Merge #951

951: Add name resolution to slices r=philberty a=philberty

This is the first part to support slices where we complete the name
resolution of the SliceType with its element as well as the range
expressions used in construction.

This patch also includes separation of the implementation from the
headers to try and incrementally improve build speed.

Addresses #849 

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

gcc/rust/Make-lang.in

@@ -81,6 +81,8 @@ GRS_OBJS = \
     rust/rust-ast-lower-pattern.o \
     rust/rust-ast-resolve.o \
     rust/rust-ast-resolve-pattern.o \
+    rust/rust-ast-resolve-expr.o \
+    rust/rust-ast-resolve-type.o \
     rust/rust-hir-type-check.o \
     rust/rust-tyty.o \
     rust/rust-tyctx.o \