address more FIXME whose associated issues were marked as closed

update FIXME(#6298) to point to open issue 15020
update FIXME(#6268) to point to RFC 811
update FIXME(#10520) to point to RFC 1751
remove FIXME for emscripten issue 4563 and include target in `test_estimate_scaling_factor`
remove FIXME(#18207) since node_id isn't used for `ref` pattern analysis
remove FIXME(#6308) since DST was implemented in #12938
remove FIXME(#2658) since it was decided to not reorganize module
remove FIXME(#20590) since it was decided to stay conservative with projection types
remove FIXME(#20297) since it was decided that solving the issue is unnecessary
remove FIXME(#27086) since closures do correspond to structs now
remove FIXME(#13846) and enable `function_sections` for windows
remove mention of #22079 in FIXME(#22079) since this is a general FIXME
remove FIXME(#5074) since the restriction on borrow were lifted

src/libcore/tests/num/flt2dec/estimator.rs

@@ -8,11 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME https://github.com/kripken/emscripten/issues/4563
-// NB we have to actually not compile this test to avoid
-// an undefined symbol error
-#![cfg(not(target_os = "emscripten"))]
-
 use core::num::flt2dec::estimator::*;
 
 #[test]

src/librustc/middle/dataflow.rs

@@ -171,7 +171,7 @@ fn build_local_id_to_index(body: Option<&hir::Body>,
                            -> FxHashMap<hir::ItemLocalId, Vec<CFGIndex>> {
     let mut index = FxHashMap();
 
-    // FIXME (#6298): Would it be better to fold formals from decl
+    // FIXME(#15020) Would it be better to fold formals from decl
     // into cfg itself?  i.e. introduce a fn-based flow-graph in
     // addition to the current block-based flow-graph, rather than
     // have to put traversals like this here?

src/librustc/middle/mem_categorization.rs

@@ -477,10 +477,8 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
 
     fn pat_ty(&self, pat: &hir::Pat) -> McResult<Ty<'tcx>> {
         let base_ty = self.node_ty(pat.hir_id)?;
-        // FIXME (Issue #18207): This code detects whether we are
+        // This code detects whether we are looking at a `ref x`,
-        // looking at a `ref x`, and if so, figures out what the type
+        // and if so, figures out what the type *being borrowed* is.
-        // *being borrowed* is.  But ideally we would put in a more
-        // fundamental fix to this conflated use of the node id.
         let ret_ty = match pat.node {
             PatKind::Binding(..) => {
                 let bm = *self.tables

src/librustc/middle/region.rs

@@ -960,7 +960,7 @@ fn resolve_expr<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>, expr:
 
             hir::ExprAssignOp(..) | hir::ExprIndex(..) |
             hir::ExprUnary(..) | hir::ExprCall(..) | hir::ExprMethodCall(..) => {
-                // FIXME(#6268) Nested method calls
+                // FIXME(https://github.com/rust-lang/rfcs/issues/811) Nested method calls
                 //
                 // The lifetimes for a call or method call look as follows:
                 //
@@ -1081,8 +1081,6 @@ fn resolve_local<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>,
     // Here, the expression `[...]` has an extended lifetime due to rule
     // A, but the inner rvalues `a()` and `b()` have an extended lifetime
     // due to rule C.
-    //
-    // FIXME(#6308) -- Note that `[]` patterns work more smoothly post-DST.
 
     if let Some(expr) = init {
         record_rvalue_scope_if_borrow_expr(visitor, &expr, blk_scope);

src/librustc/session/filesearch.rs

@@ -28,8 +28,6 @@ pub enum FileMatch {
 }
 
 // A module for searching for libraries
-// FIXME (#2658): I'm not happy how this module turned out. Should
-// probably just be folded into cstore.
 
 pub struct FileSearch<'a> {
     pub sysroot: &'a Path,

src/librustc/traits/coherence.rs

@@ -252,7 +252,6 @@ fn uncovered_tys<'tcx>(tcx: TyCtxt, ty: Ty<'tcx>, infer_is_local: InferIsLocal)
 
 fn is_type_parameter(ty: Ty) -> bool {
     match ty.sty {
-        // FIXME(#20590) straighten story about projection types
         ty::TyProjection(..) | ty::TyParam(..) => true,
         _ => false,
     }

src/librustc/traits/select.rs

@@ -1309,13 +1309,13 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         };
 
         if obligation.predicate.skip_binder().self_ty().is_ty_var() {
-            // FIXME(#20297): Self is a type variable (e.g. `_: AsRef<str>`).
+            // Self is a type variable (e.g. `_: AsRef<str>`).
             //
             // This is somewhat problematic, as the current scheme can't really
             // handle it turning to be a projection. This does end up as truly
             // ambiguous in most cases anyway.
             //
-            // Until this is fixed, take the fast path out - this also improves
+            // Take the fast path out - this also improves
             // performance by preventing assemble_candidates_from_impls from
             // matching every impl for this trait.
             return Ok(SelectionCandidateSet { vec: vec![], ambiguous: true });
@@ -1383,8 +1383,6 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     {
         debug!("assemble_candidates_for_projected_tys({:?})", obligation);
 
-        // FIXME(#20297) -- just examining the self-type is very simplistic
-
         // before we go into the whole skolemization thing, just
         // quickly check if the self-type is a projection at all.
         match obligation.predicate.0.trait_ref.self_ty().sty {
@@ -2174,14 +2172,6 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             }
 
             ty::TyClosure(def_id, ref substs) => {
-                // FIXME(#27086). We are invariant w/r/t our
-                // func_substs, but we don't see them as
-                // constituent types; this seems RIGHT but also like
-                // something that a normal type couldn't simulate. Is
-                // this just a gap with the way that PhantomData and
-                // OIBIT interact? That is, there is no way to say
-                // "make me invariant with respect to this TYPE, but
-                // do not act as though I can reach it"
                 substs.upvar_tys(def_id, self.tcx()).collect()
             }
 

src/librustc/ty/outlives.rs

@@ -73,42 +73,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // projection).
         match ty.sty {
             ty::TyClosure(def_id, ref substs) => {
-                // FIXME(#27086). We do not accumulate from substs, since they
-                // don't represent reachable data. This means that, in
-                // practice, some of the lifetime parameters might not
-                // be in scope when the body runs, so long as there is
-                // no reachable data with that lifetime. For better or
-                // worse, this is consistent with fn types, however,
-                // which can also encapsulate data in this fashion
-                // (though it's somewhat harder, and typically
-                // requires virtual dispatch).
-                //
-                // Note that changing this (in a naive way, at least)
-                // causes regressions for what appears to be perfectly
-                // reasonable code like this:
-                //
-                // ```
-                // fn foo<'a>(p: &Data<'a>) {
-                //    bar(|q: &mut Parser| q.read_addr())
-                // }
-                // fn bar(p: Box<FnMut(&mut Parser)+'static>) {
-                // }
-                // ```
-                //
-                // Note that `p` (and `'a`) are not used in the
-                // closure at all, but to meet the requirement that
-                // the closure type `C: 'static` (so it can be coerced
-                // to the object type), we get the requirement that
-                // `'a: 'static` since `'a` appears in the closure
-                // type `C`.
-                //
-                // A smarter fix might "prune" unused `func_substs` --
-                // this would avoid breaking simple examples like
-                // this, but would still break others (which might
-                // indeed be invalid, depending on your POV). Pruning
-                // would be a subtle process, since we have to see
-                // what func/type parameters are used and unused,
-                // taking into consideration UFCS and so forth.
 
                 for upvar_ty in substs.upvar_tys(def_id, *self) {
                     self.compute_components(upvar_ty, out);

src/librustc_back/target/windows_base.rs

@@ -64,8 +64,7 @@ pub fn opts() -> TargetOptions {
     ]);
 
     TargetOptions {
-        // FIXME(#13846) this should be enabled for windows
+        function_sections: true,
-        function_sections: false,
         linker: "gcc".to_string(),
         dynamic_linking: true,
         executables: true,

src/librustc_borrowck/borrowck/README.md

@@ -781,8 +781,9 @@ the base path, it will still be considered freezable.
 
 
 
-**FIXME #10520: Restrictions against mutating the base pointer.** When
+**FIXME(https://github.com/rust-lang/rfcs/issues/1751)
-an `&mut` pointer is frozen or claimed, we currently pass along the
+Restrictions against mutating the base pointer.**
+When an `&mut` pointer is frozen or claimed, we currently pass along the
 restriction against MUTATE to the base pointer. I do not believe this
 restriction is needed. It dates from the days when we had a way to
 mutate that preserved the value being mutated (i.e., swap). Nowadays

src/librustc_borrowck/borrowck/check_loans.rs

@@ -659,7 +659,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         debug!("check_if_path_is_moved(id={:?}, use_kind={:?}, lp={:?})",
                id, use_kind, lp);
 
-        // FIXME (22079): if you find yourself tempted to cut and paste
+        // FIXME: if you find yourself tempted to cut and paste
         // the body below and then specializing the error reporting,
         // consider refactoring this instead!
 
@@ -720,7 +720,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                         // the path must be initialized to prevent a case of
                         // partial reinitialization
                         //
-                        // FIXME (22079): could refactor via hypothetical
+                        // FIXME: could refactor via hypothetical
                         // generalized check_if_path_is_moved
                         let loan_path = owned_ptr_base_path_rc(lp_base);
                         self.move_data.each_move_of(id, &loan_path, |_, _| {

src/librustc_borrowck/borrowck/gather_loans/mod.rs

@@ -406,7 +406,7 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
         self.all_loans.push(loan);
 
         // if loan_gen_scope != borrow_id {
-            // FIXME(#6268) Nested method calls
+            // FIXME(https://github.com/rust-lang/rfcs/issues/811) Nested method calls
             //
             // Typically, the scope of the loan includes the point at
             // which the loan is originated. This
@@ -417,9 +417,8 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
             //let restr = restrictions::compute_restrictions(
             //    self.bccx, borrow_span, cmt, RESTR_EMPTY);
             //let loan = {
-            //    let all_loans = &mut *self.all_loans; // FIXME(#5074)
             //    Loan {
-            //        index: all_loans.len(),
+            //        index: self.all_loans.len(),
             //        loan_path,
             //        cmt,
             //        mutbl: ConstMutability,

src/librustc_typeck/check/regionck.rs

@@ -815,7 +815,8 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
                 // the type of the node expr.id here *before applying
                 // adjustments*.
                 //
-                // FIXME(#6268) nested method calls requires that this rule change
+                // FIXME(https://github.com/rust-lang/rfcs/issues/811)
+                // nested method calls requires that this rule change
                 let ty0 = self.resolve_node_type(expr.hir_id);
                 self.type_must_outlive(infer::AddrOf(expr.span), ty0, expr_region);
                 intravisit::walk_expr(self, expr);