rust_typeck: remove unnecessary typing of &[] as &'static [T; 0].

Author: eddyb

src/librustc/middle/infer/error_reporting.rs

@@ -1421,7 +1421,6 @@ impl<'a, 'tcx> ErrorReportingHelpers<'tcx> for InferCtxt<'a, 'tcx> {
             infer::MiscVariable(_) => "".to_string(),
             infer::PatternRegion(_) => " for pattern".to_string(),
             infer::AddrOfRegion(_) => " for borrow expression".to_string(),
-            infer::AddrOfSlice(_) => " for slice expression".to_string(),
             infer::Autoref(_) => " for autoref".to_string(),
             infer::Coercion(_) => " for automatic coercion".to_string(),
             infer::LateBoundRegion(_, br, infer::FnCall) => {

src/librustc/middle/infer/mod.rs

@@ -249,9 +249,6 @@ pub enum RegionVariableOrigin<'tcx> {
     // Regions created by `&` operator
     AddrOfRegion(Span),
 
-    // Regions created by `&[...]` literal
-    AddrOfSlice(Span),
-
     // Regions created as part of an autoref of a method receiver
     Autoref(Span),
 
@@ -1286,7 +1283,6 @@ impl<'tcx> RegionVariableOrigin<'tcx> {
             MiscVariable(a) => a,
             PatternRegion(a) => a,
             AddrOfRegion(a) => a,
-            AddrOfSlice(a) => a,
             Autoref(a) => a,
             Coercion(ref a) => a.span(),
             EarlyBoundRegion(a, _) => a,
@@ -1309,7 +1305,6 @@ impl<'tcx> Repr<'tcx> for RegionVariableOrigin<'tcx> {
             AddrOfRegion(a) => {
                 format!("AddrOfRegion({})", a.repr(tcx))
             }
-            AddrOfSlice(a) => format!("AddrOfSlice({})", a.repr(tcx)),
             Autoref(a) => format!("Autoref({})", a.repr(tcx)),
             Coercion(ref a) => format!("Coercion({})", a.repr(tcx)),
             EarlyBoundRegion(a, b) => {

src/librustc_typeck/check/mod.rs

@@ -3600,24 +3600,8 @@ fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
             // Finally, borrowck is charged with guaranteeing that the
             // value whose address was taken can actually be made to live
             // as long as it needs to live.
-            match oprnd.node {
-                // String literals are already, implicitly converted to slices.
-                //ast::ExprLit(lit) if ast_util::lit_is_str(lit) => fcx.expr_ty(oprnd),
-                // Empty slices live in static memory.
-                ast::ExprVec(ref elements) if elements.len() == 0 => {
-                    // Note: we do not assign a lifetime of
-                    // static. This is because the resulting type
-                    // `&'static [T]` would require that T outlives
-                    // `'static`!
-                    let region = fcx.infcx().next_region_var(
-                        infer::AddrOfSlice(expr.span));
-                    ty::mk_rptr(tcx, tcx.mk_region(region), tm)
-                }
-                _ => {
-                    let region = fcx.infcx().next_region_var(infer::AddrOfRegion(expr.span));
-                    ty::mk_rptr(tcx, tcx.mk_region(region), tm)
-                }
-            }
+            let region = fcx.infcx().next_region_var(infer::AddrOfRegion(expr.span));
+            ty::mk_rptr(tcx, tcx.mk_region(region), tm)
         };
         fcx.write_ty(id, oprnd_t);
       }