Deny missing_docs_in_private_items in some modules

clippy_lints/src/utils/comparisons.rs

@@ -1,14 +1,23 @@
+//! Utility functions about comparison operators.
+
+#![deny(missing_docs_in_private_items)]
+
 use rustc::hir::{BinOp_, Expr};
 
 #[derive(PartialEq, Eq, Debug, Copy, Clone)]
+/// Represent a normalized comparison operator.
 pub enum Rel {
+    /// `<`
     Lt,
+    /// `<=`
     Le,
+    /// `==`
     Eq,
+    /// `!=`
     Ne,
 }
 
-/// Put the expression in the form  `lhs < rhs` or `lhs <= rhs`.
+/// Put the expression in the form  `lhs < rhs`, `lhs <= rhs`, `lhs == rhs` or `lhs != rhs`.
 pub fn normalize_comparison<'a>(op: BinOp_, lhs: &'a Expr, rhs: &'a Expr)
                                 -> Option<(Rel, &'a Expr, &'a Expr)> {
     match op {

clippy_lints/src/utils/conf.rs

@@ -1,3 +1,7 @@
+//! Read configurations files.
+
+#![deny(missing_docs_in_private_items)]
+
 use std::{fmt, fs, io};
 use std::io::Read;
 use syntax::{ast, codemap, ptr};
@@ -32,9 +36,20 @@ pub fn file(args: &[ptr::P<ast::MetaItem>]) -> Result<Option<token::InternedStri
 /// Error from reading a configuration file.
 #[derive(Debug)]
 pub enum Error {
+    /// An I/O error.
     Io(io::Error),
+    /// The file is not valid TOML.
     Toml(Vec<toml::ParserError>),
-    Type(&'static str, &'static str, &'static str),
+    /// Type error.
+    Type(
+        /// The name of the key.
+        &'static str,
+        /// The expected type.
+        &'static str,
+        /// The type we got instead.
+        &'static str
+    ),
+    /// There is an unknown key is the file.
     UnknownKey(String),
 }
 

clippy_lints/src/utils/higher.rs

@@ -1,5 +1,7 @@
 //! This module contains functions for retrieve the original AST from lowered `hir`.
 
+#![deny(missing_docs_in_private_items)]
+
 use rustc::hir;
 use rustc::lint::LateContext;
 use syntax::ast;
@@ -33,14 +35,17 @@ pub fn binop(op: hir::BinOp_) -> ast::BinOpKind {
 /// Represent a range akin to `ast::ExprKind::Range`.
 #[derive(Debug, Copy, Clone)]
 pub struct Range<'a> {
+    /// The lower bound of the range, or `None` for ranges such as `..X`.
     pub start: Option<&'a hir::Expr>,
+    /// The upper bound of the range, or `None` for ranges such as `X..`.
     pub end: Option<&'a hir::Expr>,
+    /// Whether the interval is open or closed.
     pub limits: ast::RangeLimits,
 }
 
 /// Higher a `hir` range to something similar to `ast::ExprKind::Range`.
 pub fn range(expr: &hir::Expr) -> Option<Range> {
-    // To be removed when ranges get stable.
+    /// Skip unstable blocks. To be removed when ranges get stable.
     fn unwrap_unstable(expr: &hir::Expr) -> &hir::Expr {
         if let hir::ExprBlock(ref block) = expr.node {
             if block.rules == hir::BlockCheckMode::PushUnstableBlock || block.rules == hir::BlockCheckMode::PopUnstableBlock {
@@ -53,6 +58,7 @@ pub fn range(expr: &hir::Expr) -> Option<Range> {
         expr
     }
 
+    /// Find the field named `name` in the field. Always return `Some` for convenience.
     fn get_field<'a>(name: &str, fields: &'a [hir::Field]) -> Option<&'a hir::Expr> {
         let expr = &fields.iter()
                           .find(|field| field.name.node.as_str() == name)

clippy_lints/src/utils/sugg.rs

@@ -1,3 +1,6 @@
+//! Contains utility functions to generate suggestions.
+#![deny(missing_docs_in_private_items)]
+
 use rustc::hir;
 use rustc::lint::{EarlyContext, LateContext, LintContext};
 use rustc_errors;
@@ -35,6 +38,7 @@ impl<'a> Display for Sugg<'a> {
 
 #[allow(wrong_self_convention)] // ok, because of the function `as_ty` method
 impl<'a> Sugg<'a> {
+    /// Prepare a suggestion from an expression.
     pub fn hir_opt(cx: &LateContext, expr: &hir::Expr) -> Option<Sugg<'a>> {
         snippet_opt(cx, expr.span).map(|snippet| {
             let snippet = Cow::Owned(snippet);
@@ -72,10 +76,12 @@ impl<'a> Sugg<'a> {
         })
     }
 
+    /// Convenience function around `hir_opt` for suggestions with a default text.
     pub fn hir(cx: &LateContext, expr: &hir::Expr, default: &'a str) -> Sugg<'a> {
         Self::hir_opt(cx, expr).unwrap_or_else(|| Sugg::NonParen(Cow::Borrowed(default)))
     }
 
+    /// Prepare a suggestion from an expression.
     pub fn ast(cx: &EarlyContext, expr: &ast::Expr, default: &'a str) -> Sugg<'a> {
         use syntax::ast::RangeLimits;
 
@@ -193,12 +199,16 @@ impl<'a> std::ops::Not for Sugg<'a> {
     }
 }
 
+/// Helper type to display either `foo` or `(foo)`.
 struct ParenHelper<T> {
+    /// Wether parenthesis are needed.
     paren: bool,
+    /// The main thing to display.
     wrapped: T,
 }
 
 impl<T> ParenHelper<T> {
+    /// Build a `ParenHelper`.
     fn new(paren: bool, wrapped: T) -> Self {
         ParenHelper {
             paren: paren,
@@ -230,14 +240,18 @@ pub fn make_unop(op: &str, expr: Sugg) -> Sugg<'static> {
 /// Precedence of shift operator relative to other arithmetic operation is often confusing so
 /// parenthesis will always be added for a mix of these.
 pub fn make_assoc(op: AssocOp, lhs: &Sugg, rhs: &Sugg) -> Sugg<'static> {
+    /// Wether the operator is a shift operator `<<` or `>>`.
     fn is_shift(op: &AssocOp) -> bool {
         matches!(*op, AssocOp::ShiftLeft | AssocOp::ShiftRight)
     }
 
+    /// Wether the operator is a arithmetic operator (`+`, `-`, `*`, `/`, `%`).
     fn is_arith(op: &AssocOp) -> bool {
         matches!(*op, AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide | AssocOp::Modulus)
     }
 
+    /// Wether the operator `op` needs parenthesis with the operator `other` in the direction
+    /// `dir`.
     fn needs_paren(op: &AssocOp, other: &AssocOp, dir: Associativity) -> bool {
         other.precedence() < op.precedence() ||
             (other.precedence() == op.precedence() &&
@@ -298,10 +312,15 @@ pub fn make_binop(op: ast::BinOpKind, lhs: &Sugg, rhs: &Sugg) -> Sugg<'static> {
 }
 
 #[derive(PartialEq, Eq)]
+/// Operator associativity.
 enum Associativity {
+    /// The operator is both left-associative and right-associative.
     Both,
+    /// The operator is left-associative.
     Left,
+    /// The operator is not associative.
     None,
+    /// The operator is right-associative.
     Right,
 }
 
@@ -383,6 +402,7 @@ fn indentation<T: LintContext>(cx: &T, span: Span) -> Option<String> {
     }
 }
 
+/// Convenience extension trait for `DiagnosticBuilder`.
 pub trait DiagnosticBuilderExt<T: LintContext> {
     /// Suggests to add an attribute to an item.
     ///