Auto merge of rust-lang#6086 - Ryan1729:add-suspicious_chained_operators-lint, r=llogiq

Add suspicious_operation_groupings lint

This is my (<del> currently WIP </del>) attempt to close rust-lang#6039.

changelog: Added `suspicious_operation_groupings` lint.

Author: bors

CHANGELOG.md

@@ -2073,6 +2073,7 @@ Released 2018-09-13
 [`suspicious_else_formatting`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_else_formatting
 [`suspicious_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_map
 [`suspicious_op_assign_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_op_assign_impl
+[`suspicious_operation_groupings`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_operation_groupings
 [`suspicious_unary_op_formatting`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_unary_op_formatting
 [`tabs_in_doc_comments`]: https://rust-lang.github.io/rust-clippy/master/index.html#tabs_in_doc_comments
 [`temporary_assignment`]: https://rust-lang.github.io/rust-clippy/master/index.html#temporary_assignment

clippy_lints/src/eq_op.rs

@@ -1,10 +1,10 @@
 use crate::utils::{
-    eq_expr_value, higher, implements_trait, in_macro, is_copy, is_expn_of, multispan_sugg, snippet, span_lint,
-    span_lint_and_then,
+    ast_utils::is_useless_with_eq_exprs, eq_expr_value, higher, implements_trait, in_macro, is_copy, is_expn_of,
+    multispan_sugg, snippet, span_lint, span_lint_and_then,
 };
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{BinOp, BinOpKind, BorrowKind, Expr, ExprKind, StmtKind};
+use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
@@ -102,7 +102,7 @@ impl<'tcx> LateLintPass<'tcx> for EqOp {
             if macro_with_not_op(&left.kind) || macro_with_not_op(&right.kind) {
                 return;
             }
-            if is_valid_operator(op) && eq_expr_value(cx, left, right) {
+            if is_useless_with_eq_exprs(higher::binop(op.node)) && eq_expr_value(cx, left, right) {
                 span_lint(
                     cx,
                     EQ_OP,
@@ -245,22 +245,3 @@ impl<'tcx> LateLintPass<'tcx> for EqOp {
         }
     }
 }
-
-fn is_valid_operator(op: BinOp) -> bool {
-    matches!(
-        op.node,
-        BinOpKind::Sub
-            | BinOpKind::Div
-            | BinOpKind::Eq
-            | BinOpKind::Lt
-            | BinOpKind::Le
-            | BinOpKind::Gt
-            | BinOpKind::Ge
-            | BinOpKind::Ne
-            | BinOpKind::And
-            | BinOpKind::Or
-            | BinOpKind::BitXor
-            | BinOpKind::BitAnd
-            | BinOpKind::BitOr
-    )
-}

clippy_lints/src/lib.rs

@@ -308,6 +308,7 @@ mod single_component_path_imports;
 mod slow_vector_initialization;
 mod stable_sort_primitive;
 mod strings;
+mod suspicious_operation_groupings;
 mod suspicious_trait_impl;
 mod swap;
 mod tabs_in_doc_comments;
@@ -834,6 +835,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &strings::STRING_LIT_AS_BYTES,
         &strings::STRING_TO_STRING,
         &strings::STR_TO_STRING,
+        &suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS,
         &suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL,
         &suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL,
         &swap::ALMOST_SWAPPED,
@@ -1066,6 +1068,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| box types::UnitArg);
     store.register_late_pass(|| box double_comparison::DoubleComparisons);
     store.register_late_pass(|| box question_mark::QuestionMark);
+    store.register_early_pass(|| box suspicious_operation_groupings::SuspiciousOperationGroupings);
     store.register_late_pass(|| box suspicious_trait_impl::SuspiciousImpl);
     store.register_late_pass(|| box map_unit_fn::MapUnit);
     store.register_late_pass(|| box inherent_impl::MultipleInherentImpl::default());
@@ -1547,6 +1550,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&slow_vector_initialization::SLOW_VECTOR_INITIALIZATION),
         LintId::of(&stable_sort_primitive::STABLE_SORT_PRIMITIVE),
         LintId::of(&strings::STRING_FROM_UTF8_AS_BYTES),
+        LintId::of(&suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
         LintId::of(&suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL),
         LintId::of(&suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),
         LintId::of(&swap::ALMOST_SWAPPED),
@@ -1698,6 +1702,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&returns::LET_AND_RETURN),
         LintId::of(&returns::NEEDLESS_RETURN),
         LintId::of(&single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
+        LintId::of(&suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
         LintId::of(&tabs_in_doc_comments::TABS_IN_DOC_COMMENTS),
         LintId::of(&to_digit_is_some::TO_DIGIT_IS_SOME),
         LintId::of(&try_err::TRY_ERR),