Auto merge of #4839 - flip1995:rollup-new-lints, r=flip1995

Rollup of 4 Pull requests with new lints

Rollup of pull requests

- #4816 (New lint: zst_offset)
- #4814 (New lint: Implement ifs_same_cond_fn)
- #4807 (Add `large_stack_arrays` lint)
- #4806 (Issue/4623)

changelog: add [`zst_offset`] lint
changelog: New lint: [`ifs_same_cond_fn`]
cahngelog: Add new lint [large_stack_arrays]
changelog: added lint [`tabs_in_doc_comments`]

CHANGELOG.md

@@ -1059,6 +1059,7 @@ Released 2018-09-13
 [`just_underscores_and_digits`]: https://rust-lang.github.io/rust-clippy/master/index.html#just_underscores_and_digits
 [`large_digit_groups`]: https://rust-lang.github.io/rust-clippy/master/index.html#large_digit_groups
 [`large_enum_variant`]: https://rust-lang.github.io/rust-clippy/master/index.html#large_enum_variant
+[`large_stack_arrays`]: https://rust-lang.github.io/rust-clippy/master/index.html#large_stack_arrays
 [`len_without_is_empty`]: https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty
 [`len_zero`]: https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
 [`let_and_return`]: https://rust-lang.github.io/rust-clippy/master/index.html#let_and_return
@@ -1176,6 +1177,7 @@ Released 2018-09-13
 [`result_map_unwrap_or_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_unwrap_or_else
 [`result_unwrap_used`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_unwrap_used
 [`reverse_range_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#reverse_range_loop
+[`same_functions_in_if_condition`]: https://rust-lang.github.io/rust-clippy/master/index.html#same_functions_in_if_condition
 [`search_is_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#search_is_some
 [`serde_api_misuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#serde_api_misuse
 [`shadow_reuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#shadow_reuse
@@ -1201,6 +1203,7 @@ Released 2018-09-13
 [`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_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
 [`temporary_cstring_as_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#temporary_cstring_as_ptr
 [`to_digit_is_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#to_digit_is_some
@@ -1273,4 +1276,5 @@ Released 2018-09-13
 [`zero_prefixed_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_prefixed_literal
 [`zero_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_ptr
 [`zero_width_space`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_width_space
+[`zst_offset`]: https://rust-lang.github.io/rust-clippy/master/index.html#zst_offset
 <!-- end autogenerated links to lint list -->

README.md

@@ -6,7 +6,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 333 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are 337 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

clippy_lints/src/copies.rs

@@ -40,6 +40,53 @@ declare_clippy_lint! {
     "consecutive `ifs` with the same condition"
 }
 
+declare_clippy_lint! {
+    /// **What it does:** Checks for consecutive `if`s with the same function call.
+    ///
+    /// **Why is this bad?** This is probably a copy & paste error.
+    /// Despite the fact that function can have side effects and `if` works as
+    /// intended, such an approach is implicit and can be considered a "code smell".
+    ///
+    /// **Known problems:** Hopefully none.
+    ///
+    /// **Example:**
+    /// ```ignore
+    /// if foo() == bar {
+    ///     …
+    /// } else if foo() == bar {
+    ///     …
+    /// }
+    /// ```
+    ///
+    /// This probably should be:
+    /// ```ignore
+    /// if foo() == bar {
+    ///     …
+    /// } else if foo() == baz {
+    ///     …
+    /// }
+    /// ```
+    ///
+    /// or if the original code was not a typo and called function mutates a state,
+    /// consider move the mutation out of the `if` condition to avoid similarity to
+    /// a copy & paste error:
+    ///
+    /// ```ignore
+    /// let first = foo();
+    /// if first == bar {
+    ///     …
+    /// } else {
+    ///     let second = foo();
+    ///     if second == bar {
+    ///     …
+    ///     }
+    /// }
+    /// ```
+    pub SAME_FUNCTIONS_IN_IF_CONDITION,
+    pedantic,
+    "consecutive `ifs` with the same function call"
+}
+
 declare_clippy_lint! {
     /// **What it does:** Checks for `if/else` with the same body as the *then* part
     /// and the *else* part.
@@ -102,7 +149,7 @@ declare_clippy_lint! {
     "`match` with identical arm bodies"
 }
 
-declare_lint_pass!(CopyAndPaste => [IFS_SAME_COND, IF_SAME_THEN_ELSE, MATCH_SAME_ARMS]);
+declare_lint_pass!(CopyAndPaste => [IFS_SAME_COND, SAME_FUNCTIONS_IN_IF_CONDITION, IF_SAME_THEN_ELSE, MATCH_SAME_ARMS]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CopyAndPaste {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
@@ -119,6 +166,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CopyAndPaste {
             let (conds, blocks) = if_sequence(expr);
             lint_same_then_else(cx, &blocks);
             lint_same_cond(cx, &conds);
+            lint_same_fns_in_if_cond(cx, &conds);
             lint_match_arms(cx, expr);
         }
     }
@@ -163,6 +211,34 @@ fn lint_same_cond(cx: &LateContext<'_, '_>, conds: &[&Expr]) {
     }
 }
 
+/// Implementation of `SAME_FUNCTIONS_IN_IF_CONDITION`.
+fn lint_same_fns_in_if_cond(cx: &LateContext<'_, '_>, conds: &[&Expr]) {
+    let hash: &dyn Fn(&&Expr) -> u64 = &|expr| -> u64 {
+        let mut h = SpanlessHash::new(cx, cx.tables);
+        h.hash_expr(expr);
+        h.finish()
+    };
+
+    let eq: &dyn Fn(&&Expr, &&Expr) -> bool = &|&lhs, &rhs| -> bool {
+        // Do not spawn warning if `IFS_SAME_COND` already produced it.
+        if SpanlessEq::new(cx).ignore_fn().eq_expr(lhs, rhs) {
+            return false;
+        }
+        SpanlessEq::new(cx).eq_expr(lhs, rhs)
+    };
+
+    for (i, j) in search_same(conds, hash, eq) {
+        span_note_and_lint(
+            cx,
+            SAME_FUNCTIONS_IN_IF_CONDITION,
+            j.span,
+            "this `if` has the same function call as a previous if",
+            i.span,
+            "same as this",
+        );
+    }
+}
+
 /// Implementation of `MATCH_SAME_ARMS`.
 fn lint_match_arms<'tcx>(cx: &LateContext<'_, 'tcx>, expr: &Expr) {
     fn same_bindings<'tcx>(

clippy_lints/src/large_stack_arrays.rs

@@ -0,0 +1,68 @@
+use rustc::hir::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::mir::interpret::ConstValue;
+use rustc::ty::{self, ConstKind};
+use rustc::{declare_tool_lint, impl_lint_pass};
+
+use if_chain::if_chain;
+
+use crate::rustc_target::abi::LayoutOf;
+use crate::utils::{snippet, span_help_and_lint};
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for local arrays that may be too large.
+    ///
+    /// **Why is this bad?** Large local arrays may cause stack overflow.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust,ignore
+    /// let a = [0u32; 1_000_000];
+    /// ```
+    pub LARGE_STACK_ARRAYS,
+    pedantic,
+    "allocating large arrays on stack may cause stack overflow"
+}
+
+pub struct LargeStackArrays {
+    maximum_allowed_size: u64,
+}
+
+impl LargeStackArrays {
+    #[must_use]
+    pub fn new(maximum_allowed_size: u64) -> Self {
+        Self { maximum_allowed_size }
+    }
+}
+
+impl_lint_pass!(LargeStackArrays => [LARGE_STACK_ARRAYS]);
+
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LargeStackArrays {
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &Expr) {
+        if_chain! {
+            if let ExprKind::Repeat(_, _) = expr.kind;
+            if let ty::Array(element_type, cst) = cx.tables.expr_ty(expr).kind;
+            if let ConstKind::Value(val) = cst.val;
+            if let ConstValue::Scalar(element_count) = val;
+            if let Ok(element_count) = element_count.to_machine_usize(&cx.tcx);
+            if let Ok(element_size) = cx.layout_of(element_type).map(|l| l.size.bytes());
+            if self.maximum_allowed_size < element_count * element_size;
+            then {
+                span_help_and_lint(
+                    cx,
+                    LARGE_STACK_ARRAYS,
+                    expr.span,
+                    &format!(
+                        "allocating a local array larger than {} bytes",
+                        self.maximum_allowed_size
+                    ),
+                    &format!(
+                        "consider allocating on the heap with vec!{}.into_boxed_slice()",
+                        snippet(cx, expr.span, "[...]")
+                    ),
+                );
+            }
+        }
+    }
+}

clippy_lints/src/lib.rs

@@ -212,6 +212,7 @@ pub mod int_plus_one;
 pub mod integer_division;
 pub mod items_after_statements;
 pub mod large_enum_variant;
+pub mod large_stack_arrays;
 pub mod len_zero;
 pub mod let_if_seq;
 pub mod lifetimes;
@@ -274,6 +275,7 @@ pub mod slow_vector_initialization;
 pub mod strings;
 pub mod suspicious_trait_impl;
 pub mod swap;
+pub mod tabs_in_doc_comments;
 pub mod temporary_assignment;
 pub mod to_digit_is_some;
 pub mod trait_bounds;
@@ -472,6 +474,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         &copies::IFS_SAME_COND,
         &copies::IF_SAME_THEN_ELSE,
         &copies::MATCH_SAME_ARMS,
+        &copies::SAME_FUNCTIONS_IN_IF_CONDITION,
         &copy_iterator::COPY_ITERATOR,
         &dbg_macro::DBG_MACRO,
         &default_trait_access::DEFAULT_TRAIT_ACCESS,
@@ -538,6 +541,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         &integer_division::INTEGER_DIVISION,
         &items_after_statements::ITEMS_AFTER_STATEMENTS,
         &large_enum_variant::LARGE_ENUM_VARIANT,
+        &large_stack_arrays::LARGE_STACK_ARRAYS,
         &len_zero::LEN_WITHOUT_IS_EMPTY,
         &len_zero::LEN_ZERO,
         &let_if_seq::USELESS_LET_IF_SEQ,
@@ -624,6 +628,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         &methods::USELESS_ASREF,
         &methods::WRONG_PUB_SELF_CONVENTION,
         &methods::WRONG_SELF_CONVENTION,
+        &methods::ZST_OFFSET,
         &minmax::MIN_MAX,
         &misc::CMP_NAN,
         &misc::CMP_OWNED,
@@ -716,6 +721,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         &suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL,
         &swap::ALMOST_SWAPPED,
         &swap::MANUAL_SWAP,
+        &tabs_in_doc_comments::TABS_IN_DOC_COMMENTS,
         &temporary_assignment::TEMPORARY_ASSIGNMENT,
         &to_digit_is_some::TO_DIGIT_IS_SOME,
         &trait_bounds::TYPE_REPETITION_IN_BOUNDS,
@@ -946,10 +952,13 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
     store.register_early_pass(|| box utils::internal_lints::ClippyLintsInternal);
     let enum_variant_name_threshold = conf.enum_variant_name_threshold;
     store.register_early_pass(move || box enum_variants::EnumVariantNames::new(enum_variant_name_threshold));
+    store.register_early_pass(|| box tabs_in_doc_comments::TabsInDocComments);
     store.register_late_pass(|| box unused_self::UnusedSelf);
     store.register_late_pass(|| box mutable_debug_assertion::DebugAssertWithMutCall);
     store.register_late_pass(|| box exit::Exit);
     store.register_late_pass(|| box to_digit_is_some::ToDigitIsSome);
+    let array_size_threshold = conf.array_size_threshold;
+    store.register_late_pass(move || box large_stack_arrays::LargeStackArrays::new(array_size_threshold));
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
@@ -989,6 +998,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&attrs::INLINE_ALWAYS),
         LintId::of(&checked_conversions::CHECKED_CONVERSIONS),
         LintId::of(&copies::MATCH_SAME_ARMS),
+        LintId::of(&copies::SAME_FUNCTIONS_IN_IF_CONDITION),
         LintId::of(&copy_iterator::COPY_ITERATOR),
         LintId::of(&default_trait_access::DEFAULT_TRAIT_ACCESS),
         LintId::of(&derive::EXPL_IMPL_CLONE_ON_COPY),
@@ -1003,6 +1013,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&if_not_else::IF_NOT_ELSE),
         LintId::of(&infinite_iter::MAYBE_INFINITE_ITER),
         LintId::of(&items_after_statements::ITEMS_AFTER_STATEMENTS),
+        LintId::of(&large_stack_arrays::LARGE_STACK_ARRAYS),
         LintId::of(&literal_representation::LARGE_DIGIT_GROUPS),
         LintId::of(&loops::EXPLICIT_INTO_ITER_LOOP),
         LintId::of(&loops::EXPLICIT_ITER_LOOP),
@@ -1176,6 +1187,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&methods::UNNECESSARY_FOLD),
         LintId::of(&methods::USELESS_ASREF),
         LintId::of(&methods::WRONG_SELF_CONVENTION),
+        LintId::of(&methods::ZST_OFFSET),
         LintId::of(&minmax::MIN_MAX),
         LintId::of(&misc::CMP_NAN),
         LintId::of(&misc::CMP_OWNED),
@@ -1243,6 +1255,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),
         LintId::of(&swap::ALMOST_SWAPPED),
         LintId::of(&swap::MANUAL_SWAP),
+        LintId::of(&tabs_in_doc_comments::TABS_IN_DOC_COMMENTS),
         LintId::of(&temporary_assignment::TEMPORARY_ASSIGNMENT),
         LintId::of(&to_digit_is_some::TO_DIGIT_IS_SOME),
         LintId::of(&transmute::CROSSPOINTER_TRANSMUTE),
@@ -1370,6 +1383,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&returns::NEEDLESS_RETURN),
         LintId::of(&returns::UNUSED_UNIT),
         LintId::of(&strings::STRING_LIT_AS_BYTES),
+        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),
         LintId::of(&types::FN_TO_NUMERIC_CAST),
@@ -1497,6 +1511,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         LintId::of(&methods::CLONE_DOUBLE_REF),
         LintId::of(&methods::TEMPORARY_CSTRING_AS_PTR),
         LintId::of(&methods::UNINIT_ASSUMED_INIT),
+        LintId::of(&methods::ZST_OFFSET),
         LintId::of(&minmax::MIN_MAX),
         LintId::of(&misc::CMP_NAN),
         LintId::of(&misc::FLOAT_CMP),

clippy_lints/src/methods/mod.rs

@@ -1065,6 +1065,23 @@ declare_clippy_lint! {
     "`.chcked_add/sub(x).unwrap_or(MAX/MIN)`"
 }
 
+declare_clippy_lint! {
+    /// **What it does:** Checks for `offset(_)`, `wrapping_`{`add`, `sub`}, etc. on raw pointers to
+    /// zero-sized types
+    ///
+    /// **Why is this bad?** This is a no-op, and likely unintended
+    ///
+    /// **Known problems:** None
+    ///
+    /// **Example:**
+    /// ```ignore
+    /// unsafe { (&() as *const ()).offest(1) };
+    /// ```
+    pub ZST_OFFSET,
+    correctness,
+    "Check for offset calculations on raw pointers to zero-sized types"
+}
+
 declare_lint_pass!(Methods => [
     OPTION_UNWRAP_USED,
     RESULT_UNWRAP_USED,
@@ -1109,6 +1126,7 @@ declare_lint_pass!(Methods => [
     SUSPICIOUS_MAP,
     UNINIT_ASSUMED_INIT,
     MANUAL_SATURATING_ARITHMETIC,
+    ZST_OFFSET,
 ]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {
@@ -1167,6 +1185,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {
             | ["unwrap_or", arith @ "checked_mul"] => {
                 manual_saturating_arithmetic::lint(cx, expr, &arg_lists, &arith["checked_".len()..])
             },
+            ["add"] | ["offset"] | ["sub"] | ["wrapping_offset"] | ["wrapping_add"] | ["wrapping_sub"] => {
+                check_pointer_offset(cx, expr, arg_lists[0])
+            },
             _ => {},
         }
 
@@ -3063,3 +3084,15 @@ fn contains_return(expr: &hir::Expr) -> bool {
     visitor.visit_expr(expr);
     visitor.found
 }
+
+fn check_pointer_offset(cx: &LateContext<'_, '_>, expr: &hir::Expr, args: &[hir::Expr]) {
+    if_chain! {
+        if args.len() == 2;
+        if let ty::RawPtr(ty::TypeAndMut { ref ty, .. }) = cx.tables.expr_ty(&args[0]).kind;
+        if let Ok(layout) = cx.tcx.layout_of(cx.param_env.and(ty));
+        if layout.is_zst();
+        then {
+            span_lint(cx, ZST_OFFSET, expr.span, "offset calculation on zero-sized value");
+        }
+    }
+}

clippy_lints/src/tabs_in_doc_comments.rs

@@ -0,0 +1,219 @@
+use crate::utils::span_lint_and_sugg;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
+use std::convert::TryFrom;
+use syntax::ast;
+use syntax::source_map::{BytePos, Span};
+
+declare_clippy_lint! {
+    /// **What it does:** Checks doc comments for usage of tab characters.
+    ///
+    /// **Why is this bad?** The rust style-guide promotes spaces instead of tabs for indentation.
+    /// To keep a consistent view on the source, also doc comments should not have tabs.
+    /// Also, explaining ascii-diagrams containing tabs can get displayed incorrectly when the
+    /// display settings of the author and reader differ.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// ///
+    /// /// Struct to hold two strings:
+    /// /// 	- first		one
+    /// /// 	- second	one
+    /// pub struct DoubleString {
+    ///    ///
+    ///    /// 	- First String:
+    ///    /// 		- needs to be inside here
+    ///    first_string: String,
+    ///    ///
+    ///    /// 	- Second String:
+    ///    /// 		- needs to be inside here
+    ///    second_string: String,
+    ///}
+    /// ```
+    ///
+    /// Will be converted to:
+     /// ```rust
+    /// ///
+    /// /// Struct to hold two strings:
+    /// ///     - first        one
+    /// ///     - second    one
+    /// pub struct DoubleString {
+    ///    ///
+    ///    ///     - First String:
+    ///    ///         - needs to be inside here
+    ///    first_string: String,
+    ///    ///
+    ///    ///     - Second String:
+    ///    ///         - needs to be inside here
+    ///    second_string: String,
+    ///}
+    /// ```
+    pub TABS_IN_DOC_COMMENTS,
+    style,
+    "using tabs in doc comments is not recommended"
+}
+
+declare_lint_pass!(TabsInDocComments => [TABS_IN_DOC_COMMENTS]);
+
+impl TabsInDocComments {
+    fn warn_if_tabs_in_doc(cx: &EarlyContext<'_>, attr: &ast::Attribute) {
+        if let ast::AttrKind::DocComment(comment) = attr.kind {
+            let comment = comment.as_str();
+
+            for (lo, hi) in get_chunks_of_tabs(&comment) {
+                let new_span = Span::new(
+                    attr.span.lo() + BytePos(lo),
+                    attr.span.lo() + BytePos(hi),
+                    attr.span.ctxt(),
+                );
+                span_lint_and_sugg(
+                    cx,
+                    TABS_IN_DOC_COMMENTS,
+                    new_span,
+                    "using tabs in doc comments is not recommended",
+                    "consider using four spaces per tab",
+                    "    ".repeat((hi - lo) as usize),
+                    Applicability::MaybeIncorrect,
+                );
+            }
+        }
+    }
+}
+
+impl EarlyLintPass for TabsInDocComments {
+    fn check_attribute(&mut self, cx: &EarlyContext<'_>, attribute: &ast::Attribute) {
+        Self::warn_if_tabs_in_doc(cx, &attribute);
+    }
+}
+
+///
+/// scans the string for groups of tabs and returns the start(inclusive) and end positions
+/// (exclusive) of all groups
+/// e.g. "sd\tasd\t\taa" will be converted to [(2, 3), (6, 8)] as
+///       012 3456 7 89
+///         ^-^  ^---^
+fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> {
+    let line_length_way_to_long = "doc comment longer than 2^32 chars";
+    let mut spans: Vec<(u32, u32)> = vec![];
+    let mut current_start: u32 = 0;
+
+    // tracker to decide if the last group of tabs is not closed by a non-tab character
+    let mut is_active = false;
+
+    let chars_array: Vec<_> = the_str.chars().collect();
+
+    if chars_array == vec!['\t'] {
+        return vec![(0, 1)];
+    }
+
+    for (index, arr) in chars_array.windows(2).enumerate() {
+        let index = u32::try_from(index).expect(line_length_way_to_long);
+        match arr {
+            ['\t', '\t'] => {
+                // either string starts with double tab, then we have to set it active,
+                // otherwise is_active is true anyway
+                is_active = true;
+            },
+            [_, '\t'] => {
+                // as ['\t', '\t'] is excluded, this has to be a start of a tab group,
+                // set indices accordingly
+                is_active = true;
+                current_start = index + 1;
+            },
+            ['\t', _] => {
+                // this now has to be an end of the group, hence we have to push a new tuple
+                is_active = false;
+                spans.push((current_start, index + 1));
+            },
+            _ => {},
+        }
+    }
+
+    // only possible when tabs are at the end, insert last group
+    if is_active {
+        spans.push((
+            current_start,
+            u32::try_from(the_str.chars().count()).expect(line_length_way_to_long),
+        ));
+    }
+
+    spans
+}
+
+#[cfg(test)]
+mod tests_for_get_chunks_of_tabs {
+    use super::get_chunks_of_tabs;
+
+    #[test]
+    fn test_empty_string() {
+        let res = get_chunks_of_tabs("");
+
+        assert_eq!(res, vec![]);
+    }
+
+    #[test]
+    fn test_simple() {
+        let res = get_chunks_of_tabs("sd\t\t\taa");
+
+        assert_eq!(res, vec![(2, 5)]);
+    }
+
+    #[test]
+    fn test_only_t() {
+        let res = get_chunks_of_tabs("\t\t");
+
+        assert_eq!(res, vec![(0, 2)]);
+    }
+
+    #[test]
+    fn test_only_one_t() {
+        let res = get_chunks_of_tabs("\t");
+
+        assert_eq!(res, vec![(0, 1)]);
+    }
+
+    #[test]
+    fn test_double() {
+        let res = get_chunks_of_tabs("sd\tasd\t\taa");
+
+        assert_eq!(res, vec![(2, 3), (6, 8)]);
+    }
+
+    #[test]
+    fn test_start() {
+        let res = get_chunks_of_tabs("\t\taa");
+
+        assert_eq!(res, vec![(0, 2)]);
+    }
+
+    #[test]
+    fn test_end() {
+        let res = get_chunks_of_tabs("aa\t\t");
+
+        assert_eq!(res, vec![(2, 4)]);
+    }
+
+    #[test]
+    fn test_start_single() {
+        let res = get_chunks_of_tabs("\taa");
+
+        assert_eq!(res, vec![(0, 1)]);
+    }
+
+    #[test]
+    fn test_end_single() {
+        let res = get_chunks_of_tabs("aa\t");
+
+        assert_eq!(res, vec![(2, 3)]);
+    }
+
+    #[test]
+    fn test_no_tabs() {
+        let res = get_chunks_of_tabs("dsfs");
+
+        assert_eq!(res, vec![]);
+    }
+}

clippy_lints/src/utils/conf.rs

@@ -151,6 +151,8 @@ define_Conf! {
     (trivial_copy_size_limit, "trivial_copy_size_limit", None => Option<u64>),
     /// Lint: TOO_MANY_LINES. The maximum number of lines a function or method can have
     (too_many_lines_threshold, "too_many_lines_threshold", 100 => u64),
+    /// Lint: LARGE_STACK_ARRAYS. The maximum allowed size for arrays on the stack
+    (array_size_threshold, "array_size_threshold", 512_000 => u64),
 }
 
 impl Default for Conf {

src/lintlist/mod.rs

@@ -6,7 +6,7 @@ pub use lint::Lint;
 pub use lint::LINT_LEVELS;
 
 // begin lint list, do not remove this comment, it’s used in `update_lints`
-pub const ALL_LINTS: [Lint; 333] = [
+pub const ALL_LINTS: [Lint; 337] = [
     Lint {
         name: "absurd_extreme_comparisons",
         group: "correctness",
@@ -903,6 +903,13 @@ pub const ALL_LINTS: [Lint; 333] = [
         deprecation: None,
         module: "large_enum_variant",
     },
+    Lint {
+        name: "large_stack_arrays",
+        group: "pedantic",
+        desc: "allocating large arrays on stack may cause stack overflow",
+        deprecation: None,
+        module: "large_stack_arrays",
+    },
     Lint {
         name: "len_without_is_empty",
         group: "style",
@@ -1708,6 +1715,13 @@ pub const ALL_LINTS: [Lint; 333] = [
         deprecation: None,
         module: "loops",
     },
+    Lint {
+        name: "same_functions_in_if_condition",
+        group: "pedantic",
+        desc: "consecutive `ifs` with the same function call",
+        deprecation: None,
+        module: "copies",
+    },
     Lint {
         name: "search_is_some",
         group: "complexity",
@@ -1862,6 +1876,13 @@ pub const ALL_LINTS: [Lint; 333] = [
         deprecation: None,
         module: "formatting",
     },
+    Lint {
+        name: "tabs_in_doc_comments",
+        group: "style",
+        desc: "using tabs in doc comments is not recommended",
+        deprecation: None,
+        module: "tabs_in_doc_comments",
+    },
     Lint {
         name: "temporary_assignment",
         group: "complexity",
@@ -2338,5 +2359,12 @@ pub const ALL_LINTS: [Lint; 333] = [
         deprecation: None,
         module: "unicode",
     },
+    Lint {
+        name: "zst_offset",
+        group: "correctness",
+        desc: "Check for offset calculations on raw pointers to zero-sized types",
+        deprecation: None,
+        module: "methods",
+    },
 ];
 // end lint list, do not remove this comment, it’s used in `update_lints`

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -1,4 +1,4 @@
-error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown field `foobar`, expected one of `blacklisted-names`, `cognitive-complexity-threshold`, `cyclomatic-complexity-threshold`, `doc-valid-idents`, `too-many-arguments-threshold`, `type-complexity-threshold`, `single-char-binding-names-threshold`, `too-large-for-stack`, `enum-variant-name-threshold`, `enum-variant-size-threshold`, `verbose-bit-mask-threshold`, `literal-representation-threshold`, `trivial-copy-size-limit`, `too-many-lines-threshold`, `third-party` at line 5 column 1
+error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown field `foobar`, expected one of `blacklisted-names`, `cognitive-complexity-threshold`, `cyclomatic-complexity-threshold`, `doc-valid-idents`, `too-many-arguments-threshold`, `type-complexity-threshold`, `single-char-binding-names-threshold`, `too-large-for-stack`, `enum-variant-name-threshold`, `enum-variant-size-threshold`, `verbose-bit-mask-threshold`, `literal-representation-threshold`, `trivial-copy-size-limit`, `too-many-lines-threshold`, `array-size-threshold`, `third-party` at line 5 column 1
 
 error: aborting due to previous error
 

tests/ui/large_stack_arrays.rs

@@ -0,0 +1,30 @@
+#![warn(clippy::large_stack_arrays)]
+#![allow(clippy::large_enum_variant)]
+
+#[derive(Clone, Copy)]
+struct S {
+    pub data: [u64; 32],
+}
+
+#[derive(Clone, Copy)]
+enum E {
+    S(S),
+    T(u32),
+}
+
+fn main() {
+    let bad = (
+        [0u32; 20_000_000],
+        [S { data: [0; 32] }; 5000],
+        [Some(""); 20_000_000],
+        [E::T(0); 5000],
+    );
+
+    let good = (
+        [0u32; 1000],
+        [S { data: [0; 32] }; 1000],
+        [Some(""); 1000],
+        [E::T(0); 1000],
+        [(); 20_000_000],
+    );
+}

tests/ui/large_stack_arrays.stderr

@@ -0,0 +1,35 @@
+error: allocating a local array larger than 512000 bytes
+  --> $DIR/large_stack_arrays.rs:17:9
+   |
+LL |         [0u32; 20_000_000],
+   |         ^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::large-stack-arrays` implied by `-D warnings`
+   = help: consider allocating on the heap with vec![0u32; 20_000_000].into_boxed_slice()
+
+error: allocating a local array larger than 512000 bytes
+  --> $DIR/large_stack_arrays.rs:18:9
+   |
+LL |         [S { data: [0; 32] }; 5000],
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider allocating on the heap with vec![S { data: [0; 32] }; 5000].into_boxed_slice()
+
+error: allocating a local array larger than 512000 bytes
+  --> $DIR/large_stack_arrays.rs:19:9
+   |
+LL |         [Some(""); 20_000_000],
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider allocating on the heap with vec![Some(""); 20_000_000].into_boxed_slice()
+
+error: allocating a local array larger than 512000 bytes
+  --> $DIR/large_stack_arrays.rs:20:9
+   |
+LL |         [E::T(0); 5000],
+   |         ^^^^^^^^^^^^^^^
+   |
+   = help: consider allocating on the heap with vec![E::T(0); 5000].into_boxed_slice()
+
+error: aborting due to 4 previous errors
+

tests/ui/same_functions_in_if_condition.rs

@@ -0,0 +1,80 @@
+#![warn(clippy::same_functions_in_if_condition)]
+#![allow(clippy::ifs_same_cond)] // This warning is different from `ifs_same_cond`.
+#![allow(clippy::if_same_then_else, clippy::comparison_chain)] // all empty blocks
+
+fn function() -> bool {
+    true
+}
+
+fn fn_arg(_arg: u8) -> bool {
+    true
+}
+
+struct Struct;
+
+impl Struct {
+    fn method(&self) -> bool {
+        true
+    }
+    fn method_arg(&self, _arg: u8) -> bool {
+        true
+    }
+}
+
+fn ifs_same_cond_fn() {
+    let a = 0;
+    let obj = Struct;
+
+    if function() {
+    } else if function() {
+        //~ ERROR ifs same condition
+    }
+
+    if fn_arg(a) {
+    } else if fn_arg(a) {
+        //~ ERROR ifs same condition
+    }
+
+    if obj.method() {
+    } else if obj.method() {
+        //~ ERROR ifs same condition
+    }
+
+    if obj.method_arg(a) {
+    } else if obj.method_arg(a) {
+        //~ ERROR ifs same condition
+    }
+
+    let mut v = vec![1];
+    if v.pop() == None {
+        //~ ERROR ifs same condition
+    } else if v.pop() == None {
+    }
+
+    if v.len() == 42 {
+        //~ ERROR ifs same condition
+    } else if v.len() == 42 {
+    }
+
+    if v.len() == 1 {
+        // ok, different conditions
+    } else if v.len() == 2 {
+    }
+
+    if fn_arg(0) {
+        // ok, different arguments.
+    } else if fn_arg(1) {
+    }
+
+    if obj.method_arg(0) {
+        // ok, different arguments.
+    } else if obj.method_arg(1) {
+    }
+
+    if a == 1 {
+        // ok, warning is on `ifs_same_cond` behalf.
+    } else if a == 1 {
+    }
+}
+
+fn main() {}

tests/ui/same_functions_in_if_condition.stderr

@@ -0,0 +1,75 @@
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:29:15
+   |
+LL |     } else if function() {
+   |               ^^^^^^^^^^
+   |
+   = note: `-D clippy::same-functions-in-if-condition` implied by `-D warnings`
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:28:8
+   |
+LL |     if function() {
+   |        ^^^^^^^^^^
+
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:34:15
+   |
+LL |     } else if fn_arg(a) {
+   |               ^^^^^^^^^
+   |
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:33:8
+   |
+LL |     if fn_arg(a) {
+   |        ^^^^^^^^^
+
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:39:15
+   |
+LL |     } else if obj.method() {
+   |               ^^^^^^^^^^^^
+   |
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:38:8
+   |
+LL |     if obj.method() {
+   |        ^^^^^^^^^^^^
+
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:44:15
+   |
+LL |     } else if obj.method_arg(a) {
+   |               ^^^^^^^^^^^^^^^^^
+   |
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:43:8
+   |
+LL |     if obj.method_arg(a) {
+   |        ^^^^^^^^^^^^^^^^^
+
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:51:15
+   |
+LL |     } else if v.pop() == None {
+   |               ^^^^^^^^^^^^^^^
+   |
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:49:8
+   |
+LL |     if v.pop() == None {
+   |        ^^^^^^^^^^^^^^^
+
+error: this `if` has the same function call as a previous if
+  --> $DIR/same_functions_in_if_condition.rs:56:15
+   |
+LL |     } else if v.len() == 42 {
+   |               ^^^^^^^^^^^^^
+   |
+note: same as this
+  --> $DIR/same_functions_in_if_condition.rs:54:8
+   |
+LL |     if v.len() == 42 {
+   |        ^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+

tests/ui/tabs_in_doc_comments.fixed

@@ -0,0 +1,22 @@
+// run-rustfix
+
+#![warn(clippy::tabs_in_doc_comments)]
+#[allow(dead_code)]
+
+///
+/// Struct to hold two strings:
+///     - first        one
+///     - second    one
+pub struct DoubleString {
+    ///
+    ///     - First String:
+    ///         - needs to be inside here
+    first_string: String,
+    ///
+    ///     - Second String:
+    ///         - needs to be inside here
+    second_string: String,
+}
+
+/// This is main
+fn main() {}

tests/ui/tabs_in_doc_comments.rs

@@ -0,0 +1,22 @@
+// run-rustfix
+
+#![warn(clippy::tabs_in_doc_comments)]
+#[allow(dead_code)]
+
+///
+/// Struct to hold two strings:
+/// 	- first		one
+/// 	- second	one
+pub struct DoubleString {
+    ///
+    /// 	- First String:
+    /// 		- needs to be inside here
+    first_string: String,
+    ///
+    /// 	- Second String:
+    /// 		- needs to be inside here
+    second_string: String,
+}
+
+/// This is main
+fn main() {}

tests/ui/tabs_in_doc_comments.stderr

@@ -0,0 +1,52 @@
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:12:9
+   |
+LL |     ///     - First String:
+   |         ^^^^ help: consider using four spaces per tab
+   |
+   = note: `-D clippy::tabs-in-doc-comments` implied by `-D warnings`
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:13:9
+   |
+LL |     ///         - needs to be inside here
+   |         ^^^^^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:16:9
+   |
+LL |     ///     - Second String:
+   |         ^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:17:9
+   |
+LL |     ///         - needs to be inside here
+   |         ^^^^^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:8:5
+   |
+LL | ///     - first        one
+   |     ^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:8:13
+   |
+LL | ///     - first        one
+   |                ^^^^^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:9:5
+   |
+LL | ///     - second    one
+   |     ^^^^ help: consider using four spaces per tab
+
+error: using tabs in doc comments is not recommended
+  --> $DIR/tabs_in_doc_comments.rs:9:14
+   |
+LL | ///     - second    one
+   |                 ^^^^ help: consider using four spaces per tab
+
+error: aborting due to 8 previous errors
+

tests/ui/zero_offset.rs

@@ -0,0 +1,12 @@
+fn main() {
+    unsafe {
+        let x = &() as *const ();
+        x.offset(0);
+        x.wrapping_add(0);
+        x.sub(0);
+        x.wrapping_sub(0);
+
+        let y = &1 as *const u8;
+        y.offset(0);
+    }
+}

tests/ui/zero_offset.stderr

@@ -0,0 +1,9 @@
+error[E0606]: casting `&i32` as `*const u8` is invalid
+  --> $DIR/zero_offset.rs:9:17
+   |
+LL |         let y = &1 as *const u8;
+   |                 ^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0606`.