diff --git a/src/Cargo.lock b/src/Cargo.lock
index b34007db8ac7a..a9a6fabb5b23c 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -27,7 +27,7 @@ version = "0.0.0"
 dependencies = [
  "build_helper 0.1.0",
  "core 0.0.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.0.0",
 ]
 
@@ -48,6 +48,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "arena"
 version = "0.0.0"
 
+[[package]]
+name = "atty"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "0.5.0"
@@ -55,7 +65,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "bitflags"
-version = "0.7.0"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -65,11 +75,11 @@ dependencies = [
  "build_helper 0.1.0",
  "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.1.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -77,7 +87,7 @@ dependencies = [
 name = "build-manifest"
 version = "0.1.0"
 dependencies = [
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.1.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -94,17 +104,17 @@ version = "0.1.0"
 
 [[package]]
 name = "clap"
-version = "2.20.5"
+version = "2.21.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "term_size 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-segmentation 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "vec_map 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vec_map 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -112,7 +122,7 @@ name = "cmake"
 version = "0.1.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -130,7 +140,7 @@ version = "0.0.0"
 dependencies = [
  "build_helper 0.1.0",
  "core 0.0.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -140,7 +150,7 @@ dependencies = [
  "env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -186,7 +196,7 @@ name = "flate"
 version = "0.0.0"
 dependencies = [
  "build_helper 0.1.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -195,7 +205,7 @@ version = "0.0.0"
 
 [[package]]
 name = "gcc"
-version = "0.3.43"
+version = "0.3.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -221,7 +231,7 @@ dependencies = [
  "pest 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 0.9.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -274,7 +284,7 @@ name = "mdbook"
 version = "0.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "clap 2.20.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.21.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "handlebars 0.25.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -397,11 +407,28 @@ name = "regex-syntax"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "rls-data"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rls-span 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rls-span"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rustbook"
 version = "0.1.0"
 dependencies = [
- "clap 2.20.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.21.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "mdbook 0.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -435,7 +462,7 @@ dependencies = [
 
 [[package]]
 name = "rustc-serialize"
-version = "0.3.22"
+version = "0.3.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -577,7 +604,7 @@ name = "rustc_llvm"
 version = "0.0.0"
 dependencies = [
  "build_helper 0.1.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_bitflags 0.0.0",
 ]
 
@@ -690,8 +717,10 @@ name = "rustc_save_analysis"
 version = "0.0.0"
 dependencies = [
  "log 0.0.0",
+ "rls-data 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "serialize 0.0.0",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "syntax 0.0.0",
  "syntax_pos 0.0.0",
 ]
@@ -751,7 +780,7 @@ version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
  "build_helper 0.1.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.0.0",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
@@ -799,7 +828,7 @@ dependencies = [
  "collections 0.0.0",
  "compiler_builtins 0.0.0",
  "core 0.0.0",
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.0.0",
  "panic_abort 0.0.0",
  "panic_unwind 0.0.0",
@@ -904,7 +933,7 @@ name = "toml"
 version = "0.1.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -940,7 +969,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "vec_map"
-version = "0.6.0"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -961,15 +990,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [metadata]
 "checksum aho-corasick 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0638fd549427caa90c499814196d1b9e3725eb4d15d7339d6de073a680ed0ca2"
 "checksum ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "23ac7c30002a5accbf7e8987d0632fa6de155b7c3d39d0067317a391e00a2ef6"
+"checksum atty 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d912da0db7fa85514874458ca3651fe2cddace8d0b0505571dbdcd41ab490159"
 "checksum bitflags 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4f67931368edf3a9a51d29886d245f1c3db2f1ef0dcc9e35ff70341b78c10d23"
-"checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
-"checksum clap 2.20.5 (registry+https://github.com/rust-lang/crates.io-index)" = "7db281b0520e97fbd15cd615dcd8f8bcad0c26f5f7d5effe705f090f39e9a758"
+"checksum bitflags 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e1ab483fc81a8143faa7203c4a3c02888ebd1a782e37e41fa34753ba9a162"
+"checksum clap 2.21.1 (registry+https://github.com/rust-lang/crates.io-index)" = "74a80f603221c9cd9aa27a28f52af452850051598537bb6b359c38a7d61e5cda"
 "checksum cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "e1acc68a3f714627af38f9f5d09706a28584ba60dfe2cca68f40bf779f941b25"
 "checksum dtoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "80c8b71fd71146990a9742fc06dcbbde19161a267e0ad4e572c35162f4578c90"
 "checksum env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "15abd780e45b3ea4f76b4e9a26ff4843258dd8a3eed2775a0e7368c2e7936c2f"
 "checksum env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e3856f1697098606fc6cb97a93de88ca3f3bc35bb878c725920e6e82ecf05e83"
 "checksum filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "5363ab8e4139b8568a6237db5248646e5a8a2f89bd5ccb02092182b11fd3e922"
-"checksum gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)" = "c07c758b972368e703a562686adb39125707cc1ef3399da8c019fc6c2498a75d"
+"checksum gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)" = "a32cd40070d7611ab76343dcb3204b2bb28c8a9450989a83a3d590248142f439"
 "checksum getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9047cfbd08a437050b363d35ef160452c5fe8ea5187ae0a624708c91581d685"
 "checksum handlebars 0.25.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b2249f6f0dc5a3bb2b3b1a8f797dfccbc4b053344d773d654ad565e51427d335"
 "checksum itoa 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "eb2f404fbc66fd9aac13e998248505e7ecb2ad8e44ab6388684c5fb11c6c251c"
@@ -987,7 +1017,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0aad603e8d7fb67da22dbdf1f4b826ce8829e406124109e73cf1b2454b93a71c"
 "checksum regex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4278c17d0f6d62dfef0ab00028feb45bd7d2102843f80763474eeb1be8a10c01"
 "checksum regex-syntax 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9191b1f57603095f105d317e375d19b1c9c5c3185ea9633a99a6dcbed04457"
-"checksum rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "237546c689f20bb44980270c73c3b9edd0891c1be49cc1274406134a66d3957b"
+"checksum rls-data 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "af1dfff00189fd7b78edb9af131b0de703676c04fa8126aed77fd2c586775a4d"
+"checksum rls-span 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8656f7b850ac85fb204ef94318c641bbb15a32766e12f9a589a23e4c0fbc38db"
+"checksum rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)" = "684ce48436d6465300c9ea783b6b14c4361d6b8dcbb1375b486a69cc19e2dfb0"
 "checksum serde 0.9.11 (registry+https://github.com/rust-lang/crates.io-index)" = "a702319c807c016e51f672e5c77d6f0b46afddd744b5e437d6b8436b888b458f"
 "checksum serde_json 0.9.9 (registry+https://github.com/rust-lang/crates.io-index)" = "dbc45439552eb8fb86907a2c41c1fd0ef97458efb87ff7f878db466eb581824e"
 "checksum strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b4d15c810519a91cf877e7e36e63fe068815c678181439f2f29e2562147c3694"
@@ -1000,7 +1032,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "bf3a113775714a22dcb774d8ea3655c53a32debae63a063acc00a91cc586245f"
 "checksum unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1f2ae5ddb18e1c92664717616dd9549dde73f539f01bd7b77c2edb2446bdff91"
 "checksum utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "662fab6525a98beff2921d7f61a39e7d59e0b425ebc7d0d9e66d316e55124122"
-"checksum vec_map 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cac5efe5cb0fa14ec2f84f83c701c562ee63f6dcc680861b21d65c682adfb05f"
+"checksum vec_map 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f8cdc8b93bd0198ed872357fb2e667f7125646b1762f16d60b2c96350d361897"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index ba85e81ff4fc4..62b7f6cb72e3b 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -94,6 +94,13 @@ fn main() {
             cmd.arg("-Cprefer-dynamic");
         }
 
+        // Pass the `rustbuild` feature flag to crates which rustbuild is
+        // building. See the comment in bootstrap/lib.rs where this env var is
+        // set for more details.
+        if env::var_os("RUSTBUILD_UNSTABLE").is_some() {
+            cmd.arg("--cfg").arg("rustbuild");
+        }
+
         // Help the libc crate compile by assisting it in finding the MUSL
         // native libraries.
         if let Some(s) = env::var_os("MUSL_ROOT") {
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 270cb8490d9a7..26f3c06306197 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -180,7 +180,7 @@ struct Crate {
 ///
 /// These entries currently correspond to the various output directories of the
 /// build system, with each mod generating output in a different directory.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, PartialEq, Eq)]
 pub enum Mode {
     /// This cargo is going to build the standard library, placing output in the
     /// "stageN-std" directory.
@@ -491,7 +491,7 @@ impl Build {
         // For other crates, however, we know that we've already got a standard
         // library up and running, so we can use the normal compiler to compile
         // build scripts in that situation.
-        if let Mode::Libstd = mode {
+        if mode == Mode::Libstd {
             cargo.env("RUSTC_SNAPSHOT", &self.rustc)
                  .env("RUSTC_SNAPSHOT_LIBDIR", self.rustc_snapshot_libdir());
         } else {
@@ -499,6 +499,27 @@ impl Build {
                  .env("RUSTC_SNAPSHOT_LIBDIR", self.rustc_libdir(compiler));
         }
 
+        // There are two invariants we try must maintain:
+        // * stable crates cannot depend on unstable crates (general Rust rule),
+        // * crates that end up in the sysroot must be unstable (rustbuild rule).
+        //
+        // In order to do enforce the latter, we pass the env var
+        // `RUSTBUILD_UNSTABLE` down the line for any crates which will end up
+        // in the sysroot. We read this in bootstrap/bin/rustc.rs and if it is
+        // set, then we pass the `rustbuild` feature to rustc when building the
+        // the crate.
+        //
+        // In turn, crates that can be used here should recognise the `rustbuild`
+        // feature and opt-in to `rustc_private`.
+        //
+        // We can't always pass `rustbuild` because crates which are outside of
+        // the comipiler, libs, and tests are stable and we don't want to make
+        // their deps unstable (since this would break the first invariant
+        // above).
+        if mode != Mode::Tool {
+            cargo.env("RUSTBUILD_UNSTABLE", "1");
+        }
+
         // Ignore incremental modes except for stage0, since we're
         // not guaranteeing correctness acros builds if the compiler
         // is changing under your feet.`
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index 3d66e5a300787..06c5150fd13ad 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -12,5 +12,8 @@ crate-type = ["dylib"]
 log = { path = "../liblog" }
 rustc = { path = "../librustc" }
 syntax = { path = "../libsyntax" }
-serialize = { path = "../libserialize" }
-syntax_pos = { path = "../libsyntax_pos" }
\ No newline at end of file
+syntax_pos = { path = "../libsyntax_pos" }
+rls-data = "0.1"
+rls-span = "0.1"
+# FIXME(#40527) should move rustc serialize out of tree
+rustc-serialize = "0.3"
diff --git a/src/librustc_save_analysis/csv_dumper.rs b/src/librustc_save_analysis/csv_dumper.rs
index 0fd95500422ff..59340ae87ee5d 100644
--- a/src/librustc_save_analysis/csv_dumper.rs
+++ b/src/librustc_save_analysis/csv_dumper.rs
@@ -13,6 +13,8 @@ use std::io::Write;
 use super::external_data::*;
 use super::dump::Dump;
 
+use rls_data::{SpanData, CratePreludeData};
+
 pub struct CsvDumper<'b, W: 'b> {
     output: &'b mut W
 }
@@ -429,6 +431,6 @@ fn make_values_str(pairs: &[(&'static str, &str)]) -> String {
 fn span_extent_str(span: SpanData) -> String {
     format!("file_name,\"{}\",file_line,{},file_col,{},byte_start,{},\
              file_line_end,{},file_col_end,{},byte_end,{}",
-             span.file_name, span.line_start, span.column_start, span.byte_start,
-             span.line_end, span.column_end, span.byte_end)
+             span.file_name.to_str().unwrap(), span.line_start.0, span.column_start.0,
+             span.byte_start, span.line_end.0, span.column_end.0, span.byte_end)
 }
diff --git a/src/librustc_save_analysis/data.rs b/src/librustc_save_analysis/data.rs
index 6caf81380e40d..d4ded71a33390 100644
--- a/src/librustc_save_analysis/data.rs
+++ b/src/librustc_save_analysis/data.rs
@@ -18,6 +18,8 @@ use rustc::hir::def_id::{CrateNum, DefId};
 use syntax::ast::{self, Attribute, NodeId};
 use syntax_pos::Span;
 
+use rls_data::ExternalCrateData;
+
 pub struct CrateData {
     pub name: String,
     pub number: u32,
@@ -26,7 +28,7 @@ pub struct CrateData {
 
 /// Data for any entity in the Rust language. The actual data contained varies
 /// with the kind of entity being queried. See the nested structs for details.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub enum Data {
     /// Data for Enums.
     EnumData(EnumData),
@@ -77,7 +79,7 @@ pub enum Data {
     VariableRefData(VariableRefData),
 }
 
-#[derive(Eq, PartialEq, Clone, Copy, Debug, RustcEncodable)]
+#[derive(Eq, PartialEq, Clone, Copy, Debug)]
 pub enum Visibility {
     Public,
     Restricted,
@@ -107,7 +109,7 @@ impl<'a> From<&'a hir::Visibility> for Visibility {
 }
 
 /// Data for the prelude of a crate.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct CratePreludeData {
     pub crate_name: String,
     pub crate_root: String,
@@ -115,16 +117,8 @@ pub struct CratePreludeData {
     pub span: Span,
 }
 
-/// Data for external crates in the prelude of a crate.
-#[derive(Debug, RustcEncodable)]
-pub struct ExternalCrateData {
-    pub name: String,
-    pub num: CrateNum,
-    pub file_name: String,
-}
-
 /// Data for enum declarations.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct EnumData {
     pub id: NodeId,
     pub name: String,
@@ -140,7 +134,7 @@ pub struct EnumData {
 }
 
 /// Data for extern crates.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ExternCrateData {
     pub id: NodeId,
     pub name: String,
@@ -151,7 +145,7 @@ pub struct ExternCrateData {
 }
 
 /// Data about a function call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct FunctionCallData {
     pub span: Span,
     pub scope: NodeId,
@@ -159,7 +153,7 @@ pub struct FunctionCallData {
 }
 
 /// Data for all kinds of functions and methods.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct FunctionData {
     pub id: NodeId,
     pub name: String,
@@ -176,14 +170,14 @@ pub struct FunctionData {
 }
 
 /// Data about a function call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct FunctionRefData {
     pub span: Span,
     pub scope: NodeId,
     pub ref_id: DefId,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ImplData {
     pub id: NodeId,
     pub span: Span,
@@ -192,7 +186,7 @@ pub struct ImplData {
     pub self_ref: Option<DefId>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 // FIXME: this struct should not exist. However, removing it requires heavy
 // refactoring of dump_visitor.rs. See PR 31838 for more info.
 pub struct ImplData2 {
@@ -206,7 +200,7 @@ pub struct ImplData2 {
     pub self_ref: Option<TypeRefData>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct InheritanceData {
     pub span: Span,
     pub base_id: DefId,
@@ -214,7 +208,7 @@ pub struct InheritanceData {
 }
 
 /// Data about a macro declaration.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MacroData {
     pub span: Span,
     pub name: String,
@@ -223,7 +217,7 @@ pub struct MacroData {
 }
 
 /// Data about a macro use.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MacroUseData {
     pub span: Span,
     pub name: String,
@@ -236,7 +230,7 @@ pub struct MacroUseData {
 }
 
 /// Data about a method call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MethodCallData {
     pub span: Span,
     pub scope: NodeId,
@@ -245,7 +239,7 @@ pub struct MethodCallData {
 }
 
 /// Data for method declarations (methods with a body are treated as functions).
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct MethodData {
     pub id: NodeId,
     pub name: String,
@@ -262,7 +256,7 @@ pub struct MethodData {
 }
 
 /// Data for modules.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ModData {
     pub id: NodeId,
     pub name: String,
@@ -278,7 +272,7 @@ pub struct ModData {
 }
 
 /// Data for a reference to a module.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ModRefData {
     pub span: Span,
     pub scope: NodeId,
@@ -286,7 +280,7 @@ pub struct ModRefData {
     pub qualname: String
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct StructData {
     pub span: Span,
     pub name: String,
@@ -302,7 +296,7 @@ pub struct StructData {
     pub attributes: Vec<Attribute>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct StructVariantData {
     pub span: Span,
     pub name: String,
@@ -317,7 +311,7 @@ pub struct StructVariantData {
     pub attributes: Vec<Attribute>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TraitData {
     pub span: Span,
     pub id: NodeId,
@@ -332,7 +326,7 @@ pub struct TraitData {
     pub attributes: Vec<Attribute>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TupleVariantData {
     pub span: Span,
     pub id: NodeId,
@@ -348,7 +342,7 @@ pub struct TupleVariantData {
 }
 
 /// Data for a typedef.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TypeDefData {
     pub id: NodeId,
     pub name: String,
@@ -363,7 +357,7 @@ pub struct TypeDefData {
 }
 
 /// Data for a reference to a type or trait.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct TypeRefData {
     pub span: Span,
     pub scope: NodeId,
@@ -371,7 +365,7 @@ pub struct TypeRefData {
     pub qualname: String,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct UseData {
     pub id: NodeId,
     pub span: Span,
@@ -381,7 +375,7 @@ pub struct UseData {
     pub visibility: Visibility,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct UseGlobData {
     pub id: NodeId,
     pub span: Span,
@@ -391,7 +385,7 @@ pub struct UseGlobData {
 }
 
 /// Data for local and global variables (consts and statics).
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct VariableData {
     pub id: NodeId,
     pub kind: VariableKind,
@@ -408,7 +402,7 @@ pub struct VariableData {
     pub attributes: Vec<Attribute>,
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub enum VariableKind {
     Static,
     Const,
@@ -418,7 +412,7 @@ pub enum VariableKind {
 
 /// Data for the use of some item (e.g., the use of a local variable, which
 /// will refer to that variables declaration (by ref_id)).
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct VariableRefData {
     pub name: String,
     pub span: Span,
@@ -430,7 +424,7 @@ pub struct VariableRefData {
 /// Encodes information about the signature of a definition. This should have
 /// enough information to create a nice display about a definition without
 /// access to the source code.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct Signature {
     pub span: Span,
     pub text: String,
@@ -444,7 +438,7 @@ pub struct Signature {
 
 /// An element of a signature. `start` and `end` are byte offsets into the `text`
 /// of the parent `Signature`.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct SigElement {
     pub id: DefId,
     pub start: usize,
diff --git a/src/librustc_save_analysis/dump.rs b/src/librustc_save_analysis/dump.rs
index 18241b394cc17..84e1fb03f624e 100644
--- a/src/librustc_save_analysis/dump.rs
+++ b/src/librustc_save_analysis/dump.rs
@@ -10,6 +10,8 @@
 
 use super::external_data::*;
 
+use rls_data::CratePreludeData;
+
 pub trait Dump {
     fn crate_prelude(&mut self, CratePreludeData) {}
     fn enum_data(&mut self, EnumData) {}
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index 61956e5cd9d66..f2aa89ba4b66e 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -29,7 +29,7 @@
 
 use rustc::hir;
 use rustc::hir::def::Def;
-use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::hir::map::{Node, NodeItem};
 use rustc::session::Session;
 use rustc::ty::{self, TyCtxt, AssociatedItemContainer};
@@ -54,6 +54,8 @@ use super::external_data::{Lower, make_def_id};
 use super::span_utils::SpanUtils;
 use super::recorder;
 
+use rls_data::ExternalCrateData;
+
 macro_rules! down_cast_data {
     ($id:ident, $kind:ident, $sp:expr) => {
         let $id = if let super::Data::$kind(data) = $id {
@@ -137,7 +139,7 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
             let lo_loc = self.span.sess.codemap().lookup_char_pos(c.span.lo);
             ExternalCrateData {
                 name: c.name,
-                num: CrateNum::from_u32(c.number),
+                num: c.number,
                 file_name: SpanUtils::make_path_string(&lo_loc.file.name),
             }
         }).collect();
diff --git a/src/librustc_save_analysis/external_data.rs b/src/librustc_save_analysis/external_data.rs
index f038c2dc298ad..6fd2de97767e1 100644
--- a/src/librustc_save_analysis/external_data.rs
+++ b/src/librustc_save_analysis/external_data.rs
@@ -18,6 +18,9 @@ use syntax_pos::Span;
 
 use data::{self, Visibility, SigElement};
 
+use rls_data::{SpanData, CratePreludeData, Attribute};
+use rls_span::{Column, Row};
+
 // FIXME: this should be pub(crate), but the current snapshot doesn't allow it yet
 pub trait Lower {
     type Target;
@@ -35,41 +38,19 @@ pub fn null_def_id() -> DefId {
     }
 }
 
-#[derive(Clone, Debug, RustcEncodable)]
-pub struct SpanData {
-    pub file_name: String,
-    pub byte_start: u32,
-    pub byte_end: u32,
-    /// 1-based.
-    pub line_start: usize,
-    pub line_end: usize,
-    /// 1-based, character offset.
-    pub column_start: usize,
-    pub column_end: usize,
-}
-
-impl SpanData {
-    pub fn from_span(span: Span, cm: &CodeMap) -> SpanData {
-        let start = cm.lookup_char_pos(span.lo);
-        let end = cm.lookup_char_pos(span.hi);
-
-        SpanData {
-            file_name: start.file.name.clone(),
-            byte_start: span.lo.0,
-            byte_end: span.hi.0,
-            line_start: start.line,
-            line_end: end.line,
-            column_start: start.col.0 + 1,
-            column_end: end.col.0 + 1,
-        }
-    }
-}
+pub fn span_from_span(span: Span, cm: &CodeMap) -> SpanData {
+    let start = cm.lookup_char_pos(span.lo);
+    let end = cm.lookup_char_pos(span.hi);
 
-/// Represent an arbitrary attribute on a code element
-#[derive(Clone, Debug, RustcEncodable)]
-pub struct Attribute {
-    value: String,
-    span: SpanData,
+    SpanData {
+        file_name: start.file.name.clone().into(),
+        byte_start: span.lo.0,
+        byte_end: span.hi.0,
+        line_start: Row::new_one_indexed(start.line as u32),
+        line_end: Row::new_one_indexed(end.line as u32),
+        column_start: Column::new_one_indexed(start.col.0 as u32 + 1),
+        column_end: Column::new_one_indexed(end.col.0 as u32 + 1),
+    }
 }
 
 impl Lower for Vec<ast::Attribute> {
@@ -91,20 +72,12 @@ impl Lower for Vec<ast::Attribute> {
 
             Attribute {
                 value: value,
-                span: SpanData::from_span(attr.span, tcx.sess.codemap()),
+                span: span_from_span(attr.span, tcx.sess.codemap()),
             }
         }).collect()
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-pub struct CratePreludeData {
-    pub crate_name: String,
-    pub crate_root: String,
-    pub external_crates: Vec<data::ExternalCrateData>,
-    pub span: SpanData,
-}
-
 impl Lower for data::CratePreludeData {
     type Target = CratePreludeData;
 
@@ -113,13 +86,13 @@ impl Lower for data::CratePreludeData {
             crate_name: self.crate_name,
             crate_root: self.crate_root,
             external_crates: self.external_crates,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
         }
     }
 }
 
 /// Data for enum declarations.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct EnumData {
     pub id: DefId,
     pub value: String,
@@ -143,7 +116,7 @@ impl Lower for data::EnumData {
             name: self.name,
             value: self.value,
             qualname: self.qualname,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             variants: self.variants.into_iter().map(|id| make_def_id(id, &tcx.hir)).collect(),
             visibility: self.visibility,
@@ -155,7 +128,7 @@ impl Lower for data::EnumData {
 }
 
 /// Data for extern crates.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ExternCrateData {
     pub id: DefId,
     pub name: String,
@@ -174,14 +147,14 @@ impl Lower for data::ExternCrateData {
             name: self.name,
             crate_num: self.crate_num,
             location: self.location,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
         }
     }
 }
 
 /// Data about a function call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct FunctionCallData {
     pub span: SpanData,
     pub scope: DefId,
@@ -193,7 +166,7 @@ impl Lower for data::FunctionCallData {
 
     fn lower(self, tcx: TyCtxt) -> FunctionCallData {
         FunctionCallData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
         }
@@ -201,7 +174,7 @@ impl Lower for data::FunctionCallData {
 }
 
 /// Data for all kinds of functions and methods.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct FunctionData {
     pub id: DefId,
     pub name: String,
@@ -226,7 +199,7 @@ impl Lower for data::FunctionData {
             name: self.name,
             qualname: self.qualname,
             declaration: self.declaration,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             value: self.value,
             visibility: self.visibility,
@@ -239,7 +212,7 @@ impl Lower for data::FunctionData {
 }
 
 /// Data about a function call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct FunctionRefData {
     pub span: SpanData,
     pub scope: DefId,
@@ -251,13 +224,13 @@ impl Lower for data::FunctionRefData {
 
     fn lower(self, tcx: TyCtxt) -> FunctionRefData {
         FunctionRefData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
         }
     }
 }
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ImplData {
     pub id: DefId,
     pub span: SpanData,
@@ -272,7 +245,7 @@ impl Lower for data::ImplData {
     fn lower(self, tcx: TyCtxt) -> ImplData {
         ImplData {
             id: make_def_id(self.id, &tcx.hir),
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             trait_ref: self.trait_ref,
             self_ref: self.self_ref,
@@ -280,7 +253,7 @@ impl Lower for data::ImplData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct InheritanceData {
     pub span: SpanData,
     pub base_id: DefId,
@@ -292,7 +265,7 @@ impl Lower for data::InheritanceData {
 
     fn lower(self, tcx: TyCtxt) -> InheritanceData {
         InheritanceData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             base_id: self.base_id,
             deriv_id: make_def_id(self.deriv_id, &tcx.hir)
         }
@@ -300,7 +273,7 @@ impl Lower for data::InheritanceData {
 }
 
 /// Data about a macro declaration.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MacroData {
     pub span: SpanData,
     pub name: String,
@@ -313,7 +286,7 @@ impl Lower for data::MacroData {
 
     fn lower(self, tcx: TyCtxt) -> MacroData {
         MacroData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             qualname: self.qualname,
             docs: self.docs,
@@ -322,7 +295,7 @@ impl Lower for data::MacroData {
 }
 
 /// Data about a macro use.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MacroUseData {
     pub span: SpanData,
     pub name: String,
@@ -338,17 +311,17 @@ impl Lower for data::MacroUseData {
 
     fn lower(self, tcx: TyCtxt) -> MacroUseData {
         MacroUseData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             qualname: self.qualname,
-            callee_span: SpanData::from_span(self.callee_span, tcx.sess.codemap()),
+            callee_span: span_from_span(self.callee_span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
         }
     }
 }
 
 /// Data about a method call.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct MethodCallData {
     pub span: SpanData,
     pub scope: DefId,
@@ -361,7 +334,7 @@ impl Lower for data::MethodCallData {
 
     fn lower(self, tcx: TyCtxt) -> MethodCallData {
         MethodCallData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
             decl_id: self.decl_id,
@@ -370,7 +343,7 @@ impl Lower for data::MethodCallData {
 }
 
 /// Data for method declarations (methods with a body are treated as functions).
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct MethodData {
     pub id: DefId,
     pub name: String,
@@ -391,7 +364,7 @@ impl Lower for data::MethodData {
 
     fn lower(self, tcx: TyCtxt) -> MethodData {
         MethodData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             scope: make_def_id(self.scope, &tcx.hir),
             id: make_def_id(self.id, &tcx.hir),
@@ -408,7 +381,7 @@ impl Lower for data::MethodData {
 }
 
 /// Data for modules.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ModData {
     pub id: DefId,
     pub name: String,
@@ -431,7 +404,7 @@ impl Lower for data::ModData {
             id: make_def_id(self.id, &tcx.hir),
             name: self.name,
             qualname: self.qualname,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             filename: self.filename,
             items: self.items.into_iter().map(|id| make_def_id(id, &tcx.hir)).collect(),
@@ -444,7 +417,7 @@ impl Lower for data::ModData {
 }
 
 /// Data for a reference to a module.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct ModRefData {
     pub span: SpanData,
     pub scope: DefId,
@@ -457,7 +430,7 @@ impl Lower for data::ModRefData {
 
     fn lower(self, tcx: TyCtxt) -> ModRefData {
         ModRefData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
             qualname: self.qualname,
@@ -465,7 +438,7 @@ impl Lower for data::ModRefData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct StructData {
     pub span: SpanData,
     pub name: String,
@@ -486,7 +459,7 @@ impl Lower for data::StructData {
 
     fn lower(self, tcx: TyCtxt) -> StructData {
         StructData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             id: make_def_id(self.id, &tcx.hir),
             ctor_id: make_def_id(self.ctor_id, &tcx.hir),
@@ -502,7 +475,7 @@ impl Lower for data::StructData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct StructVariantData {
     pub span: SpanData,
     pub name: String,
@@ -522,7 +495,7 @@ impl Lower for data::StructVariantData {
 
     fn lower(self, tcx: TyCtxt) -> StructVariantData {
         StructVariantData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             id: make_def_id(self.id, &tcx.hir),
             qualname: self.qualname,
@@ -537,7 +510,7 @@ impl Lower for data::StructVariantData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TraitData {
     pub span: SpanData,
     pub name: String,
@@ -557,7 +530,7 @@ impl Lower for data::TraitData {
 
     fn lower(self, tcx: TyCtxt) -> TraitData {
         TraitData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             id: make_def_id(self.id, &tcx.hir),
             qualname: self.qualname,
@@ -572,7 +545,7 @@ impl Lower for data::TraitData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TupleVariantData {
     pub span: SpanData,
     pub id: DefId,
@@ -592,7 +565,7 @@ impl Lower for data::TupleVariantData {
 
     fn lower(self, tcx: TyCtxt) -> TupleVariantData {
         TupleVariantData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             id: make_def_id(self.id, &tcx.hir),
             name: self.name,
             qualname: self.qualname,
@@ -608,7 +581,7 @@ impl Lower for data::TupleVariantData {
 }
 
 /// Data for a typedef.
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct TypeDefData {
     pub id: DefId,
     pub name: String,
@@ -629,7 +602,7 @@ impl Lower for data::TypeDefData {
         TypeDefData {
             id: make_def_id(self.id, &tcx.hir),
             name: self.name,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             qualname: self.qualname,
             value: self.value,
             visibility: self.visibility,
@@ -642,7 +615,7 @@ impl Lower for data::TypeDefData {
 }
 
 /// Data for a reference to a type or trait.
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct TypeRefData {
     pub span: SpanData,
     pub scope: DefId,
@@ -655,7 +628,7 @@ impl Lower for data::TypeRefData {
 
     fn lower(self, tcx: TyCtxt) -> TypeRefData {
         TypeRefData {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
             qualname: self.qualname,
@@ -663,7 +636,7 @@ impl Lower for data::TypeRefData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct UseData {
     pub id: DefId,
     pub span: SpanData,
@@ -679,7 +652,7 @@ impl Lower for data::UseData {
     fn lower(self, tcx: TyCtxt) -> UseData {
         UseData {
             id: make_def_id(self.id, &tcx.hir),
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             name: self.name,
             mod_id: self.mod_id,
             scope: make_def_id(self.scope, &tcx.hir),
@@ -688,7 +661,7 @@ impl Lower for data::UseData {
     }
 }
 
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct UseGlobData {
     pub id: DefId,
     pub span: SpanData,
@@ -703,7 +676,7 @@ impl Lower for data::UseGlobData {
     fn lower(self, tcx: TyCtxt) -> UseGlobData {
         UseGlobData {
             id: make_def_id(self.id, &tcx.hir),
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             names: self.names,
             scope: make_def_id(self.scope, &tcx.hir),
             visibility: self.visibility,
@@ -712,7 +685,7 @@ impl Lower for data::UseGlobData {
 }
 
 /// Data for local and global variables (consts and statics).
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct VariableData {
     pub id: DefId,
     pub name: String,
@@ -738,7 +711,7 @@ impl Lower for data::VariableData {
             kind: self.kind,
             name: self.name,
             qualname: self.qualname,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             value: self.value,
             type_value: self.type_value,
@@ -753,7 +726,7 @@ impl Lower for data::VariableData {
 
 /// Data for the use of some item (e.g., the use of a local variable, which
 /// will refer to that variables declaration (by ref_id)).
-#[derive(Debug, RustcEncodable)]
+#[derive(Debug)]
 pub struct VariableRefData {
     pub name: String,
     pub span: SpanData,
@@ -767,14 +740,14 @@ impl Lower for data::VariableRefData {
     fn lower(self, tcx: TyCtxt) -> VariableRefData {
         VariableRefData {
             name: self.name,
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             scope: make_def_id(self.scope, &tcx.hir),
             ref_id: self.ref_id,
         }
     }
 }
 
-#[derive(Clone, Debug, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct Signature {
     pub span: SpanData,
     pub text: String,
@@ -791,7 +764,7 @@ impl Lower for data::Signature {
 
     fn lower(self, tcx: TyCtxt) -> Signature {
         Signature {
-            span: SpanData::from_span(self.span, tcx.sess.codemap()),
+            span: span_from_span(self.span, tcx.sess.codemap()),
             text: self.text,
             ident_start: self.ident_start,
             ident_end: self.ident_end,
diff --git a/src/librustc_save_analysis/json_api_dumper.rs b/src/librustc_save_analysis/json_api_dumper.rs
index 277535f9e6513..41221ad986379 100644
--- a/src/librustc_save_analysis/json_api_dumper.rs
+++ b/src/librustc_save_analysis/json_api_dumper.rs
@@ -10,13 +10,14 @@
 
 use std::io::Write;
 
-use rustc::hir::def_id::DefId;
 use rustc_serialize::json::as_json;
 
 use external_data::*;
-use data::{VariableKind, Visibility, SigElement};
+use data::{VariableKind, Visibility};
 use dump::Dump;
-use super::Format;
+use json_dumper::id_from_def_id;
+
+use rls_data::{Analysis, Import, ImportKind, Def, DefKind, CratePreludeData};
 
 
 // A dumper to dump a restricted set of JSON information, designed for use with
@@ -24,8 +25,7 @@ use super::Format;
 // information here, and (for example) generate Rustdoc URLs, but don't need
 // information for navigating the source of the crate.
 // Relative to the regular JSON save-analysis info, this form is filtered to
-// remove non-visible items, but includes some extra info for items (e.g., the
-// parent field for finding the struct to which a field belongs).
+// remove non-visible items.
 pub struct JsonApiDumper<'b, W: Write + 'b> {
     output: &'b mut W,
     result: Analysis,
@@ -48,7 +48,7 @@ impl<'b, W: Write> Drop for JsonApiDumper<'b, W> {
 macro_rules! impl_fn {
     ($fn_name: ident, $data_type: ident, $bucket: ident) => {
         fn $fn_name(&mut self, data: $data_type) {
-            if let Some(datum) = From::from(data) {
+            if let Some(datum) = data.into() {
                 self.result.$bucket.push(datum);
             }
         }
@@ -77,11 +77,11 @@ impl<'b, W: Write + 'b> Dump for JsonApiDumper<'b, W> {
 
     fn impl_data(&mut self, data: ImplData) {
         if data.self_ref.is_some() {
-            self.result.relations.push(From::from(data));
+            self.result.relations.push(data.into());
         }
     }
     fn inheritance(&mut self, data: InheritanceData) {
-        self.result.relations.push(From::from(data));
+        self.result.relations.push(data.into());
     }
 }
 
@@ -90,426 +90,261 @@ impl<'b, W: Write + 'b> Dump for JsonApiDumper<'b, W> {
 // method, but not the supplied method). In both cases, we are currently
 // ignoring it.
 
-#[derive(Debug, RustcEncodable)]
-struct Analysis {
-    kind: Format,
-    prelude: Option<CratePreludeData>,
-    imports: Vec<Import>,
-    defs: Vec<Def>,
-    relations: Vec<Relation>,
-    // These two fields are dummies so that clients can parse the two kinds of
-    // JSON data in the same way.
-    refs: Vec<()>,
-    macro_refs: Vec<()>,
-}
-
-impl Analysis {
-    fn new() -> Analysis {
-        Analysis {
-            kind: Format::JsonApi,
-            prelude: None,
-            imports: vec![],
-            defs: vec![],
-            relations: vec![],
-            refs: vec![],
-            macro_refs: vec![],
-        }
-    }
-}
-
-// DefId::index is a newtype and so the JSON serialisation is ugly. Therefore
-// we use our own Id which is the same, but without the newtype.
-#[derive(Debug, RustcEncodable)]
-struct Id {
-    krate: u32,
-    index: u32,
-}
-
-impl From<DefId> for Id {
-    fn from(id: DefId) -> Id {
-        Id {
-            krate: id.krate.as_u32(),
-            index: id.index.as_u32(),
-        }
-    }
-}
-
-#[derive(Debug, RustcEncodable)]
-struct Import {
-    kind: ImportKind,
-    id: Id,
-    span: SpanData,
-    name: String,
-    value: String,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum ImportKind {
-    Use,
-    GlobUse,
-}
-
-impl From<UseData> for Option<Import> {
-    fn from(data: UseData) -> Option<Import> {
-        match data.visibility {
+impl Into<Option<Import>> for UseData {
+    fn into(self) -> Option<Import> {
+        match self.visibility {
             Visibility::Public => Some(Import {
                 kind: ImportKind::Use,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
+                ref_id: self.mod_id.map(|id| id_from_def_id(id)),
+                span: self.span,
+                name: self.name,
                 value: String::new(),
             }),
             _ => None,
         }
     }
 }
-impl From<UseGlobData> for Option<Import> {
-    fn from(data: UseGlobData) -> Option<Import> {
-        match data.visibility {
+impl Into<Option<Import>> for UseGlobData {
+    fn into(self) -> Option<Import> {
+        match self.visibility {
             Visibility::Public => Some(Import {
                 kind: ImportKind::GlobUse,
-                id: From::from(data.id),
-                span: data.span,
+                ref_id: None,
+                span: self.span,
                 name: "*".to_owned(),
-                value: data.names.join(", "),
+                value: self.names.join(", "),
             }),
             _ => None,
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-struct Def {
-    kind: DefKind,
-    id: Id,
-    span: SpanData,
-    name: String,
-    qualname: String,
-    value: String,
-    parent: Option<Id>,
-    children: Vec<Id>,
-    decl_id: Option<Id>,
-    docs: String,
-    sig: Option<JsonSignature>,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum DefKind {
-    // value = variant names
-    Enum,
-    // value = enum name + variant name + types
-    Tuple,
-    // value = [enum name +] name + fields
-    Struct,
-    // value = signature
-    Trait,
-    // value = type + generics
-    Function,
-    // value = type + generics
-    Method,
-    // No id, no value.
-    Macro,
-    // value = file_name
-    Mod,
-    // value = aliased type
-    Type,
-    // value = type and init expression (for all variable kinds).
-    Static,
-    Const,
-    Field,
-}
-
-impl From<EnumData> for Option<Def> {
-    fn from(data: EnumData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for EnumData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Enum,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
                 parent: None,
-                children: data.variants.into_iter().map(|id| From::from(id)).collect(),
+                children: self.variants.into_iter().map(|id| id_from_def_id(id)).collect(),
                 decl_id: None,
-                docs: data.docs,
-                sig: Some(From::from(data.sig)),
+                docs: self.docs,
+                sig: Some(self.sig.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
 
-impl From<TupleVariantData> for Option<Def> {
-    fn from(data: TupleVariantData) -> Option<Def> {
+impl Into<Option<Def>> for TupleVariantData {
+    fn into(self) -> Option<Def> {
         Some(Def {
             kind: DefKind::Tuple,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
-            parent: data.parent.map(|id| From::from(id)),
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: self.parent.map(|id| id_from_def_id(id)),
             children: vec![],
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: vec![],
         })
     }
 }
-impl From<StructVariantData> for Option<Def> {
-    fn from(data: StructVariantData) -> Option<Def> {
+impl Into<Option<Def>> for StructVariantData {
+    fn into(self) -> Option<Def> {
         Some(Def {
             kind: DefKind::Struct,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
-            parent: data.parent.map(|id| From::from(id)),
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: self.parent.map(|id| id_from_def_id(id)),
             children: vec![],
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: vec![],
         })
     }
 }
-impl From<StructData> for Option<Def> {
-    fn from(data: StructData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for StructData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
             kind: DefKind::Struct,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
             parent: None,
-            children: data.fields.into_iter().map(|id| From::from(id)).collect(),
+            children: self.fields.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: vec![],
         }),
             _ => None,
         }
     }
 }
-impl From<TraitData> for Option<Def> {
-    fn from(data: TraitData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for TraitData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Trait,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
-                children: data.items.into_iter().map(|id| From::from(id)).collect(),
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
+                children: self.items.into_iter().map(|id| id_from_def_id(id)).collect(),
                 parent: None,
                 decl_id: None,
-                docs: data.docs,
-                sig: Some(From::from(data.sig)),
+                docs: self.docs,
+                sig: Some(self.sig.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
-impl From<FunctionData> for Option<Def> {
-    fn from(data: FunctionData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for FunctionData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Function,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
                 children: vec![],
-                parent: data.parent.map(|id| From::from(id)),
+                parent: self.parent.map(|id| id_from_def_id(id)),
                 decl_id: None,
-                docs: data.docs,
-                sig: Some(From::from(data.sig)),
+                docs: self.docs,
+                sig: Some(self.sig.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
-impl From<MethodData> for Option<Def> {
-    fn from(data: MethodData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for MethodData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Method,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
                 children: vec![],
-                parent: data.parent.map(|id| From::from(id)),
-                decl_id: data.decl_id.map(|id| From::from(id)),
-                docs: data.docs,
-                sig: Some(From::from(data.sig)),
+                parent: self.parent.map(|id| id_from_def_id(id)),
+                decl_id: self.decl_id.map(|id| id_from_def_id(id)),
+                docs: self.docs,
+                sig: Some(self.sig.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
-impl From<MacroData> for Option<Def> {
-    fn from(data: MacroData) -> Option<Def> {
+impl Into<Option<Def>> for MacroData {
+    fn into(self) -> Option<Def> {
         Some(Def {
             kind: DefKind::Macro,
-            id: From::from(null_def_id()),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
+            id: id_from_def_id(null_def_id()),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
             value: String::new(),
             children: vec![],
             parent: None,
             decl_id: None,
-            docs: data.docs,
+            docs: self.docs,
             sig: None,
+            attributes: vec![],
         })
     }
 }
-impl From<ModData> for Option<Def> {
-    fn from(data:ModData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for ModData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Mod,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.filename,
-                children: data.items.into_iter().map(|id| From::from(id)).collect(),
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.filename,
+                children: self.items.into_iter().map(|id| id_from_def_id(id)).collect(),
                 parent: None,
                 decl_id: None,
-                docs: data.docs,
-                sig: Some(From::from(data.sig)),
+                docs: self.docs,
+                sig: Some(self.sig.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
-impl From<TypeDefData> for Option<Def> {
-    fn from(data: TypeDefData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for TypeDefData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
                 kind: DefKind::Type,
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
                 children: vec![],
-                parent: data.parent.map(|id| From::from(id)),
+                parent: self.parent.map(|id| id_from_def_id(id)),
                 decl_id: None,
                 docs: String::new(),
-                sig: data.sig.map(|s| From::from(s)),
+                sig: self.sig.map(|s| s.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
 
-impl From<VariableData> for Option<Def> {
-    fn from(data: VariableData) -> Option<Def> {
-        match data.visibility {
+impl Into<Option<Def>> for VariableData {
+    fn into(self) -> Option<Def> {
+        match self.visibility {
             Visibility::Public => Some(Def {
-                kind: match data.kind {
+                kind: match self.kind {
                     VariableKind::Static => DefKind::Static,
                     VariableKind::Const => DefKind::Const,
                     VariableKind::Local => { return None }
                     VariableKind::Field => DefKind::Field,
                 },
-                id: From::from(data.id),
-                span: data.span,
-                name: data.name,
-                qualname: data.qualname,
-                value: data.value,
+                id: id_from_def_id(self.id),
+                span: self.span,
+                name: self.name,
+                qualname: self.qualname,
+                value: self.value,
                 children: vec![],
-                parent: data.parent.map(|id| From::from(id)),
+                parent: self.parent.map(|id| id_from_def_id(id)),
                 decl_id: None,
-                docs: data.docs,
-                sig: data.sig.map(|s| From::from(s)),
+                docs: self.docs,
+                sig: self.sig.map(|s| s.into()),
+                attributes: vec![],
             }),
             _ => None,
         }
     }
 }
-
-#[derive(Debug, RustcEncodable)]
-struct Relation {
-    span: SpanData,
-    kind: RelationKind,
-    from: Id,
-    to: Id,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum RelationKind {
-    Impl,
-    SuperTrait,
-}
-
-impl From<ImplData> for Relation {
-    fn from(data: ImplData) -> Relation {
-        Relation {
-            span: data.span,
-            kind: RelationKind::Impl,
-            from: From::from(data.self_ref.unwrap_or(null_def_id())),
-            to: From::from(data.trait_ref.unwrap_or(null_def_id())),
-        }
-    }
-}
-
-impl From<InheritanceData> for Relation {
-    fn from(data: InheritanceData) -> Relation {
-        Relation {
-            span: data.span,
-            kind: RelationKind::SuperTrait,
-            from: From::from(data.base_id),
-            to: From::from(data.deriv_id),
-        }
-    }
-}
-
-#[derive(Debug, RustcEncodable)]
-pub struct JsonSignature {
-    span: SpanData,
-    text: String,
-    ident_start: usize,
-    ident_end: usize,
-    defs: Vec<JsonSigElement>,
-    refs: Vec<JsonSigElement>,
-}
-
-impl From<Signature> for JsonSignature {
-    fn from(data: Signature) -> JsonSignature {
-        JsonSignature {
-            span: data.span,
-            text: data.text,
-            ident_start: data.ident_start,
-            ident_end: data.ident_end,
-            defs: data.defs.into_iter().map(|s| From::from(s)).collect(),
-            refs: data.refs.into_iter().map(|s| From::from(s)).collect(),
-        }
-    }
-}
-
-#[derive(Debug, RustcEncodable)]
-pub struct JsonSigElement {
-    id: Id,
-    start: usize,
-    end: usize,
-}
-
-impl From<SigElement> for JsonSigElement {
-    fn from(data: SigElement) -> JsonSigElement {
-        JsonSigElement {
-            id: From::from(data.id),
-            start: data.start,
-            end: data.end,
-        }
-    }
-}
diff --git a/src/librustc_save_analysis/json_dumper.rs b/src/librustc_save_analysis/json_dumper.rs
index 1b72489f83c67..acc877d394775 100644
--- a/src/librustc_save_analysis/json_dumper.rs
+++ b/src/librustc_save_analysis/json_dumper.rs
@@ -13,10 +13,14 @@ use std::io::Write;
 use rustc::hir::def_id::DefId;
 use rustc_serialize::json::as_json;
 
+use rls_data::{self, Id, Analysis, Import, ImportKind, Def, DefKind, Ref, RefKind, MacroRef,
+               Relation, RelationKind, Signature, SigElement, CratePreludeData};
+use rls_span::{Column, Row};
+
+use external_data;
 use external_data::*;
-use data::{VariableKind, SigElement};
+use data::{self, VariableKind};
 use dump::Dump;
-use super::Format;
 
 pub struct JsonDumper<'b, W: Write + 'b> {
     output: &'b mut W,
@@ -40,7 +44,7 @@ impl<'b, W: Write> Drop for JsonDumper<'b, W> {
 macro_rules! impl_fn {
     ($fn_name: ident, $data_type: ident, $bucket: ident) => {
         fn $fn_name(&mut self, data: $data_type) {
-            self.result.$bucket.push(From::from(data));
+            self.result.$bucket.push(data.into());
         }
     }
 }
@@ -75,21 +79,22 @@ impl<'b, W: Write + 'b> Dump for JsonDumper<'b, W> {
     impl_fn!(macro_use, MacroUseData, macro_refs);
 
     fn mod_data(&mut self, data: ModData) {
-        let id: Id = From::from(data.id);
+        let id: Id = id_from_def_id(data.id);
         let mut def = Def {
             kind: DefKind::Mod,
             id: id,
-            span: data.span,
+            span: data.span.into(),
             name: data.name,
             qualname: data.qualname,
             value: data.filename,
-            children: data.items.into_iter().map(|id| From::from(id)).collect(),
+            parent: None,
+            children: data.items.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
             docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            sig: Some(data.sig.into()),
+            attributes: data.attributes.into_iter().map(|a| a.into()).collect(),
         };
-        if def.span.file_name != def.value {
+        if def.span.file_name.to_str().unwrap() != def.value {
             // If the module is an out-of-line defintion, then we'll make the
             // defintion the first character in the module's file and turn the
             // the declaration into a reference to it.
@@ -99,14 +104,14 @@ impl<'b, W: Write + 'b> Dump for JsonDumper<'b, W> {
                 ref_id: id,
             };
             self.result.refs.push(rf);
-            def.span = SpanData {
-                file_name: def.value.clone(),
+            def.span = rls_data::SpanData {
+                file_name: def.value.clone().into(),
                 byte_start: 0,
                 byte_end: 0,
-                line_start: 1,
-                line_end: 1,
-                column_start: 1,
-                column_end: 1,
+                line_start: Row::new_one_indexed(1),
+                line_end: Row::new_one_indexed(1),
+                column_start: Column::new_one_indexed(1),
+                column_end: Column::new_one_indexed(1),
             }
         }
 
@@ -115,11 +120,11 @@ impl<'b, W: Write + 'b> Dump for JsonDumper<'b, W> {
 
     fn impl_data(&mut self, data: ImplData) {
         if data.self_ref.is_some() {
-            self.result.relations.push(From::from(data));
+            self.result.relations.push(data.into());
         }
     }
     fn inheritance(&mut self, data: InheritanceData) {
-        self.result.relations.push(From::from(data));
+        self.result.relations.push(data.into());
     }
 }
 
@@ -129,476 +134,342 @@ impl<'b, W: Write + 'b> Dump for JsonDumper<'b, W> {
 // method, but not the supplied method). In both cases, we are currently
 // ignoring it.
 
-#[derive(Debug, RustcEncodable)]
-struct Analysis {
-    kind: Format,
-    prelude: Option<CratePreludeData>,
-    imports: Vec<Import>,
-    defs: Vec<Def>,
-    refs: Vec<Ref>,
-    macro_refs: Vec<MacroRef>,
-    relations: Vec<Relation>,
-}
-
-impl Analysis {
-    fn new() -> Analysis {
-        Analysis {
-            kind: Format::Json,
-            prelude: None,
-            imports: vec![],
-            defs: vec![],
-            refs: vec![],
-            macro_refs: vec![],
-            relations: vec![],
-        }
-    }
-}
-
 // DefId::index is a newtype and so the JSON serialisation is ugly. Therefore
 // we use our own Id which is the same, but without the newtype.
-#[derive(Clone, Copy, Debug, RustcEncodable)]
-struct Id {
-    krate: u32,
-    index: u32,
-}
-
-impl From<DefId> for Id {
-    fn from(id: DefId) -> Id {
-        Id {
-            krate: id.krate.as_u32(),
-            index: id.index.as_u32(),
-        }
+pub fn id_from_def_id(id: DefId) -> Id {
+    Id {
+        krate: id.krate.as_u32(),
+        index: id.index.as_u32(),
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-struct Import {
-    kind: ImportKind,
-    ref_id: Option<Id>,
-    span: SpanData,
-    name: String,
-    value: String,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum ImportKind {
-    ExternCrate,
-    Use,
-    GlobUse,
-}
-
-impl From<ExternCrateData> for Import {
-    fn from(data: ExternCrateData) -> Import {
+impl Into<Import> for ExternCrateData {
+    fn into(self) -> Import {
         Import {
             kind: ImportKind::ExternCrate,
             ref_id: None,
-            span: data.span,
-            name: data.name,
+            span: self.span,
+            name: self.name,
             value: String::new(),
         }
     }
 }
-impl From<UseData> for Import {
-    fn from(data: UseData) -> Import {
+impl Into<Import> for UseData {
+    fn into(self) -> Import {
         Import {
             kind: ImportKind::Use,
-            ref_id: data.mod_id.map(|id| From::from(id)),
-            span: data.span,
-            name: data.name,
+            ref_id: self.mod_id.map(|id| id_from_def_id(id)),
+            span: self.span,
+            name: self.name,
             value: String::new(),
         }
     }
 }
-impl From<UseGlobData> for Import {
-    fn from(data: UseGlobData) -> Import {
+impl Into<Import> for UseGlobData {
+    fn into(self) -> Import {
         Import {
             kind: ImportKind::GlobUse,
             ref_id: None,
-            span: data.span,
+            span: self.span,
             name: "*".to_owned(),
-            value: data.names.join(", "),
+            value: self.names.join(", "),
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-struct Def {
-    kind: DefKind,
-    id: Id,
-    span: SpanData,
-    name: String,
-    qualname: String,
-    value: String,
-    children: Vec<Id>,
-    decl_id: Option<Id>,
-    docs: String,
-    sig: Option<JsonSignature>,
-    attributes: Vec<Attribute>,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum DefKind {
-    // value = variant names
-    Enum,
-    // value = enum name + variant name + types
-    Tuple,
-    // value = [enum name +] name + fields
-    Struct,
-    // value = signature
-    Trait,
-    // value = type + generics
-    Function,
-    // value = type + generics
-    Method,
-    // No id, no value.
-    Macro,
-    // value = file_name
-    Mod,
-    // value = aliased type
-    Type,
-    // value = type and init expression (for all variable kinds).
-    Local,
-    Static,
-    Const,
-    Field,
-}
-
-impl From<EnumData> for Def {
-    fn from(data: EnumData) -> Def {
+impl Into<Def> for EnumData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Enum,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
-            children: data.variants.into_iter().map(|id| From::from(id)).collect(),
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
+            children: self.variants.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
 
-impl From<TupleVariantData> for Def {
-    fn from(data: TupleVariantData) -> Def {
+impl Into<Def> for TupleVariantData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Tuple,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
             children: vec![],
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<StructVariantData> for Def {
-    fn from(data: StructVariantData) -> Def {
+impl Into<Def> for StructVariantData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Struct,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
             children: vec![],
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<StructData> for Def {
-    fn from(data: StructData) -> Def {
+impl Into<Def> for StructData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Struct,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
-            children: data.fields.into_iter().map(|id| From::from(id)).collect(),
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
+            children: self.fields.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<TraitData> for Def {
-    fn from(data: TraitData) -> Def {
+impl Into<Def> for TraitData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Trait,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
-            children: data.items.into_iter().map(|id| From::from(id)).collect(),
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
+            children: self.items.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<FunctionData> for Def {
-    fn from(data: FunctionData) -> Def {
+impl Into<Def> for FunctionData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Function,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
             children: vec![],
             decl_id: None,
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<MethodData> for Def {
-    fn from(data: MethodData) -> Def {
+impl Into<Def> for MethodData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Method,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
             children: vec![],
-            decl_id: data.decl_id.map(|id| From::from(id)),
-            docs: data.docs,
-            sig: Some(From::from(data.sig)),
-            attributes: data.attributes,
+            decl_id: self.decl_id.map(|id| id_from_def_id(id)),
+            docs: self.docs,
+            sig: Some(self.sig.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<MacroData> for Def {
-    fn from(data: MacroData) -> Def {
+impl Into<Def> for MacroData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Macro,
-            id: From::from(null_def_id()),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
+            id: id_from_def_id(null_def_id()),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
             value: String::new(),
+            parent: None,
             children: vec![],
             decl_id: None,
-            docs: data.docs,
+            docs: self.docs,
             sig: None,
             attributes: vec![],
         }
     }
 }
-impl From<TypeDefData> for Def {
-    fn from(data: TypeDefData) -> Def {
+impl Into<Def> for TypeDefData {
+    fn into(self) -> Def {
         Def {
             kind: DefKind::Type,
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.value,
+            parent: None,
             children: vec![],
             decl_id: None,
             docs: String::new(),
-            sig: data.sig.map(|s| From::from(s)),
-            attributes: data.attributes,
+            sig: self.sig.map(|s| s.into()),
+            attributes: self.attributes,
         }
     }
 }
-impl From<VariableData> for Def {
-    fn from(data: VariableData) -> Def {
+impl Into<Def> for VariableData {
+    fn into(self) -> Def {
         Def {
-            kind: match data.kind {
+            kind: match self.kind {
                 VariableKind::Static => DefKind::Static,
                 VariableKind::Const => DefKind::Const,
                 VariableKind::Local => DefKind::Local,
                 VariableKind::Field => DefKind::Field,
             },
-            id: From::from(data.id),
-            span: data.span,
-            name: data.name,
-            qualname: data.qualname,
-            value: data.type_value,
+            id: id_from_def_id(self.id),
+            span: self.span,
+            name: self.name,
+            qualname: self.qualname,
+            value: self.type_value,
+            parent: None,
             children: vec![],
             decl_id: None,
-            docs: data.docs,
+            docs: self.docs,
             sig: None,
-            attributes: data.attributes,
+            attributes: self.attributes,
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-enum RefKind {
-    Function,
-    Mod,
-    Type,
-    Variable,
-}
-
-#[derive(Debug, RustcEncodable)]
-struct Ref {
-    kind: RefKind,
-    span: SpanData,
-    ref_id: Id,
-}
-
-impl From<FunctionRefData> for Ref {
-    fn from(data: FunctionRefData) -> Ref {
+impl Into<Ref> for FunctionRefData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Function,
-            span: data.span,
-            ref_id: From::from(data.ref_id),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id),
         }
     }
 }
-impl From<FunctionCallData> for Ref {
-    fn from(data: FunctionCallData) -> Ref {
+impl Into<Ref> for FunctionCallData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Function,
-            span: data.span,
-            ref_id: From::from(data.ref_id),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id),
         }
     }
 }
-impl From<MethodCallData> for Ref {
-    fn from(data: MethodCallData) -> Ref {
+impl Into<Ref> for MethodCallData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Function,
-            span: data.span,
-            ref_id: From::from(data.ref_id.or(data.decl_id).unwrap_or(null_def_id())),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id.or(self.decl_id).unwrap_or(null_def_id())),
         }
     }
 }
-impl From<ModRefData> for Ref {
-    fn from(data: ModRefData) -> Ref {
+impl Into<Ref> for ModRefData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Mod,
-            span: data.span,
-            ref_id: From::from(data.ref_id.unwrap_or(null_def_id())),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id.unwrap_or(null_def_id())),
         }
     }
 }
-impl From<TypeRefData> for Ref {
-    fn from(data: TypeRefData) -> Ref {
+impl Into<Ref> for TypeRefData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Type,
-            span: data.span,
-            ref_id: From::from(data.ref_id.unwrap_or(null_def_id())),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id.unwrap_or(null_def_id())),
         }
     }
 }
-impl From<VariableRefData> for Ref {
-    fn from(data: VariableRefData) -> Ref {
+impl Into<Ref> for VariableRefData {
+    fn into(self) -> Ref {
         Ref {
             kind: RefKind::Variable,
-            span: data.span,
-            ref_id: From::from(data.ref_id),
+            span: self.span,
+            ref_id: id_from_def_id(self.ref_id),
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-struct MacroRef {
-    span: SpanData,
-    qualname: String,
-    callee_span: SpanData,
-}
-
-impl From<MacroUseData> for MacroRef {
-    fn from(data: MacroUseData) -> MacroRef {
+impl Into<MacroRef> for MacroUseData {
+    fn into(self) -> MacroRef {
         MacroRef {
-            span: data.span,
-            qualname: data.qualname,
-            callee_span: data.callee_span,
+            span: self.span,
+            qualname: self.qualname,
+            callee_span: self.callee_span.into(),
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-struct Relation {
-    span: SpanData,
-    kind: RelationKind,
-    from: Id,
-    to: Id,
-}
-
-#[derive(Debug, RustcEncodable)]
-enum RelationKind {
-    Impl,
-    SuperTrait,
-}
-
-impl From<ImplData> for Relation {
-    fn from(data: ImplData) -> Relation {
+impl Into<Relation> for ImplData {
+    fn into(self) -> Relation {
         Relation {
-            span: data.span,
+            span: self.span,
             kind: RelationKind::Impl,
-            from: From::from(data.self_ref.unwrap_or(null_def_id())),
-            to: From::from(data.trait_ref.unwrap_or(null_def_id())),
+            from: id_from_def_id(self.self_ref.unwrap_or(null_def_id())),
+            to: id_from_def_id(self.trait_ref.unwrap_or(null_def_id())),
         }
     }
 }
 
-impl From<InheritanceData> for Relation {
-    fn from(data: InheritanceData) -> Relation {
+impl Into<Relation> for InheritanceData {
+    fn into(self) -> Relation {
         Relation {
-            span: data.span,
+            span: self.span,
             kind: RelationKind::SuperTrait,
-            from: From::from(data.base_id),
-            to: From::from(data.deriv_id),
+            from: id_from_def_id(self.base_id),
+            to: id_from_def_id(self.deriv_id),
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-pub struct JsonSignature {
-    span: SpanData,
-    text: String,
-    ident_start: usize,
-    ident_end: usize,
-    defs: Vec<JsonSigElement>,
-    refs: Vec<JsonSigElement>,
-}
-
-impl From<Signature> for JsonSignature {
-    fn from(data: Signature) -> JsonSignature {
-        JsonSignature {
-            span: data.span,
-            text: data.text,
-            ident_start: data.ident_start,
-            ident_end: data.ident_end,
-            defs: data.defs.into_iter().map(|s| From::from(s)).collect(),
-            refs: data.refs.into_iter().map(|s| From::from(s)).collect(),
+impl Into<Signature> for external_data::Signature {
+    fn into(self) -> Signature {
+        Signature {
+            span: self.span,
+            text: self.text,
+            ident_start: self.ident_start,
+            ident_end: self.ident_end,
+            defs: self.defs.into_iter().map(|s| s.into()).collect(),
+            refs: self.refs.into_iter().map(|s| s.into()).collect(),
         }
     }
 }
 
-#[derive(Debug, RustcEncodable)]
-pub struct JsonSigElement {
-    id: Id,
-    start: usize,
-    end: usize,
-}
-
-impl From<SigElement> for JsonSigElement {
-    fn from(data: SigElement) -> JsonSigElement {
-        JsonSigElement {
-            id: From::from(data.id),
-            start: data.start,
-            end: data.end,
+impl Into<SigElement> for data::SigElement {
+    fn into(self) -> SigElement {
+        SigElement {
+            id: id_from_def_id(self.id),
+            start: self.start,
+            end: self.end,
         }
     }
 }
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 581b23d52142d..5e2b1df9d34f8 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -26,9 +26,12 @@
 
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
-extern crate serialize as rustc_serialize;
+extern crate rustc_serialize;
 extern crate syntax_pos;
 
+extern crate rls_data;
+extern crate rls_span;
+
 
 mod csv_dumper;
 mod json_api_dumper;