Auto merge of #97697 - WaffleLapkin:no_ref_vec, r=WaffleLapkin

Replace `&Vec<_>`s with `&[_]`s

It's generally preferable to use `&[_]` since it's one less indirection and it can be created from types other that `Vec`.

I've left `&Vec` in some locals where it doesn't really matter, in cases where `TypeFoldable` is expected (`TypeFoldable: Clone` so slice can't implement it) and in cases where it's `&TypeAliasThatIsActiallyVec`. Nothing important, really, I was just a little annoyed by `visit_generic_param_vec` :D

r? `@compiler-errors`

compiler/rustc_mir_transform/src/coverage/counters.rs

@@ -43,7 +43,7 @@ impl CoverageCounters {
     pub fn make_bcb_counters(
         &mut self,
         basic_coverage_blocks: &mut CoverageGraph,
-        coverage_spans: &Vec<CoverageSpan>,
+        coverage_spans: &[CoverageSpan],
     ) -> Result<Vec<CoverageKind>, Error> {
         let mut bcb_counters = BcbCounters::new(self, basic_coverage_blocks);
         bcb_counters.make_bcb_counters(coverage_spans)
@@ -349,7 +349,7 @@ impl<'a> BcbCounters<'a> {
         // counters and/or expressions of its incoming edges. This will recursively get or create
         // counters for those incoming edges first, then call `make_expression()` to sum them up,
         // with additional intermediate expressions as needed.
-        let mut predecessors = self.bcb_predecessors(bcb).clone().into_iter();
+        let mut predecessors = self.bcb_predecessors(bcb).to_owned().into_iter();
         debug!(
             "{}{:?} has multiple incoming edges and will get an expression that sums them up...",
             NESTED_INDENT.repeat(debug_indent_level),
@@ -571,12 +571,12 @@ impl<'a> BcbCounters<'a> {
     }
 
     #[inline]
-    fn bcb_predecessors(&self, bcb: BasicCoverageBlock) -> &Vec<BasicCoverageBlock> {
+    fn bcb_predecessors(&self, bcb: BasicCoverageBlock) -> &[BasicCoverageBlock] {
         &self.basic_coverage_blocks.predecessors[bcb]
     }
 
     #[inline]
-    fn bcb_successors(&self, bcb: BasicCoverageBlock) -> &Vec<BasicCoverageBlock> {
+    fn bcb_successors(&self, bcb: BasicCoverageBlock) -> &[BasicCoverageBlock] {
         &self.basic_coverage_blocks.successors[bcb]
     }
 

compiler/rustc_mir_transform/src/coverage/debug.rs

@@ -124,6 +124,7 @@ use rustc_span::Span;
 
 use std::iter;
 use std::lazy::SyncOnceCell;
+use std::ops::Deref;
 
 pub const NESTED_INDENT: &str = "    ";
 
@@ -434,11 +435,11 @@ impl GraphvizData {
     pub fn get_bcb_coverage_spans_with_counters(
         &self,
         bcb: BasicCoverageBlock,
-    ) -> Option<&Vec<(CoverageSpan, CoverageKind)>> {
+    ) -> Option<&[(CoverageSpan, CoverageKind)]> {
         if let Some(bcb_to_coverage_spans_with_counters) =
             self.some_bcb_to_coverage_spans_with_counters.as_ref()
         {
-            bcb_to_coverage_spans_with_counters.get(&bcb)
+            bcb_to_coverage_spans_with_counters.get(&bcb).map(Deref::deref)
         } else {
             None
         }
@@ -457,12 +458,9 @@ impl GraphvizData {
         }
     }
 
-    pub fn get_bcb_dependency_counters(
-        &self,
-        bcb: BasicCoverageBlock,
-    ) -> Option<&Vec<CoverageKind>> {
+    pub fn get_bcb_dependency_counters(&self, bcb: BasicCoverageBlock) -> Option<&[CoverageKind]> {
         if let Some(bcb_to_dependency_counters) = self.some_bcb_to_dependency_counters.as_ref() {
-            bcb_to_dependency_counters.get(&bcb)
+            bcb_to_dependency_counters.get(&bcb).map(Deref::deref)
         } else {
             None
         }
@@ -571,11 +569,11 @@ impl UsedExpressions {
     /// associated with a coverage span).
     pub fn validate(
         &mut self,
-        bcb_counters_without_direct_coverage_spans: &Vec<(
+        bcb_counters_without_direct_coverage_spans: &[(
             Option<BasicCoverageBlock>,
             BasicCoverageBlock,
             CoverageKind,
-        )>,
+        )],
     ) {
         if self.is_enabled() {
             let mut not_validated = bcb_counters_without_direct_coverage_spans
@@ -634,7 +632,7 @@ pub(super) fn dump_coverage_spanview<'tcx>(
     basic_coverage_blocks: &CoverageGraph,
     pass_name: &str,
     body_span: Span,
-    coverage_spans: &Vec<CoverageSpan>,
+    coverage_spans: &[CoverageSpan],
 ) {
     let mir_source = mir_body.source;
     let def_id = mir_source.def_id();
@@ -654,7 +652,7 @@ fn span_viewables<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     basic_coverage_blocks: &CoverageGraph,
-    coverage_spans: &Vec<CoverageSpan>,
+    coverage_spans: &[CoverageSpan],
 ) -> Vec<SpanViewable> {
     let mut span_viewables = Vec::new();
     for coverage_span in coverage_spans {
@@ -676,7 +674,7 @@ pub(super) fn dump_coverage_graphviz<'tcx>(
     basic_coverage_blocks: &CoverageGraph,
     debug_counters: &DebugCounters,
     graphviz_data: &GraphvizData,
-    intermediate_expressions: &Vec<CoverageKind>,
+    intermediate_expressions: &[CoverageKind],
     debug_used_expressions: &UsedExpressions,
 ) {
     let mir_source = mir_body.source;
@@ -753,9 +751,9 @@ fn bcb_to_string_sections<'tcx>(
     mir_body: &mir::Body<'tcx>,
     debug_counters: &DebugCounters,
     bcb_data: &BasicCoverageBlockData,
-    some_coverage_spans_with_counters: Option<&Vec<(CoverageSpan, CoverageKind)>>,
-    some_dependency_counters: Option<&Vec<CoverageKind>>,
-    some_intermediate_expressions: Option<&Vec<CoverageKind>>,
+    some_coverage_spans_with_counters: Option<&[(CoverageSpan, CoverageKind)]>,
+    some_dependency_counters: Option<&[CoverageKind]>,
+    some_intermediate_expressions: Option<&[CoverageKind]>,
 ) -> Vec<String> {
     let len = bcb_data.basic_blocks.len();
     let mut sections = Vec::new();