
+assertions_on_result_states = "deny"
+bool_to_int_with_if = "deny"
+borrow_as_ptr = "deny"
+cast_lossless = "deny"
+dbg_macro = "deny"
+debug_assert_with_mut_call = "deny"
+derive_partial_eq_without_eq = "deny"
+doc_markdown = "deny"
+empty_structs_with_brackets = "deny"
+ignored_unit_patterns = "deny"
+implicit_clone = "deny"
+macro_use_imports = "deny"
+missing_const_for_fn = "deny"
+missing_safety_doc = "deny"
+multiple_crate_versions = "deny"
+mut_mut = "deny"
+needless_bitwise_bool = "deny"
+needless_pass_by_ref_mut = "deny"
+no_effect_underscore_binding = "deny"
+option_option = "deny"
+or_fun_call = "deny"
+ptr_as_ptr = "deny"
+pub_underscore_fields = "deny"
+redundant_clone = "deny"
+redundant_closure_for_method_calls = "deny"
+redundant_else = "deny"
+redundant_pub_crate = "deny"
+ref_binding_to_reference = "deny"
+ref_option_ref = "deny"
+return_self_not_must_use = "deny"
+same_name_method = "deny"
+semicolon_inside_block = "deny"
+shadow_unrelated = "deny"
+significant_drop_in_scrutinee = "deny"
+significant_drop_tightening = "deny"
+suspicious_operation_groupings = "deny"
+transmute_ptr_to_ptr = "deny"
+transmute_undefined_repr = "deny"
+type_repetition_in_bounds = "deny"
+used_underscore_binding = "deny"
+
+# nice to have, but cannot be enabled yet
+#wildcard_imports = "deny"   # still have many bindings::* imports
+#ptr_cast_constness = "deny" # needs 1.65.0 for cast_mut()/cast_const()
+
+# these may have false positives
+#option_if_let_else = "deny"
+cognitive_complexity = "deny"
diff --git a/rust/hw/char/pl011/src/lib.rs b/rust/hw/char/pl011/src/lib.rs
index cd0a49a..4dc0e8f 100644
--- a/rust/hw/char/pl011/src/lib.rs
+++ b/rust/hw/char/pl011/src/lib.rs
@@ -14,28 +14,15 @@
 //! the [`registers`] module for register types.
 
 #![deny(
-    rustdoc::broken_intra_doc_links,
-    rustdoc::redundant_explicit_links,
     clippy::correctness,
     clippy::suspicious,
     clippy::complexity,
     clippy::perf,
     clippy::cargo,
     clippy::nursery,
-    clippy::style,
-    // restriction group
-    clippy::dbg_macro,
-    clippy::as_underscore,
-    clippy::assertions_on_result_states,
-    // pedantic group
-    clippy::doc_markdown,
-    clippy::borrow_as_ptr,
-    clippy::cast_lossless,
-    clippy::option_if_let_else,
-    clippy::missing_const_for_fn,
-    clippy::cognitive_complexity,
-    clippy::missing_safety_doc,
-    )]
+    clippy::style
+)]
+#![allow(clippy::upper_case_acronyms)]
 #![allow(clippy::result_unit_err)]
 
 extern crate bilge;
diff --git a/rust/qemu-api/src/bindings.rs b/rust/qemu-api/src/bindings.rs
index 0b76ec5..8a9b821 100644
--- a/rust/qemu-api/src/bindings.rs
+++ b/rust/qemu-api/src/bindings.rs
@@ -7,10 +7,10 @@
     non_snake_case,
     non_upper_case_globals,
     unsafe_op_in_unsafe_fn,
+    clippy::pedantic,
+    clippy::restriction,
+    clippy::style,
     clippy::missing_const_for_fn,
-    clippy::too_many_arguments,
-    clippy::approx_constant,
-    clippy::use_self,
     clippy::useless_transmute,
     clippy::missing_safety_doc
 )]