Use ?-operator in more places (clippy::question_mark, had some false negatives fixed recently)

Author: matthiaskrgr

src/libcore/str/pattern.rs

@@ -365,11 +365,7 @@ unsafe impl<'a> ReverseSearcher<'a> for CharSearcher<'a> {
         let haystack = self.haystack.as_bytes();
         loop {
             // get the haystack up to but not including the last character searched
-            let bytes = if let Some(slice) = haystack.get(self.finger..self.finger_back) {
-                slice
-            } else {
-                return None;
-            };
+            let bytes = haystack.get(self.finger..self.finger_back)?;
             // the last byte of the utf8 encoded needle
             // SAFETY: we have an invariant that `utf8_size < 5`
             let last_byte = unsafe { *self.utf8_encoded.get_unchecked(self.utf8_size - 1) };
@@ -575,11 +571,12 @@ macro_rules! pattern_methods {
 
         #[inline]
         fn is_suffix_of(self, haystack: &'a str) -> bool
-            where $t: ReverseSearcher<'a>
+        where
+            $t: ReverseSearcher<'a>,
         {
             ($pmap)(self).is_suffix_of(haystack)
         }
-    }
+    };
 }
 
 macro_rules! searcher_methods {
@@ -614,7 +611,7 @@ macro_rules! searcher_methods {
         fn next_reject_back(&mut self) -> Option<(usize, usize)> {
             self.0.next_reject_back()
         }
-    }
+    };
 }
 
 /////////////////////////////////////////////////////////////////////////////

src/librustc/hir/map/mod.rs

@@ -298,7 +298,7 @@ impl<'hir> Map<'hir> {
     }
 
     pub fn def_kind(&self, hir_id: HirId) -> Option<DefKind> {
-        let node = if let Some(node) = self.find(hir_id) { node } else { return None };
+        let node = self.find(hir_id)?;
 
         Some(match node {
             Node::Item(item) => match item.kind {

src/librustc/ty/util.rs

@@ -346,12 +346,7 @@ impl<'tcx> TyCtxt<'tcx> {
         adt_did: DefId,
         validate: &mut dyn FnMut(Self, DefId) -> Result<(), ErrorReported>,
     ) -> Option<ty::Destructor> {
-        let drop_trait = if let Some(def_id) = self.lang_items().drop_trait() {
-            def_id
-        } else {
-            return None;
-        };
-
+        let drop_trait = self.lang_items().drop_trait()?;
         self.ensure().coherent_trait(drop_trait);
 
         let mut dtor_did = None;

src/librustc_driver/lib.rs

@@ -1120,12 +1120,7 @@ fn extra_compiler_flags() -> Option<(Vec<String>, bool)> {
         return None;
     }
 
-    let matches = if let Some(matches) = handle_options(&args) {
-        matches
-    } else {
-        return None;
-    };
-
+    let matches = handle_options(&args)?;
     let mut result = Vec::new();
     let mut excluded_cargo_defaults = false;
     for flag in ICE_REPORT_COMPILER_FLAGS {

src/librustc_infer/traits/specialize/mod.rs

@@ -413,12 +413,7 @@ pub(super) fn specialization_graph_provider(
 fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Option<String> {
     use std::fmt::Write;
 
-    let trait_ref = if let Some(tr) = tcx.impl_trait_ref(impl_def_id) {
-        tr
-    } else {
-        return None;
-    };
-
+    let trait_ref = tcx.impl_trait_ref(impl_def_id)?;
     let mut w = "impl".to_owned();
 
     let substs = InternalSubsts::identity_for_item(tcx, impl_def_id);

src/librustc_resolve/lib.rs

@@ -2778,12 +2778,8 @@ impl<'a> Resolver<'a> {
             } else {
                 let crate_id = if !speculative {
                     self.crate_loader.process_path_extern(ident.name, ident.span)
-                } else if let Some(crate_id) =
-                    self.crate_loader.maybe_process_path_extern(ident.name, ident.span)
-                {
-                    crate_id
                 } else {
-                    return None;
+                    self.crate_loader.maybe_process_path_extern(ident.name, ident.span)?
                 };
                 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
                 Some(

src/librustc_span/lib.rs

@@ -1167,11 +1167,7 @@ impl SourceFile {
         }
 
         let begin = {
-            let line = if let Some(line) = self.lines.get(line_number) {
-                line
-            } else {
-                return None;
-            };
+            let line = self.lines.get(line_number)?;
             let begin: BytePos = *line - self.start_pos;
             begin.to_usize()
         };

src/librustdoc/clean/inline.rs

@@ -42,11 +42,7 @@ pub fn try_inline(
     attrs: Option<Attrs<'_>>,
     visited: &mut FxHashSet<DefId>,
 ) -> Option<Vec<clean::Item>> {
-    let did = if let Some(did) = res.opt_def_id() {
-        did
-    } else {
-        return None;
-    };
+    let did = res.opt_def_id()?;
     if did.is_local() {
         return None;
     }

src/librustdoc/html/markdown.rs

@@ -844,11 +844,7 @@ pub fn plain_summary_line(md: &str) -> String {
         type Item = String;
 
         fn next(&mut self) -> Option<String> {
-            let next_event = self.inner.next();
-            if next_event.is_none() {
-                return None;
-            }
-            let next_event = next_event.unwrap();
+            let next_event = self.inner.next()?;
             let (ret, is_in) = match next_event {
                 Event::Start(Tag::Paragraph) => (None, 1),
                 Event::Start(Tag::Heading(_)) => (None, 1),