Fix a `manual_unwrap_or` FP with deref coercion

[rust.git] / clippy_lints / src / manual_unwrap_or.rs

diff --git a/clippy_lints/src/manual_unwrap_or.rs b/clippy_lints/src/manual_unwrap_or.rs
index 22aa37e41fec0e4124b7b3ba316c4bfc91e777f9..cf183d4c16f12a505143bc055e9136a1d0424feb 100644 (file)
--- a/clippy_lints/src/manual_unwrap_or.rs
+++ b/clippy_lints/src/manual_unwrap_or.rs
@@ -1,13 +1,19 @@
 use crate::consts::constant_simple;
-use crate::utils;
-use crate::utils::sugg;
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::{indent_of, reindent_multiline, snippet_opt};
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::usage::contains_return_break_continue_macro;
+use clippy_utils::{in_constant, is_lang_ctor, path_to_local_id, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{def, Arm, Expr, ExprKind, Pat, PatKind, QPath};
+use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
+use rustc_hir::{Arm, Expr, ExprKind, PatKind};
 use rustc_lint::LintContext;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
+use rustc_middle::ty::adjustment::Adjust;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:**
@@ -41,7 +47,7 @@
 
 impl LateLintPass<'_> for ManualUnwrapOr {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if in_external_macro(cx.sess(), expr.span) {
+        if in_external_macro(cx.sess(), expr.span) || in_constant(cx, expr.hir_id) {
             return;
         }
         lint_manual_unwrap_or(cx, expr);
@@ -64,28 +70,26 @@ fn unwrap_fn_path(&self) -> &str {
 }
 
 fn lint_manual_unwrap_or<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-    fn applicable_or_arm<'a>(arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
+    fn applicable_or_arm<'a>(cx: &LateContext<'_>, arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
         if_chain! {
             if arms.len() == 2;
             if arms.iter().all(|arm| arm.guard.is_none());
-            if let Some((idx, or_arm)) = arms.iter().enumerate().find(|(_, arm)|
+            if let Some((idx, or_arm)) = arms.iter().enumerate().find(|(_, arm)| {
                 match arm.pat.kind {
-                    PatKind::Path(ref some_qpath) =>
-                        utils::match_qpath(some_qpath, &utils::paths::OPTION_NONE),
-                    PatKind::TupleStruct(ref err_qpath, &[Pat { kind: PatKind::Wild, .. }], _) =>
-                        utils::match_qpath(err_qpath, &utils::paths::RESULT_ERR),
+                    PatKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
+                    PatKind::TupleStruct(ref qpath, &[pat], _) =>
+                        matches!(pat.kind, PatKind::Wild) && is_lang_ctor(cx, qpath, ResultErr),
                     _ => false,
                 }
-            );
+            });
             let unwrap_arm = &arms[1 - idx];
-            if let PatKind::TupleStruct(ref unwrap_qpath, &[unwrap_pat], _) = unwrap_arm.pat.kind;
-            if utils::match_qpath(unwrap_qpath, &utils::paths::OPTION_SOME)
-                || utils::match_qpath(unwrap_qpath, &utils::paths::RESULT_OK);
+            if let PatKind::TupleStruct(ref qpath, &[unwrap_pat], _) = unwrap_arm.pat.kind;
+            if is_lang_ctor(cx, qpath, OptionSome) || is_lang_ctor(cx, qpath, ResultOk);
             if let PatKind::Binding(_, binding_hir_id, ..) = unwrap_pat.kind;
-            if let ExprKind::Path(QPath::Resolved(_, body_path)) = unwrap_arm.body.kind;
-            if let def::Res::Local(body_path_hir_id) = body_path.res;
-            if body_path_hir_id == binding_hir_id;
-            if !utils::usage::contains_return_break_continue_macro(or_arm.body);
+            if path_to_local_id(unwrap_arm.body, binding_hir_id);
+            if !contains_return_break_continue_macro(or_arm.body);
+            if !cx.typeck_results().expr_adjustments(unwrap_arm.body).iter()
+                .any(|a| matches!(a.kind, Adjust::Deref(Some(..))));
             then {
                 Some(or_arm)
             } else {
@@ -97,28 +101,37 @@ fn applicable_or_arm<'a>(arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
     if_chain! {
         if let ExprKind::Match(scrutinee, match_arms, _) = expr.kind;
         let ty = cx.typeck_results().expr_ty(scrutinee);
-        if let Some(case) = if utils::is_type_diagnostic_item(cx, ty, sym!(option_type)) {
+        if let Some(case) = if is_type_diagnostic_item(cx, ty, sym::option_type) {
             Some(Case::Option)
-        } else if utils::is_type_diagnostic_item(cx, ty, sym!(result_type)) {
+        } else if is_type_diagnostic_item(cx, ty, sym::result_type) {
             Some(Case::Result)
         } else {
             None
         };
-        if let Some(or_arm) = applicable_or_arm(match_arms);
-        if let Some(or_body_snippet) = utils::snippet_opt(cx, or_arm.body.span);
-        if let Some(indent) = utils::indent_of(cx, expr.span);
+        if let Some(or_arm) = applicable_or_arm(cx, match_arms);
+        if let Some(or_body_snippet) = snippet_opt(cx, or_arm.body.span);
+        if let Some(indent) = indent_of(cx, expr.span);
         if constant_simple(cx, cx.typeck_results(), or_arm.body).is_some();
         then {
             let reindented_or_body =
-                utils::reindent_multiline(or_body_snippet.into(), true, Some(indent));
-            utils::span_lint_and_sugg(
+                reindent_multiline(or_body_snippet.into(), true, Some(indent));
+
+            let suggestion = if scrutinee.span.from_expansion() {
+                    // we don't want parenthesis around macro, e.g. `(some_macro!()).unwrap_or(0)`
+                    sugg::Sugg::hir_with_macro_callsite(cx, scrutinee, "..")
+                }
+                else {
+                    sugg::Sugg::hir(cx, scrutinee, "..").maybe_par()
+                };
+
+            span_lint_and_sugg(
                 cx,
                 MANUAL_UNWRAP_OR, expr.span,
                 &format!("this pattern reimplements `{}`", case.unwrap_fn_path()),
                 "replace with",
                 format!(
                     "{}.unwrap_or({})",
-                    sugg::Sugg::hir(cx, scrutinee, "..").maybe_par(),
+                    suggestion,
                     reindented_or_body,
                 ),
                 Applicability::MachineApplicable,