Downgrade useless_let_if_seq to nursery

Author: dtolnay

clippy_lints/src/let_if_seq.rs

@@ -50,7 +50,7 @@ declare_clippy_lint! {
     /// };
     /// ```
     pub USELESS_LET_IF_SEQ,
-    style,
+    nursery,
     "unidiomatic `let mut` declaration followed by initialization in `if`"
 }
 

clippy_lints/src/lib.rs

@@ -1266,7 +1266,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&large_enum_variant::LARGE_ENUM_VARIANT),
         LintId::of(&len_zero::LEN_WITHOUT_IS_EMPTY),
         LintId::of(&len_zero::LEN_ZERO),
-        LintId::of(&let_if_seq::USELESS_LET_IF_SEQ),
         LintId::of(&let_underscore::LET_UNDERSCORE_LOCK),
         LintId::of(&lifetimes::EXTRA_UNUSED_LIFETIMES),
         LintId::of(&lifetimes::NEEDLESS_LIFETIMES),
@@ -1476,7 +1475,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&inherent_to_string::INHERENT_TO_STRING),
         LintId::of(&len_zero::LEN_WITHOUT_IS_EMPTY),
         LintId::of(&len_zero::LEN_ZERO),
-        LintId::of(&let_if_seq::USELESS_LET_IF_SEQ),
         LintId::of(&literal_representation::INCONSISTENT_DIGIT_GROUPING),
         LintId::of(&loops::EMPTY_LOOP),
         LintId::of(&loops::FOR_KV_MAP),
@@ -1728,6 +1726,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&floating_point_arithmetic::IMPRECISE_FLOPS),
         LintId::of(&floating_point_arithmetic::SUBOPTIMAL_FLOPS),
         LintId::of(&future_not_send::FUTURE_NOT_SEND),
+        LintId::of(&let_if_seq::USELESS_LET_IF_SEQ),
         LintId::of(&missing_const_for_fn::MISSING_CONST_FOR_FN),
         LintId::of(&mutable_debug_assertion::DEBUG_ASSERT_WITH_MUT_CALL),
         LintId::of(&mutex_atomic::MUTEX_INTEGER),

src/lintlist/mod.rs

@@ -2469,7 +2469,7 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
     },
     Lint {
         name: "useless_let_if_seq",
-        group: "style",
+        group: "nursery",
         desc: "unidiomatic `let mut` declaration followed by initialization in `if`",
         deprecation: None,
         module: "let_if_seq",