src/tools/clippy/clippy_lints/src/formatting.rs - toolchain/rustc - Git at Google

 use crate::utils::{differing_macro_contexts, snippet_opt, span_help_and_lint, span_note_and_lint};
 use if_chain::if_chain;
 use rustc::lint::{in_external_macro, EarlyContext, EarlyLintPass, LintArray, LintPass};
 use rustc::{declare_lint_pass, declare_tool_lint};
 use syntax::ast::*;

 declare_clippy_lint! {
     /// **What it does:** Checks for use of the non-existent `=*`, `=!` and `=-`
     /// operators.
     ///
     /// **Why is this bad?** This is either a typo of `*=`, `!=` or `-=` or
     /// confusing.
     ///
     /// **Known problems:** None.
     ///
     /// **Example:**
     /// ```rust,ignore
     /// a =- 42; // confusing, should it be `a -= 42` or `a = -42`?
     /// ```
     pub SUSPICIOUS_ASSIGNMENT_FORMATTING,
     style,
     "suspicious formatting of `*=`, `-=` or `!=`"
 }

 declare_clippy_lint! {
     /// **What it does:** Checks the formatting of a unary operator on the right hand side
     /// of a binary operator. It lints if there is no space between the binary and unary operators,
     /// but there is a space between the unary and its operand.
     ///
     /// **Why is this bad?** This is either a typo in the binary operator or confusing.
     ///
     /// **Known problems:** None.
     ///
     /// **Example:**
     /// ```rust,ignore
     /// if foo <- 30 { // this should be `foo < -30` but looks like a different operator
     /// }
     ///
     /// if foo &&! bar { // this should be `foo && !bar` but looks like a different operator
     /// }
     /// ```
     pub SUSPICIOUS_UNARY_OP_FORMATTING,
     style,
     "suspicious formatting of unary `-` or `!` on the RHS of a BinOp"
 }

 declare_clippy_lint! {
     /// **What it does:** Checks for formatting of `else`. It lints if the `else`
     /// is followed immediately by a newline or the `else` seems to be missing.
     ///
     /// **Why is this bad?** This is probably some refactoring remnant, even if the
     /// code is correct, it might look confusing.
     ///
     /// **Known problems:** None.
     ///
     /// **Example:**
     /// ```rust,ignore
     /// if foo {
     /// } { // looks like an `else` is missing here
     /// }
     ///
     /// if foo {
     /// } if bar { // looks like an `else` is missing here
     /// }
     ///
     /// if foo {
     /// } else
     ///
     /// { // this is the `else` block of the previous `if`, but should it be?
     /// }
     ///
     /// if foo {
     /// } else
     ///
     /// if bar { // this is the `else` block of the previous `if`, but should it be?
     /// }
     /// ```
     pub SUSPICIOUS_ELSE_FORMATTING,
     style,
     "suspicious formatting of `else`"
 }

 declare_clippy_lint! {
     /// **What it does:** Checks for possible missing comma in an array. It lints if
     /// an array element is a binary operator expression and it lies on two lines.
     ///
     /// **Why is this bad?** This could lead to unexpected results.
     ///
     /// **Known problems:** None.
     ///
     /// **Example:**
     /// ```rust,ignore
     /// let a = &[
     ///     -1, -2, -3 // <= no comma here
     ///     -4, -5, -6
     /// ];
     /// ```
     pub POSSIBLE_MISSING_COMMA,
     correctness,
     "possible missing comma in array"
 }

 declare_lint_pass!(Formatting => [
     SUSPICIOUS_ASSIGNMENT_FORMATTING,
     SUSPICIOUS_UNARY_OP_FORMATTING,
     SUSPICIOUS_ELSE_FORMATTING,
     POSSIBLE_MISSING_COMMA
 ]);

 impl EarlyLintPass for Formatting {
     fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) {
         for w in block.stmts.windows(2) {
             match (&w[0].kind, &w[1].kind) {
                 (&StmtKind::Expr(ref first), &StmtKind::Expr(ref second))
                 | (&StmtKind::Expr(ref first), &StmtKind::Semi(ref second)) => {
                     check_missing_else(cx, first, second);
                 },
                 _ => (),
             }
         }
     }

     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         check_assign(cx, expr);
         check_unop(cx, expr);
         check_else(cx, expr);
         check_array(cx, expr);
     }
 }

 /// Implementation of the `SUSPICIOUS_ASSIGNMENT_FORMATTING` lint.
 fn check_assign(cx: &EarlyContext<'_>, expr: &Expr) {
     if let ExprKind::Assign(ref lhs, ref rhs) = expr.kind {
         if !differing_macro_contexts(lhs.span, rhs.span) && !lhs.span.from_expansion() {
             let eq_span = lhs.span.between(rhs.span);
             if let ExprKind::Unary(op, ref sub_rhs) = rhs.kind {
                 if let Some(eq_snippet) = snippet_opt(cx, eq_span) {
                     let op = UnOp::to_string(op);
                     let eqop_span = lhs.span.between(sub_rhs.span);
                     if eq_snippet.ends_with('=') {
                         span_note_and_lint(
                             cx,
                             SUSPICIOUS_ASSIGNMENT_FORMATTING,
                             eqop_span,
                             &format!(
                                 "this looks like you are trying to use `.. {op}= ..`, but you \
                                  really are doing `.. = ({op} ..)`",
                                 op = op
                             ),
                             eqop_span,
                             &format!("to remove this lint, use either `{op}=` or `= {op}`", op = op),
                         );
                     }
                 }
             }
         }
     }
 }

 /// Implementation of the `SUSPICIOUS_UNARY_OP_FORMATTING` lint.
 fn check_unop(cx: &EarlyContext<'_>, expr: &Expr) {
     if_chain! {
         if let ExprKind::Binary(ref binop, ref lhs, ref rhs) = expr.kind;
         if !differing_macro_contexts(lhs.span, rhs.span) && !lhs.span.from_expansion();
         // span between BinOp LHS and RHS
         let binop_span = lhs.span.between(rhs.span);
         // if RHS is a UnOp
         if let ExprKind::Unary(op, ref un_rhs) = rhs.kind;
         // from UnOp operator to UnOp operand
         let unop_operand_span = rhs.span.until(un_rhs.span);
         if let Some(binop_snippet) = snippet_opt(cx, binop_span);
         if let Some(unop_operand_snippet) = snippet_opt(cx, unop_operand_span);
         let binop_str = BinOpKind::to_string(&binop.node);
         // no space after BinOp operator and space after UnOp operator
         if binop_snippet.ends_with(binop_str) && unop_operand_snippet.ends_with(' ');
         then {
             let unop_str = UnOp::to_string(op);
             let eqop_span = lhs.span.between(un_rhs.span);
             span_help_and_lint(
                 cx,
                 SUSPICIOUS_UNARY_OP_FORMATTING,
                 eqop_span,
                 &format!(
                     "by not having a space between `{binop}` and `{unop}` it looks like \
                      `{binop}{unop}` is a single operator",
                     binop = binop_str,
                     unop = unop_str
                 ),
                 &format!(
                     "put a space between `{binop}` and `{unop}` and remove the space after `{unop}`",
                     binop = binop_str,
                     unop = unop_str
                 ),
             );
         }
     }
 }

 /// Implementation of the `SUSPICIOUS_ELSE_FORMATTING` lint for weird `else`.
 fn check_else(cx: &EarlyContext<'_>, expr: &Expr) {
     if_chain! {
         if let ExprKind::If(_, then, Some(else_)) = &expr.kind;
         if is_block(else_) || is_if(else_);
         if !differing_macro_contexts(then.span, else_.span);
         if !then.span.from_expansion() && !in_external_macro(cx.sess, expr.span);

         // workaround for rust-lang/rust#43081
         if expr.span.lo().0 != 0 && expr.span.hi().0 != 0;

         // this will be a span from the closing ‘}’ of the “then” block (excluding) to
         // the “if” of the “else if” block (excluding)
         let else_span = then.span.between(else_.span);

         // the snippet should look like " else \n    " with maybe comments anywhere
         // it’s bad when there is a ‘\n’ after the “else”
         if let Some(else_snippet) = snippet_opt(cx, else_span);
         if let Some(else_pos) = else_snippet.find("else");
         if else_snippet[else_pos..].contains('\n');
         let else_desc = if is_if(else_) { "if" } else { "{..}" };

         then {
             span_note_and_lint(
                 cx,
                 SUSPICIOUS_ELSE_FORMATTING,
                 else_span,
                 &format!("this is an `else {}` but the formatting might hide it", else_desc),
                 else_span,
                 &format!(
                     "to remove this lint, remove the `else` or remove the new line between \
                      `else` and `{}`",
                     else_desc,
                 ),
             );
         }
     }
 }

 #[must_use]
 fn has_unary_equivalent(bin_op: BinOpKind) -> bool {
     // &, *, -
     bin_op == BinOpKind::And || bin_op == BinOpKind::Mul || bin_op == BinOpKind::Sub
 }

 /// Implementation of the `POSSIBLE_MISSING_COMMA` lint for array
 fn check_array(cx: &EarlyContext<'_>, expr: &Expr) {
     if let ExprKind::Array(ref array) = expr.kind {
         for element in array {
             if let ExprKind::Binary(ref op, ref lhs, _) = element.kind {
                 if has_unary_equivalent(op.node) && !differing_macro_contexts(lhs.span, op.span) {
                     let space_span = lhs.span.between(op.span);
                     if let Some(space_snippet) = snippet_opt(cx, space_span) {
                         let lint_span = lhs.span.with_lo(lhs.span.hi());
                         if space_snippet.contains('\n') {
                             span_note_and_lint(
                                 cx,
                                 POSSIBLE_MISSING_COMMA,
                                 lint_span,
                                 "possibly missing a comma here",
                                 lint_span,
                                 "to remove this lint, add a comma or write the expr in a single line",
                             );
                         }
                     }
                 }
             }
         }
     }
 }

 fn check_missing_else(cx: &EarlyContext<'_>, first: &Expr, second: &Expr) {
     if !differing_macro_contexts(first.span, second.span)
         && !first.span.from_expansion()
         && is_if(first)
         && (is_block(second) || is_if(second))
     {
         // where the else would be
         let else_span = first.span.between(second.span);

         if let Some(else_snippet) = snippet_opt(cx, else_span) {
             if !else_snippet.contains('\n') {
                 let (looks_like, next_thing) = if is_if(second) {
                     ("an `else if`", "the second `if`")
                 } else {
                     ("an `else {..}`", "the next block")
                 };

                 span_note_and_lint(
                     cx,
                     SUSPICIOUS_ELSE_FORMATTING,
                     else_span,
                     &format!("this looks like {} but the `else` is missing", looks_like),
                     else_span,
                     &format!(
                         "to remove this lint, add the missing `else` or add a new line before {}",
                         next_thing,
                     ),
                 );
             }
         }
     }
 }

 fn is_block(expr: &Expr) -> bool {
     if let ExprKind::Block(..) = expr.kind {
         true
     } else {
         false
     }
 }

 /// Check if the expression is an `if` or `if let`
 fn is_if(expr: &Expr) -> bool {
     if let ExprKind::If(..) = expr.kind {
         true
     } else {
         false
     }
 }
	use crate::utils::{differing_macro_contexts, snippet_opt, span_help_and_lint, span_note_and_lint};
	use if_chain::if_chain;
	use rustc::lint::{in_external_macro, EarlyContext, EarlyLintPass, LintArray, LintPass};
	use rustc::{declare_lint_pass, declare_tool_lint};
	use syntax::ast::*;

	declare_clippy_lint! {
	/// What it does: Checks for use of the non-existent `=*`, `=!` and `=-`
	/// operators.
	///
	/// Why is this bad? This is either a typo of `*=`, `!=` or `-=` or
	/// confusing.
	///
	/// Known problems: None.
	///
	/// Example:
	/// ```rust,ignore
	/// a =- 42; // confusing, should it be `a -= 42` or `a = -42`?
	/// ```
	pub SUSPICIOUS_ASSIGNMENT_FORMATTING,
	style,
	"suspicious formatting of `*=`, `-=` or `!=`"
	}

	declare_clippy_lint! {
	/// What it does: Checks the formatting of a unary operator on the right hand side
	/// of a binary operator. It lints if there is no space between the binary and unary operators,
	/// but there is a space between the unary and its operand.
	///
	/// Why is this bad? This is either a typo in the binary operator or confusing.
	///
	/// Known problems: None.
	///
	/// Example:
	/// ```rust,ignore
	/// if foo <- 30 { // this should be `foo < -30` but looks like a different operator
	/// }
	///
	/// if foo &&! bar { // this should be `foo && !bar` but looks like a different operator
	/// }
	/// ```
	pub SUSPICIOUS_UNARY_OP_FORMATTING,
	style,
	"suspicious formatting of unary `-` or `!` on the RHS of a BinOp"
	}

	declare_clippy_lint! {
	/// What it does: Checks for formatting of `else`. It lints if the `else`
	/// is followed immediately by a newline or the `else` seems to be missing.
	///
	/// Why is this bad? This is probably some refactoring remnant, even if the
	/// code is correct, it might look confusing.
	///
	/// Known problems: None.
	///
	/// Example:
	/// ```rust,ignore
	/// if foo {
	/// } { // looks like an `else` is missing here
	/// }
	///
	/// if foo {
	/// } if bar { // looks like an `else` is missing here
	/// }
	///
	/// if foo {
	/// } else
	///
	/// { // this is the `else` block of the previous `if`, but should it be?
	/// }
	///
	/// if foo {
	/// } else
	///
	/// if bar { // this is the `else` block of the previous `if`, but should it be?
	/// }
	/// ```
	pub SUSPICIOUS_ELSE_FORMATTING,
	style,
	"suspicious formatting of `else`"
	}

	declare_clippy_lint! {
	/// What it does: Checks for possible missing comma in an array. It lints if
	/// an array element is a binary operator expression and it lies on two lines.
	///
	/// Why is this bad? This could lead to unexpected results.
	///
	/// Known problems: None.
	///
	/// Example:
	/// ```rust,ignore
	/// let a = &[
	/// -1, -2, -3 // <= no comma here
	/// -4, -5, -6
	/// ];
	/// ```
	pub POSSIBLE_MISSING_COMMA,
	correctness,
	"possible missing comma in array"
	}

	declare_lint_pass!(Formatting => [
	SUSPICIOUS_ASSIGNMENT_FORMATTING,
	SUSPICIOUS_UNARY_OP_FORMATTING,
	SUSPICIOUS_ELSE_FORMATTING,
	POSSIBLE_MISSING_COMMA
	]);

	impl EarlyLintPass for Formatting {
	fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) {
	for w in block.stmts.windows(2) {
	match (&w[0].kind, &w[1].kind) {
	(&StmtKind::Expr(ref first), &StmtKind::Expr(ref second))
	\| (&StmtKind::Expr(ref first), &StmtKind::Semi(ref second)) => {
	check_missing_else(cx, first, second);
	},
	_ => (),
	}
	}
	}

	fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
	check_assign(cx, expr);
	check_unop(cx, expr);
	check_else(cx, expr);
	check_array(cx, expr);
	}
	}

	/// Implementation of the `SUSPICIOUS_ASSIGNMENT_FORMATTING` lint.
	fn check_assign(cx: &EarlyContext<'_>, expr: &Expr) {
	if let ExprKind::Assign(ref lhs, ref rhs) = expr.kind {
	if !differing_macro_contexts(lhs.span, rhs.span) && !lhs.span.from_expansion() {
	let eq_span = lhs.span.between(rhs.span);
	if let ExprKind::Unary(op, ref sub_rhs) = rhs.kind {
	if let Some(eq_snippet) = snippet_opt(cx, eq_span) {
	let op = UnOp::to_string(op);
	let eqop_span = lhs.span.between(sub_rhs.span);
	if eq_snippet.ends_with('=') {
	span_note_and_lint(
	cx,
	SUSPICIOUS_ASSIGNMENT_FORMATTING,
	eqop_span,
	&format!(
	"this looks like you are trying to use `.. {op}= ..`, but you \
	really are doing `.. = ({op} ..)`",
	op = op
	),
	eqop_span,
	&format!("to remove this lint, use either `{op}=` or `= {op}`", op = op),
	);
	}
	}
	}
	}
	}
	}

	/// Implementation of the `SUSPICIOUS_UNARY_OP_FORMATTING` lint.
	fn check_unop(cx: &EarlyContext<'_>, expr: &Expr) {
	if_chain! {
	if let ExprKind::Binary(ref binop, ref lhs, ref rhs) = expr.kind;
	if !differing_macro_contexts(lhs.span, rhs.span) && !lhs.span.from_expansion();
	// span between BinOp LHS and RHS
	let binop_span = lhs.span.between(rhs.span);
	// if RHS is a UnOp
	if let ExprKind::Unary(op, ref un_rhs) = rhs.kind;
	// from UnOp operator to UnOp operand
	let unop_operand_span = rhs.span.until(un_rhs.span);
	if let Some(binop_snippet) = snippet_opt(cx, binop_span);
	if let Some(unop_operand_snippet) = snippet_opt(cx, unop_operand_span);
	let binop_str = BinOpKind::to_string(&binop.node);
	// no space after BinOp operator and space after UnOp operator
	if binop_snippet.ends_with(binop_str) && unop_operand_snippet.ends_with(' ');
	then {
	let unop_str = UnOp::to_string(op);
	let eqop_span = lhs.span.between(un_rhs.span);
	span_help_and_lint(
	cx,
	SUSPICIOUS_UNARY_OP_FORMATTING,
	eqop_span,
	&format!(
	"by not having a space between `{binop}` and `{unop}` it looks like \
	`{binop}{unop}` is a single operator",
	binop = binop_str,
	unop = unop_str
	),
	&format!(
	"put a space between `{binop}` and `{unop}` and remove the space after `{unop}`",
	binop = binop_str,
	unop = unop_str
	),
	);
	}
	}
	}

	/// Implementation of the `SUSPICIOUS_ELSE_FORMATTING` lint for weird `else`.
	fn check_else(cx: &EarlyContext<'_>, expr: &Expr) {
	if_chain! {
	if let ExprKind::If(_, then, Some(else_)) = &expr.kind;
	if is_block(else_) \|\| is_if(else_);
	if !differing_macro_contexts(then.span, else_.span);
	if !then.span.from_expansion() && !in_external_macro(cx.sess, expr.span);

	// workaround for rust-lang/rust#43081
	if expr.span.lo().0 != 0 && expr.span.hi().0 != 0;

	// this will be a span from the closing ‘}’ of the “then” block (excluding) to
	// the “if” of the “else if” block (excluding)
	let else_span = then.span.between(else_.span);

	// the snippet should look like " else \n " with maybe comments anywhere
	// it’s bad when there is a ‘\n’ after the “else”
	if let Some(else_snippet) = snippet_opt(cx, else_span);
	if let Some(else_pos) = else_snippet.find("else");
	if else_snippet[else_pos..].contains('\n');
	let else_desc = if is_if(else_) { "if" } else { "{..}" };

	then {
	span_note_and_lint(
	cx,
	SUSPICIOUS_ELSE_FORMATTING,
	else_span,
	&format!("this is an `else {}` but the formatting might hide it", else_desc),
	else_span,
	&format!(
	"to remove this lint, remove the `else` or remove the new line between \
	`else` and `{}`",
	else_desc,
	),
	);
	}
	}
	}

	#[must_use]
	fn has_unary_equivalent(bin_op: BinOpKind) -> bool {
	// &, *, -
	bin_op == BinOpKind::And \|\| bin_op == BinOpKind::Mul \|\| bin_op == BinOpKind::Sub
	}

	/// Implementation of the `POSSIBLE_MISSING_COMMA` lint for array
	fn check_array(cx: &EarlyContext<'_>, expr: &Expr) {
	if let ExprKind::Array(ref array) = expr.kind {
	for element in array {
	if let ExprKind::Binary(ref op, ref lhs, _) = element.kind {
	if has_unary_equivalent(op.node) && !differing_macro_contexts(lhs.span, op.span) {
	let space_span = lhs.span.between(op.span);
	if let Some(space_snippet) = snippet_opt(cx, space_span) {
	let lint_span = lhs.span.with_lo(lhs.span.hi());
	if space_snippet.contains('\n') {
	span_note_and_lint(
	cx,
	POSSIBLE_MISSING_COMMA,
	lint_span,
	"possibly missing a comma here",
	lint_span,
	"to remove this lint, add a comma or write the expr in a single line",
	);
	}
	}
	}
	}
	}
	}
	}

	fn check_missing_else(cx: &EarlyContext<'_>, first: &Expr, second: &Expr) {
	if !differing_macro_contexts(first.span, second.span)
	&& !first.span.from_expansion()
	&& is_if(first)
	&& (is_block(second) \|\| is_if(second))
	{
	// where the else would be
	let else_span = first.span.between(second.span);

	if let Some(else_snippet) = snippet_opt(cx, else_span) {
	if !else_snippet.contains('\n') {
	let (looks_like, next_thing) = if is_if(second) {
	("an `else if`", "the second `if`")
	} else {
	("an `else {..}`", "the next block")
	};

	span_note_and_lint(
	cx,
	SUSPICIOUS_ELSE_FORMATTING,
	else_span,
	&format!("this looks like {} but the `else` is missing", looks_like),
	else_span,
	&format!(
	"to remove this lint, add the missing `else` or add a new line before {}",
	next_thing,
	),
	);
	}
	}
	}
	}

	fn is_block(expr: &Expr) -> bool {
	if let ExprKind::Block(..) = expr.kind {
	true
	} else {
	false
	}
	}

	/// Check if the expression is an `if` or `if let`
	fn is_if(expr: &Expr) -> bool {
	if let ExprKind::If(..) = expr.kind {
	true
	} else {
	false
	}
	}