Spellchecking some comments

This PR attempts to clean up some minor spelling mistakes in comments

Author: nyurik

compiler/rustc_apfloat/src/ieee.rs

@@ -461,7 +461,7 @@ impl<S: Semantics> fmt::Display for IeeeFloat<S> {
                 (combined / 10) as u32 as Limb
             });
 
-            // Reduce the sigificand to avoid wasting time dividing 0's.
+            // Reduce the significand to avoid wasting time dividing 0's.
             while sig.last() == Some(&0) {
                 sig.pop();
             }

compiler/rustc_ast_lowering/src/lib.rs

@@ -634,7 +634,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // This can happen when trying to lower the return type `x` in erroneous code like
         //   async fn foo(x: u8) -> x {}
         // In that case, `x` is lowered as a function parameter, and the return type is lowered as
-        // an opaque type as a synthetized HIR owner.
+        // an opaque type as a synthesized HIR owner.
         res.unwrap_or(Res::Err)
     }
 

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -622,7 +622,7 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    /// Reject C-varadic type unless the function is foreign,
+    /// Reject C-variadic type unless the function is foreign,
     /// or free and `unsafe extern "C"` semantically.
     fn check_c_varadic_type(&self, fk: FnKind<'a>) {
         match (fk.ctxt(), fk.header()) {

compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs

@@ -55,7 +55,7 @@ impl OutlivesSuggestionBuilder {
             | RegionNameSource::NamedFreeRegion(..)
             | RegionNameSource::Static => true,
 
-            // Don't give suggestions for upvars, closure return types, or other unnamable
+            // Don't give suggestions for upvars, closure return types, or other unnameable
             // regions.
             RegionNameSource::SynthesizedFreeEnvRegion(..)
             | RegionNameSource::AnonRegionFromArgument(..)

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -176,7 +176,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         // FIXME. We should handle this case better. It
                         // indicates that we have e.g., some region variable
                         // whose value is like `'a+'b` where `'a` and `'b` are
-                        // distinct unrelated univesal regions that are not
+                        // distinct unrelated universal regions that are not
                         // known to outlive one another. It'd be nice to have
                         // some examples where this arises to decide how best
                         // to report it; we could probably handle it by

compiler/rustc_borrowck/src/invalidation.rs

@@ -365,7 +365,7 @@ impl<'cx, 'tcx> InvalidationGenerator<'cx, 'tcx> {
                     // borrow); so don't check if they interfere.
                     //
                     // NOTE: *reservations* do conflict with themselves;
-                    // thus aren't injecting unsoundenss w/ this check.)
+                    // thus aren't injecting unsoundness w/ this check.)
                     (Activation(_, activating), _) if activating == borrow_index => {
                         // Activating a borrow doesn't generate any invalidations, since we
                         // have already taken the reservation

compiler/rustc_borrowck/src/lib.rs

@@ -1046,7 +1046,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // borrow); so don't check if they interfere.
                 //
                 // NOTE: *reservations* do conflict with themselves;
-                // thus aren't injecting unsoundenss w/ this check.)
+                // thus aren't injecting unsoundness w/ this check.)
                 (Activation(_, activating), _) if activating == borrow_index => {
                     debug!(
                         "check_access_for_conflict place_span: {:?} sd: {:?} rw: {:?} \
@@ -1105,7 +1105,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     );
                     // rust-lang/rust#56254 - This was previously permitted on
                     // the 2018 edition so we emit it as a warning. We buffer
-                    // these sepately so that we only emit a warning if borrow
+                    // these separately so that we only emit a warning if borrow
                     // checking was otherwise successful.
                     this.reservation_warnings
                         .insert(bi, (place_span.0, place_span.1, location, bk, borrow.clone()));
@@ -1586,7 +1586,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ) {
         debug!("check_if_reassignment_to_immutable_state({:?})", local);
 
-        // Check if any of the initializiations of `local` have happened yet:
+        // Check if any of the initializations of `local` have happened yet:
         if let Some(init_index) = self.is_local_ever_initialized(local, flow_state) {
             // And, if so, report an error.
             let init = &self.move_data.inits[init_index];

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -787,7 +787,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let universe_a = self.scc_universes[scc_a];
 
         // Quick check: if scc_b's declared universe is a subset of
-        // scc_a's declared univese (typically, both are ROOT), then
+        // scc_a's declared universe (typically, both are ROOT), then
         // it cannot contain any problematic universe elements.
         if universe_a.can_name(self.scc_universes[scc_b]) {
             return true;
@@ -1991,7 +1991,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             .iter()
             .find_map(|constraint| {
                 if let ConstraintCategory::Predicate(predicate_span) = constraint.category {
-                    // We currentl'y doesn't store the `DefId` in the `ConstraintCategory`
+                    // We currently do not store the `DefId` in the `ConstraintCategory`
                     // for performances reasons. The error reporting code used by NLL only
                     // uses the span, so this doesn't cause any problems at the moment.
                     Some(ObligationCauseCode::BindingObligation(

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2640,7 +2640,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             // we have to solve them here where we instantiate the
             // closure.
             //
-            // Despite the opacity of the previous parapgrah, this is
+            // Despite the opacity of the previous paragraph, this is
             // actually relatively easy to understand in terms of the
             // desugaring. A closure gets desugared to a struct, and
             // these extra requirements are basically like where

compiler/rustc_builtin_macros/src/cfg_eval.rs

@@ -137,7 +137,7 @@ impl CfgEval<'_, '_> {
         }
 
         // The majority of parsed attribute targets will never need to have early cfg-expansion
-        // run (e.g. they are not part of a `#[derive]` or `#[cfg_eval]` macro inoput).
+        // run (e.g. they are not part of a `#[derive]` or `#[cfg_eval]` macro input).
         // Therefore, we normally do not capture the necessary information about `#[cfg]`
         // and `#[cfg_attr]` attributes during parsing.
         //