+use crate::utils;
use crate::utils::sugg::Sugg;
use crate::utils::{match_type, paths, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
-use rustc_hir::*;
+use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, MatchSource, Mutability, PatKind, UnOp};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::hir::map::Map;
use rustc_session::{declare_lint_pass, declare_tool_lint};
-use std::marker::PhantomData;
-
declare_clippy_lint! {
/// **What it does:**
/// Lints usage of `if let Some(v) = ... { y } else { x }` which is more
///
/// ```rust
/// # let optional: Option<u32> = Some(0);
+ /// # fn do_complicated_function() -> u32 { 5 };
/// let _ = if let Some(foo) = optional {
/// foo
/// } else {
///
/// ```rust
/// # let optional: Option<u32> = Some(0);
+ /// # fn do_complicated_function() -> u32 { 5 };
/// let _ = optional.map_or(5, |foo| foo);
/// let _ = optional.map_or_else(||{
- /// let y = do_complicated_function;
+ /// let y = do_complicated_function();
/// y*y
/// }, |foo| foo);
/// ```
declare_lint_pass!(OptionIfLetElse => [OPTION_IF_LET_ELSE]);
-/// Returns true iff the given expression is the result of calling Result::ok
+/// Returns true iff the given expression is the result of calling `Result::ok`
fn is_result_ok(cx: &LateContext<'_, '_>, expr: &'_ Expr<'_>) -> bool {
- if_chain! {
- if let ExprKind::MethodCall(ref path, _, &[ref receiver]) = &expr.kind;
- if path.ident.name.to_ident_string() == "ok";
- if match_type(cx, &cx.tables.expr_ty(&receiver), &paths::RESULT);
- then {
- true
- } else {
- false
- }
+ if let ExprKind::MethodCall(ref path, _, &[ref receiver]) = &expr.kind {
+ path.ident.name.to_ident_string() == "ok" && match_type(cx, &cx.tables.expr_ty(&receiver), &paths::RESULT)
+ } else {
+ false
}
}
method_sugg: String,
some_expr: String,
none_expr: String,
+ wrap_braces: bool,
}
-struct ReturnBreakContinueVisitor<'tcx> {
+struct ReturnBreakContinueMacroVisitor {
seen_return_break_continue: bool,
- phantom_data: PhantomData<&'tcx bool>,
}
-impl<'tcx> ReturnBreakContinueVisitor<'tcx> {
- fn new() -> ReturnBreakContinueVisitor<'tcx> {
- ReturnBreakContinueVisitor {
+impl ReturnBreakContinueMacroVisitor {
+ fn new() -> ReturnBreakContinueMacroVisitor {
+ ReturnBreakContinueMacroVisitor {
seen_return_break_continue: false,
- phantom_data: PhantomData,
}
}
}
-impl<'tcx> Visitor<'tcx> for ReturnBreakContinueVisitor<'tcx> {
+impl<'tcx> Visitor<'tcx> for ReturnBreakContinueMacroVisitor {
type Map = Map<'tcx>;
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
// desugaring, as this will detect a break if there's a while loop
// or a for loop inside the expression.
_ => {
- rustc_hir::intravisit::walk_expr(self, ex);
+ if utils::in_macro(ex.span) {
+ self.seen_return_break_continue = true;
+ } else {
+ rustc_hir::intravisit::walk_expr(self, ex);
+ }
},
}
}
}
-fn contains_return_break_continue<'tcx>(expression: &'tcx Expr<'tcx>) -> bool {
- let mut recursive_visitor: ReturnBreakContinueVisitor<'tcx> = ReturnBreakContinueVisitor::new();
+fn contains_return_break_continue_macro(expression: &Expr<'_>) -> bool {
+ let mut recursive_visitor = ReturnBreakContinueMacroVisitor::new();
recursive_visitor.visit_expr(expression);
recursive_visitor.seen_return_break_continue
}
+/// Extracts the body of a given arm. If the arm contains only an expression,
+/// then it returns the expression. Otherwise, it returns the entire block
+fn extract_body_from_arm<'a>(arm: &'a Arm<'a>) -> Option<&'a Expr<'a>> {
+ if let ExprKind::Block(
+ Block {
+ stmts: statements,
+ expr: Some(expr),
+ ..
+ },
+ _,
+ ) = &arm.body.kind
+ {
+ if let [] = statements {
+ Some(&expr)
+ } else {
+ Some(&arm.body)
+ }
+ } else {
+ None
+ }
+}
+
+/// If this is the else body of an if/else expression, then we need to wrap
+/// it in curcly braces. Otherwise, we don't.
+fn should_wrap_in_braces(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
+ utils::get_enclosing_block(cx, expr.hir_id).map_or(false, |parent| {
+ if let Some(Expr {
+ kind:
+ ExprKind::Match(
+ _,
+ arms,
+ MatchSource::IfDesugar {
+ contains_else_clause: true,
+ }
+ | MatchSource::IfLetDesugar {
+ contains_else_clause: true,
+ },
+ ),
+ ..
+ }) = parent.expr
+ {
+ expr.hir_id == arms[1].body.hir_id
+ } else {
+ false
+ }
+ })
+}
+
+fn format_option_in_sugg(cx: &LateContext<'_, '_>, cond_expr: &Expr<'_>, as_ref: bool, as_mut: bool) -> String {
+ format!(
+ "{}{}",
+ Sugg::hir(cx, cond_expr, "..").maybe_par(),
+ if as_mut {
+ ".as_mut()"
+ } else if as_ref {
+ ".as_ref()"
+ } else {
+ ""
+ }
+ )
+}
+
/// If this expression is the option if let/else construct we're detecting, then
-/// this function returns an OptionIfLetElseOccurence struct with details if
+/// this function returns an `OptionIfLetElseOccurence` struct with details if
/// this construct is found, or None if this construct is not found.
fn detect_option_if_let_else<'a>(cx: &LateContext<'_, 'a>, expr: &'a Expr<'a>) -> Option<OptionIfLetElseOccurence> {
- //(String, String, String, String)> {
if_chain! {
- if let ExprKind::Match(let_body, arms, MatchSource::IfLetDesugar{contains_else_clause: true}) = &expr.kind;
+ if !utils::in_macro(expr.span); // Don't lint macros, because it behaves weirdly
+ if let ExprKind::Match(cond_expr, arms, MatchSource::IfLetDesugar{contains_else_clause: true}) = &expr.kind;
if arms.len() == 2;
- if match_type(cx, &cx.tables.expr_ty(let_body), &paths::OPTION);
- if !is_result_ok(cx, let_body); // Don't lint on Result::ok because a different lint does it already
- if let PatKind::TupleStruct(_, &[inner_pat], _) = &arms[0].pat.kind;
- if let PatKind::Binding(_, _, id, _) = &inner_pat.kind;
- if !contains_return_break_continue(arms[0].body);
- if !contains_return_break_continue(arms[1].body);
+ if !is_result_ok(cx, cond_expr); // Don't lint on Result::ok because a different lint does it already
+ if let PatKind::TupleStruct(struct_qpath, &[inner_pat], _) = &arms[0].pat.kind;
+ if utils::match_qpath(struct_qpath, &paths::OPTION_SOME);
+ if let PatKind::Binding(bind_annotation, _, id, _) = &inner_pat.kind;
+ if !contains_return_break_continue_macro(arms[0].body);
+ if !contains_return_break_continue_macro(arms[1].body);
then {
- let some_body = if let ExprKind::Block(Block { stmts: statements, expr: Some(expr), .. }, _)
- = &arms[0].body.kind {
- if let &[] = &statements {
- expr
- } else {
- &arms[0].body
- }
- } else {
- return None;
- };
- let (none_body, method_sugg) = if let ExprKind::Block(Block { stmts: statements, expr: Some(expr), .. }, _)
- = &arms[1].body.kind {
- if let &[] = &statements {
- (expr, "map_or")
- } else {
- (&arms[1].body, "map_or_else")
- }
- } else {
- return None;
+ let capture_mut = if bind_annotation == &BindingAnnotation::Mutable { "mut " } else { "" };
+ let some_body = extract_body_from_arm(&arms[0])?;
+ let none_body = extract_body_from_arm(&arms[1])?;
+ let method_sugg = match &none_body.kind {
+ ExprKind::Block(..) => "map_or_else",
+ _ => "map_or",
};
let capture_name = id.name.to_ident_string();
+ let wrap_braces = should_wrap_in_braces(cx, expr);
+ let (as_ref, as_mut) = match &cond_expr.kind {
+ ExprKind::AddrOf(_, Mutability::Not, _) => (true, false),
+ ExprKind::AddrOf(_, Mutability::Mut, _) => (false, true),
+ _ => (bind_annotation == &BindingAnnotation::Ref, bind_annotation == &BindingAnnotation::RefMut),
+ };
+ let cond_expr = match &cond_expr.kind {
+ // Pointer dereferencing happens automatically, so we can omit it in the suggestion
+ ExprKind::Unary(UnOp::UnDeref, expr) | ExprKind::AddrOf(_, _, expr) => expr,
+ _ => cond_expr,
+ };
Some(OptionIfLetElseOccurence {
- option: format!("{}", Sugg::hir(cx, let_body, "..")),
- method_sugg: format!("{}", method_sugg),
- some_expr: format!("|{}| {}", capture_name, Sugg::hir(cx, some_body, "..")),
- none_expr: format!("{}{}", if method_sugg == "map_or" { "" } else { "|| " }, Sugg::hir(cx, none_body, ".."))
+ option: format_option_in_sugg(cx, cond_expr, as_ref, as_mut),
+ method_sugg: method_sugg.to_string(),
+ some_expr: format!("|{}{}| {}", capture_mut, capture_name, Sugg::hir(cx, some_body, "..")),
+ none_expr: format!("{}{}", if method_sugg == "map_or" { "" } else { "|| " }, Sugg::hir(cx, none_body, "..")),
+ wrap_braces,
})
} else {
None
format!("use Option::{} instead of an if let/else", detection.method_sugg).as_str(),
"try",
format!(
- "{}.{}({}, {})",
- detection.option, detection.method_sugg, detection.none_expr, detection.some_expr
+ "{}{}.{}({}, {}){}",
+ if detection.wrap_braces { "{ " } else { "" },
+ detection.option,
+ detection.method_sugg,
+ detection.none_expr,
+ detection.some_expr,
+ if detection.wrap_braces { " }" } else { "" },
),
Applicability::MachineApplicable,
);
projects / rust.git / blobdiff