125 files changed, 6348 insertions, 1996 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 5848e61c7..d909bc3d5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,14 +2,20 @@
 # It is not intended for manual editing.
 [[package]]
 name = "addr2line"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a49806b9dadc843c61e7c97e72490ad7f7220ae249012fbda9ad0609457c0543"
+checksum = "602d785912f476e480434627e8732e6766b760c045bbf897d9dfaa9f4fbd399c"
 dependencies = [
  "gimli",
 ]
 
 [[package]]
+name = "adler32"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "567b077b825e468cc974f0020d4082ee6e03132512f207ef1a02fd5d00d1f32d"
+
+[[package]]
 name = "aho-corasick"
 version = "0.7.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -55,22 +61,23 @@ checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 
 [[package]]
 name = "backtrace"
-version = "0.3.48"
+version = "0.3.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0df2f85c8a2abbe3b7d7e748052fdd9b76a0458fdeb16ad4223f5eca78c7c130"
+checksum = "05100821de9e028f12ae3d189176b41ee198341eb8f369956407fea2f5cc666c"
 dependencies = [
  "addr2line",
  "cfg-if",
  "libc",
+ "miniz_oxide",
  "object",
  "rustc-demangle",
 ]
 
 [[package]]
 name = "base64"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53d1ccbaf7d9ec9537465a97bf19edc1a4e158ecb49fc16178202238c569cc42"
+checksum = "e223af0dc48c96d4f8342ec01a4974f139df863896b316681efd36742f22cc67"
 
 [[package]]
 name = "bitflags"
@@ -281,9 +288,9 @@ checksum = "69b26e475fd29098530e709294e94e661974c851aed42512793f120fed4e199f"
 
 [[package]]
 name = "dtoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4358a9e11b9a09cf52383b451b49a169e8d797b68aa02301ff586d70d9661ea3"
+checksum = "134951f4028bdadb9b84baf4232681efbf277da25144b9b0ad65df75946c422b"
 
 [[package]]
 name = "either"
@@ -438,9 +445,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.13"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91780f809e750b0a89f5544be56617ff6b1227ee485bcb06ebe10cdf89bd3b71"
+checksum = "b9586eedd4ce6b3c498bc3b4dd92fc9f11166aa908a914071953768066c67909"
 dependencies = [
  "libc",
 ]
@@ -528,9 +535,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "jemalloc-ctl"
@@ -633,9 +640,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-server"
-version = "0.3.2"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dccec31bfd027ac0dd288a78e19005fd89624d9099456e284b5241316a6c3072"
+checksum = "53b4ace8ebe5d2aff3687ce0ed507f6020d6a47a7de2b0d3d664ea237ffb0c62"
 dependencies = [
  "crossbeam-channel",
  "log",
@@ -695,6 +702,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "miniz_oxide"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "791daaae1ed6889560f8c4359194f56648355540573244a5448a83ba1ecc7435"
+dependencies = [
+ "adler32",
+]
+
+[[package]]
 name = "mio"
 version = "0.6.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -778,9 +794,9 @@ dependencies = [
 
 [[package]]
 name = "object"
-version = "0.19.0"
+version = "0.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9cbca9424c482ee628fa549d9c812e2cd22f1180b9222c9200fdfa6eb31aecb2"
+checksum = "1ab52be62400ca80aa00285d25253d7f7c437b7375c4de678f5405d3afe82ca5"
 
 [[package]]
 name = "once_cell"
@@ -814,9 +830,9 @@ dependencies = [
 
 [[package]]
 name = "paste"
-version = "0.1.16"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d508492eeb1e5c38ee696371bf7b9fc33c83d46a7d451606b96458fbbbdc2dec"
+checksum = "45ca20c77d80be666aef2b45486da86238fabe33e38306bd3118fe4af33fa880"
 dependencies = [
  "paste-impl",
  "proc-macro-hack",
@@ -824,14 +840,11 @@ dependencies = [
 
 [[package]]
 name = "paste-impl"
-version = "0.1.16"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "84f328a6a63192b333fce5fbb4be79db6758a4d518dfac6d54412f1492f72d32"
+checksum = "d95a7db200b97ef370c8e6de0088252f7e0dfff7d047a28528e47456c0fc98b6"
 dependencies = [
  "proc-macro-hack",
- "proc-macro2",
- "quote",
- "syn",
 ]
 
 [[package]]
@@ -856,9 +869,9 @@ dependencies = [
 
 [[package]]
 name = "pico-args"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ad1f1b834a05d42dae330066e9699a173b28185b3bdc3dbf14ca239585de8cc"
+checksum = "6a71836ceac43f0349e3bd964f5bb902f7b003916f32a4ad00354dafc447fa8f"
 
 [[package]]
 name = "plain"
@@ -1062,6 +1075,7 @@ dependencies = [
  "ra_hir",
  "ra_ide_db",
  "ra_prof",
+ "ra_ssr",
  "ra_syntax",
  "ra_text_edit",
  "rand",
@@ -1167,6 +1181,18 @@ dependencies = [
 ]
 
 [[package]]
+name = "ra_ssr"
+version = "0.1.0"
+dependencies = [
+ "ra_db",
+ "ra_hir",
+ "ra_ide_db",
+ "ra_syntax",
+ "ra_text_edit",
+ "rustc-hash",
+]
+
+[[package]]
 name = "ra_syntax"
 version = "0.1.0"
 dependencies = [
@@ -1275,10 +1301,11 @@ dependencies = [
 
 [[package]]
 name = "rayon"
-version = "1.3.0"
+version = "1.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db6ce3297f9c85e16621bb8cca38a06779ffc31bb8184e1be4bed2be4678a098"
+checksum = "62f02856753d04e03e26929f820d0a0a337ebe71f849801eea335d464b349080"
 dependencies = [
+ "autocfg",
  "crossbeam-deque",
  "either",
  "rayon-core",
@@ -1286,9 +1313,9 @@ dependencies = [
 
 [[package]]
 name = "rayon-core"
-version = "1.7.0"
+version = "1.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08a89b46efaf957e52b18062fb2f4660f8b8a4dde1807ca002690868ef2c85a9"
+checksum = "e92e15d89083484e11353891f1af602cc661426deb9564c298b270c726973280"
 dependencies = [
  "crossbeam-deque",
  "crossbeam-queue",
@@ -1323,15 +1350,15 @@ checksum = "26412eb97c6b088a6997e05f69403a802a92d520de2f8e63c2b65f9e0f47c4e8"
 
 [[package]]
 name = "relative-path"
-version = "1.0.0"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bedde000f40f2921ce439ea165c9c53fd629bfa115140c72e22aceacb4a21954"
+checksum = "c602122c47b382cd045b10866a084b184035d45d8c2609cdd3762852ddfae2a1"
 
 [[package]]
 name = "remove_dir_all"
-version = "0.5.2"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a83fa3702a688b9359eccba92d153ac33fd2e8462f9e0e3fdf155239ea7792e"
+checksum = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
 dependencies = [
  "winapi 0.3.8",
 ]
@@ -1505,18 +1532,18 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.111"
+version = "1.0.113"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9124df5b40cbd380080b2cc6ab894c040a3070d995f5c9dc77e18c34a8ae37d"
+checksum = "6135c78461981c79497158ef777264c51d9d0f4f3fc3a4d22b915900e42dac6a"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.111"
+version = "1.0.113"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f2c3ac8e6ca1e9c80b8be1023940162bf81ae3cffbb1809474152f2ce1eb250"
+checksum = "93c5eaa17d0954cb481cdcfffe9d84fcfa7a1a9f2349271e678677be4c26ae31"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1536,9 +1563,9 @@ dependencies = [
 
 [[package]]
 name = "serde_repr"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd02c7587ec314570041b2754829f84d873ced14a96d1fd1823531e11db40573"
+checksum = "2dc6b7951b17b051f3210b063f12cc17320e2fe30ae05b0fe2a3abb068551c76"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1590,9 +1617,9 @@ checksum = "ab16ced94dbd8a46c82fd81e3ed9a8727dac2977ea869d217bcc4ea1f122e81f"
 
 [[package]]
 name = "syn"
-version = "1.0.31"
+version = "1.0.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5304cfdf27365b7585c25d4af91b35016ed21ef88f17ced89c7093b43dba8b6"
+checksum = "a994520748611c17d163e81b6c4a4b13d11b7f63884362ab2efac3aa9cf16d00"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1688,6 +1715,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "tinyvec"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53953d2d3a5ad81d9f844a32f14ebb121f50b650cd59d0ee2a07cf13c617efed"
+
+[[package]]
 name = "unicode-bidi"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1698,11 +1731,11 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5479532badd04e128284890390c1e876ef7a993d0570b3597ae43dfa1d59afa4"
+checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
 dependencies = [
- "smallvec",
+ "tinyvec",
 ]
 
 [[package]]
@@ -1730,6 +1763,18 @@ dependencies = [
 ]
 
 [[package]]
+name = "vfs"
+version = "0.1.0"
+dependencies = [
+ "crossbeam-channel",
+ "globset",
+ "jod-thread",
+ "paths",
+ "rustc-hash",
+ "walkdir",
+]
+
+[[package]]
 name = "walkdir"
 version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/crates/paths/src/lib.rs b/crates/paths/src/lib.rs
index c7ce0c42f..190c50913 100644
--- a/crates/paths/src/lib.rs
+++ b/crates/paths/src/lib.rs
@@ -2,7 +2,7 @@
 //! relative paths.
 use std::{
     convert::{TryFrom, TryInto},
-    ops,
+    io, ops,
     path::{Component, Path, PathBuf},
 };
 
@@ -46,6 +46,9 @@ impl TryFrom<&str> for AbsPathBuf {
 }
 
 impl AbsPathBuf {
+    pub fn canonicalized(path: &Path) -> io::Result<AbsPathBuf> {
+        path.canonicalize().map(|it| AbsPathBuf::try_from(it).unwrap())
+    }
     pub fn as_path(&self) -> &AbsPath {
         AbsPath::new_unchecked(self.0.as_path())
     }
diff --git a/crates/ra_assists/src/assist_context.rs b/crates/ra_assists/src/assist_context.rs
index edd8255f4..ee614de72 100644
--- a/crates/ra_assists/src/assist_context.rs
+++ b/crates/ra_assists/src/assist_context.rs
@@ -252,7 +252,7 @@ impl AssistBuilder {
     pub(crate) fn rewrite(&mut self, rewriter: SyntaxRewriter) {
         let node = rewriter.rewrite_root().unwrap();
         let new = rewriter.rewrite(&node);
-        algo::diff(&node, &new).into_text_edit(&mut self.edit)
+        algo::diff(&node, &new).into_text_edit(&mut self.edit);
     }
 
     // FIXME: kill this API
diff --git a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
index 0197a8cf0..b4784c333 100644
--- a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -1,7 +1,10 @@
 use hir;
-use ra_syntax::{ast, AstNode, SmolStr, TextRange};
+use ra_syntax::{algo::SyntaxRewriter, ast, match_ast, AstNode, SmolStr, SyntaxNode};
 
-use crate::{utils::insert_use_statement, AssistContext, AssistId, Assists};
+use crate::{
+    utils::{find_insert_use_container, insert_use_statement},
+    AssistContext, AssistId, Assists,
+};
 
 // Assist: replace_qualified_name_with_use
 //
@@ -39,16 +42,18 @@ pub(crate) fn replace_qualified_name_with_use(
         target,
         |builder| {
             let path_to_import = hir_path.mod_path().clone();
+            let container = match find_insert_use_container(path.syntax(), ctx) {
+                Some(c) => c,
+                None => return,
+            };
             insert_use_statement(path.syntax(), &path_to_import, ctx, builder.text_edit_builder());
 
-            if let Some(last) = path.segment() {
-                // Here we are assuming the assist will provide a correct use statement
-                // so we can delete the path qualifier
-                builder.delete(TextRange::new(
-                    path.syntax().text_range().start(),
-                    last.syntax().text_range().start(),
-                ));
-            }
+            // Now that we've brought the name into scope, re-qualify all paths that could be
+            // affected (that is, all paths inside the node we added the `use` to).
+            let mut rewriter = SyntaxRewriter::default();
+            let syntax = container.either(|l| l.syntax().clone(), |r| r.syntax().clone());
+            shorten_paths(&mut rewriter, syntax, path);
+            builder.rewrite(rewriter);
         },
     )
 }
@@ -73,6 +78,69 @@ fn collect_hir_path_segments(path: &hir::Path) -> Option<Vec<SmolStr>> {
     Some(ps)
 }
 
+/// Adds replacements to `re` that shorten `path` in all descendants of `node`.
+fn shorten_paths(rewriter: &mut SyntaxRewriter<'static>, node: SyntaxNode, path: ast::Path) {
+    for child in node.children() {
+        match_ast! {
+            match child {
+                // Don't modify `use` items, as this can break the `use` item when injecting a new
+                // import into the use tree.
+                ast::UseItem(_it) => continue,
+                // Don't descend into submodules, they don't have the same `use` items in scope.
+                ast::Module(_it) => continue,
+
+                ast::Path(p) => {
+                    match maybe_replace_path(rewriter, p.clone(), path.clone()) {
+                        Some(()) => {},
+                        None => shorten_paths(rewriter, p.syntax().clone(), path.clone()),
+                    }
+                },
+                _ => shorten_paths(rewriter, child, path.clone()),
+            }
+        }
+    }
+}
+
+fn maybe_replace_path(
+    rewriter: &mut SyntaxRewriter<'static>,
+    path: ast::Path,
+    target: ast::Path,
+) -> Option<()> {
+    if !path_eq(path.clone(), target.clone()) {
+        return None;
+    }
+
+    // Shorten `path`, leaving only its last segment.
+    if let Some(parent) = path.qualifier() {
+        rewriter.delete(parent.syntax());
+    }
+    if let Some(double_colon) = path.coloncolon_token() {
+        rewriter.delete(&double_colon);
+    }
+
+    Some(())
+}
+
+fn path_eq(lhs: ast::Path, rhs: ast::Path) -> bool {
+    let mut lhs_curr = lhs;
+    let mut rhs_curr = rhs;
+    loop {
+        match (lhs_curr.segment(), rhs_curr.segment()) {
+            (Some(lhs), Some(rhs)) if lhs.syntax().text() == rhs.syntax().text() => (),
+            _ => return false,
+        }
+
+        match (lhs_curr.qualifier(), rhs_curr.qualifier()) {
+            (Some(lhs), Some(rhs)) => {
+                lhs_curr = lhs;
+                rhs_curr = rhs;
+            }
+            (None, None) => return true,
+            _ => return false,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
@@ -83,10 +151,10 @@ mod tests {
     fn test_replace_add_use_no_anchor() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 std::fmt::Debug<|>
     ",
-            "
+            r"
 use std::fmt::Debug;
 
 Debug
@@ -97,13 +165,13 @@ Debug
     fn test_replace_add_use_no_anchor_with_item_below() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 std::fmt::Debug<|>
 
 fn main() {
 }
     ",
-            "
+            r"
 use std::fmt::Debug;
 
 Debug
@@ -118,13 +186,13 @@ fn main() {
     fn test_replace_add_use_no_anchor_with_item_above() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 fn main() {
 }
 
 std::fmt::Debug<|>
     ",
-            "
+            r"
 use std::fmt::Debug;
 
 fn main() {
@@ -139,10 +207,10 @@ Debug
     fn test_replace_add_use_no_anchor_2seg() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 std::fmt<|>::Debug
     ",
-            "
+            r"
 use std::fmt;
 
 fmt::Debug
@@ -154,13 +222,13 @@ fmt::Debug
     fn test_replace_add_use() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use stdx;
 
 impl std::fmt::Debug<|> for Foo {
 }
     ",
-            "
+            r"
 use stdx;
 use std::fmt::Debug;
 
@@ -174,11 +242,11 @@ impl Debug for Foo {
     fn test_replace_file_use_other_anchor() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 impl std::fmt::Debug<|> for Foo {
 }
     ",
-            "
+            r"
 use std::fmt::Debug;
 
 impl Debug for Foo {
@@ -191,11 +259,11 @@ impl Debug for Foo {
     fn test_replace_add_use_other_anchor_indent() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
     impl std::fmt::Debug<|> for Foo {
     }
     ",
-            "
+            r"
     use std::fmt::Debug;
 
     impl Debug for Foo {
@@ -208,13 +276,13 @@ impl Debug for Foo {
     fn test_replace_split_different() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt;
 
 impl std::io<|> for Foo {
 }
     ",
-            "
+            r"
 use std::{io, fmt};
 
 impl io for Foo {
@@ -227,13 +295,13 @@ impl io for Foo {
     fn test_replace_split_self_for_use() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt;
 
 impl std::fmt::Debug<|> for Foo {
 }
     ",
-            "
+            r"
 use std::fmt::{self, Debug, };
 
 impl Debug for Foo {
@@ -246,13 +314,13 @@ impl Debug for Foo {
     fn test_replace_split_self_for_target() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::Debug;
 
 impl std::fmt<|> for Foo {
 }
     ",
-            "
+            r"
 use std::fmt::{self, Debug};
 
 impl fmt for Foo {
@@ -265,13 +333,13 @@ impl fmt for Foo {
     fn test_replace_add_to_nested_self_nested() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::{Debug, nested::{Display}};
 
 impl std::fmt::nested<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt::{Debug, nested::{Display, self}};
 
 impl nested for Foo {
@@ -284,13 +352,13 @@ impl nested for Foo {
     fn test_replace_add_to_nested_self_already_included() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::{Debug, nested::{self, Display}};
 
 impl std::fmt::nested<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt::{Debug, nested::{self, Display}};
 
 impl nested for Foo {
@@ -303,13 +371,13 @@ impl nested for Foo {
     fn test_replace_add_to_nested_nested() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::{Debug, nested::{Display}};
 
 impl std::fmt::nested::Debug<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt::{Debug, nested::{Display, Debug}};
 
 impl Debug for Foo {
@@ -322,13 +390,13 @@ impl Debug for Foo {
     fn test_replace_split_common_target_longer() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::Debug;
 
 impl std::fmt::nested::Display<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt::{nested::Display, Debug};
 
 impl Display for Foo {
@@ -341,13 +409,13 @@ impl Display for Foo {
     fn test_replace_split_common_use_longer() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt::nested::Debug;
 
 impl std::fmt::Display<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt::{Display, nested::Debug};
 
 impl Display for Foo {
@@ -360,7 +428,7 @@ impl Display for Foo {
     fn test_replace_use_nested_import() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use crate::{
     ty::{Substs, Ty},
     AssocItem,
@@ -368,7 +436,7 @@ use crate::{
 
 fn foo() { crate::ty::lower<|>::trait_env() }
 ",
-            "
+            r"
 use crate::{
     ty::{Substs, Ty, lower},
     AssocItem,
@@ -383,13 +451,13 @@ fn foo() { lower::trait_env() }
     fn test_replace_alias() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt as foo;
 
 impl foo::Debug<|> for Foo {
 }
 ",
-            "
+            r"
 use std::fmt as foo;
 
 impl Debug for Foo {
@@ -402,7 +470,7 @@ impl Debug for Foo {
     fn test_replace_not_applicable_one_segment() {
         check_assist_not_applicable(
             replace_qualified_name_with_use,
-            "
+            r"
 impl foo<|> for Foo {
 }
 ",
@@ -413,7 +481,7 @@ impl foo<|> for Foo {
     fn test_replace_not_applicable_in_use() {
         check_assist_not_applicable(
             replace_qualified_name_with_use,
-            "
+            r"
 use std::fmt<|>;
 ",
         );
@@ -423,14 +491,14 @@ use std::fmt<|>;
     fn test_replace_add_use_no_anchor_in_mod_mod() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 mod foo {
     mod bar {
         std::fmt::Debug<|>
     }
 }
     ",
-            "
+            r"
 mod foo {
     mod bar {
         use std::fmt::Debug;
@@ -446,14 +514,14 @@ mod foo {
     fn inserts_imports_after_inner_attributes() {
         check_assist(
             replace_qualified_name_with_use,
-            "
+            r"
 #![allow(dead_code)]
 
 fn main() {
     std::fmt::Debug<|>
 }
     ",
-            "
+            r"
 #![allow(dead_code)]
 use std::fmt::Debug;
 
@@ -463,4 +531,116 @@ fn main() {
     ",
         );
     }
+
+    #[test]
+    fn replaces_all_affected_paths() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+fn main() {
+    std::fmt::Debug<|>;
+    let x: std::fmt::Debug = std::fmt::Debug;
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+fn main() {
+    Debug;
+    let x: Debug = Debug;
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn replaces_all_affected_paths_mod() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+mod m {
+    fn f() {
+        std::fmt::Debug<|>;
+        let x: std::fmt::Debug = std::fmt::Debug;
+    }
+    fn g() {
+        std::fmt::Debug;
+    }
+}
+
+fn f() {
+    std::fmt::Debug;
+}
+    ",
+            r"
+mod m {
+    use std::fmt::Debug;
+
+    fn f() {
+        Debug;
+        let x: Debug = Debug;
+    }
+    fn g() {
+        Debug;
+    }
+}
+
+fn f() {
+    std::fmt::Debug;
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_in_submodules() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+fn main() {
+    std::fmt::Debug<|>;
+}
+
+mod sub {
+    fn f() {
+        std::fmt::Debug;
+    }
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+fn main() {
+    Debug;
+}
+
+mod sub {
+    fn f() {
+        std::fmt::Debug;
+    }
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_in_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::Display;
+
+fn main() {
+    std::fmt<|>;
+}
+    ",
+            r"
+use std::fmt::{self, Display};
+
+fn main() {
+    fmt;
+}
+    ",
+        );
+    }
 }
diff --git a/crates/ra_assists/src/utils.rs b/crates/ra_assists/src/utils.rs
index 0038a9764..c1ff0de7b 100644
--- a/crates/ra_assists/src/utils.rs
+++ b/crates/ra_assists/src/utils.rs
@@ -13,7 +13,7 @@ use rustc_hash::FxHashSet;
 
 use crate::assist_config::SnippetCap;
 
-pub(crate) use insert_use::insert_use_statement;
+pub(crate) use insert_use::{find_insert_use_container, insert_use_statement};
 
 #[derive(Clone, Copy, Debug)]
 pub(crate) enum Cursor<'a> {
diff --git a/crates/ra_assists/src/utils/insert_use.rs b/crates/ra_assists/src/utils/insert_use.rs
index 0ee43482f..8c4f33e59 100644
--- a/crates/ra_assists/src/utils/insert_use.rs
+++ b/crates/ra_assists/src/utils/insert_use.rs
@@ -12,6 +12,20 @@ use ra_syntax::{
 use ra_text_edit::TextEditBuilder;
 
 use crate::assist_context::AssistContext;
+use either::Either;
+
+/// Determines the containing syntax node in which to insert a `use` statement affecting `position`.
+pub(crate) fn find_insert_use_container(
+    position: &SyntaxNode,
+    ctx: &AssistContext,
+) -> Option<Either<ast::ItemList, ast::SourceFile>> {
+    ctx.sema.ancestors_with_macros(position.clone()).find_map(|n| {
+        if let Some(module) = ast::Module::cast(n.clone()) {
+            return module.item_list().map(|it| Either::Left(it));
+        }
+        Some(Either::Right(ast::SourceFile::cast(n)?))
+    })
+}
 
 /// Creates and inserts a use statement for the given path to import.
 /// The use statement is inserted in the scope most appropriate to the
@@ -24,15 +38,11 @@ pub(crate) fn insert_use_statement(
     builder: &mut TextEditBuilder,
 ) {
     let target = path_to_import.to_string().split("::").map(SmolStr::new).collect::<Vec<_>>();
-    let container = ctx.sema.ancestors_with_macros(position.clone()).find_map(|n| {
-        if let Some(module) = ast::Module::cast(n.clone()) {
-            return module.item_list().map(|it| it.syntax().clone());
-        }
-        ast::SourceFile::cast(n).map(|it| it.syntax().clone())
-    });
+    let container = find_insert_use_container(position, ctx);
 
     if let Some(container) = container {
-        let action = best_action_for_target(container, position.clone(), &target);
+        let syntax = container.either(|l| l.syntax().clone(), |r| r.syntax().clone());
+        let action = best_action_for_target(syntax, position.clone(), &target);
         make_assist(&action, &target, builder);
     }
 }
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index bf26048f2..e6af99035 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -254,12 +254,12 @@ impl CrateGraph {
             return false;
         }
 
+        if target == from {
+            return true;
+        }
+
         for dep in &self[from].dependencies {
             let crate_id = dep.crate_id;
-            if crate_id == target {
-                return true;
-            }
-
             if self.dfs_find(target, crate_id, visited) {
                 return true;
             }
@@ -369,7 +369,7 @@ mod tests {
     use super::{CfgOptions, CrateGraph, CrateName, Dependency, Edition::Edition2018, Env, FileId};
 
     #[test]
-    fn it_should_panic_because_of_cycle_dependencies() {
+    fn detect_cyclic_dependency_indirect() {
         let mut graph = CrateGraph::default();
         let crate1 = graph.add_crate_root(
             FileId(1u32),
@@ -404,6 +404,31 @@ mod tests {
     }
 
     #[test]
+    fn detect_cyclic_dependency_direct() {
+        let mut graph = CrateGraph::default();
+        let crate1 = graph.add_crate_root(
+            FileId(1u32),
+            Edition2018,
+            None,
+            CfgOptions::default(),
+            Env::default(),
+            Default::default(),
+            Default::default(),
+        );
+        let crate2 = graph.add_crate_root(
+            FileId(2u32),
+            Edition2018,
+            None,
+            CfgOptions::default(),
+            Env::default(),
+            Default::default(),
+            Default::default(),
+        );
+        assert!(graph.add_dep(crate1, CrateName::new("crate2").unwrap(), crate2).is_ok());
+        assert!(graph.add_dep(crate2, CrateName::new("crate2").unwrap(), crate2).is_err());
+    }
+
+    #[test]
     fn it_works() {
         let mut graph = CrateGraph::default();
         let crate1 = graph.add_crate_root(
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 1a9f6cc76..ffd5278ec 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -26,8 +26,8 @@ use hir_ty::{
     autoderef,
     display::{HirDisplayError, HirFormatter},
     expr::ExprValidator,
-    method_resolution, ApplicationTy, Canonical, InEnvironment, Substs, TraitEnvironment, Ty,
-    TyDefId, TypeCtor,
+    method_resolution, ApplicationTy, Canonical, GenericPredicate, InEnvironment, Substs,
+    TraitEnvironment, Ty, TyDefId, TypeCtor,
 };
 use ra_db::{CrateId, CrateName, Edition, FileId};
 use ra_prof::profile;
@@ -186,6 +186,22 @@ impl ModuleDef {
 
         module.visibility_of(db, self)
     }
+
+    pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
+        match self {
+            ModuleDef::Adt(it) => Some(it.name(db)),
+            ModuleDef::Trait(it) => Some(it.name(db)),
+            ModuleDef::Function(it) => Some(it.name(db)),
+            ModuleDef::EnumVariant(it) => Some(it.name(db)),
+            ModuleDef::TypeAlias(it) => Some(it.name(db)),
+
+            ModuleDef::Module(it) => it.name(db),
+            ModuleDef::Const(it) => it.name(db),
+            ModuleDef::Static(it) => it.name(db),
+
+            ModuleDef::BuiltinType(it) => Some(it.as_name()),
+        }
+    }
 }
 
 pub use hir_def::{
@@ -1359,6 +1375,27 @@ impl Type {
         Some(adt.into())
     }
 
+    pub fn as_dyn_trait(&self) -> Option<Trait> {
+        self.ty.value.dyn_trait().map(Into::into)
+    }
+
+    pub fn as_impl_traits(&self, db: &dyn HirDatabase) -> Option<Vec<Trait>> {
+        self.ty.value.impl_trait_bounds(db).map(|it| {
+            it.into_iter()
+                .filter_map(|pred| match pred {
+                    hir_ty::GenericPredicate::Implemented(trait_ref) => {
+                        Some(Trait::from(trait_ref.trait_))
+                    }
+                    _ => None,
+                })
+                .collect()
+        })
+    }
+
+    pub fn as_associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<Trait> {
+        self.ty.value.associated_type_parent_trait(db).map(Into::into)
+    }
+
     // FIXME: provide required accessors such that it becomes implementable from outside.
     pub fn is_equal_for_find_impls(&self, other: &Type) -> bool {
         match (&self.ty.value, &other.ty.value) {
@@ -1380,6 +1417,80 @@ impl Type {
             ty: InEnvironment { value: ty, environment: self.ty.environment.clone() },
         }
     }
+
+    pub fn walk(&self, db: &dyn HirDatabase, mut cb: impl FnMut(Type)) {
+        // TypeWalk::walk for a Ty at first visits parameters and only after that the Ty itself.
+        // We need a different order here.
+
+        fn walk_substs(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            substs: &Substs,
+            cb: &mut impl FnMut(Type),
+        ) {
+            for ty in substs.iter() {
+                walk_type(db, &type_.derived(ty.clone()), cb);
+            }
+        }
+
+        fn walk_bounds(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            bounds: &[GenericPredicate],
+            cb: &mut impl FnMut(Type),
+        ) {
+            for pred in bounds {
+                match pred {
+                    GenericPredicate::Implemented(trait_ref) => {
+                        cb(type_.clone());
+                        walk_substs(db, type_, &trait_ref.substs, cb);
+                    }
+                    _ => (),
+                }
+            }
+        }
+
+        fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
+            let ty = type_.ty.value.strip_references();
+            match ty {
+                Ty::Apply(ApplicationTy { ctor, parameters }) => {
+                    match ctor {
+                        TypeCtor::Adt(_) => {
+                            cb(type_.derived(ty.clone()));
+                        }
+                        TypeCtor::AssociatedType(_) => {
+                            if let Some(_) = ty.associated_type_parent_trait(db) {
+                                cb(type_.derived(ty.clone()));
+                            }
+                        }
+                        _ => (),
+                    }
+
+                    // adt params, tuples, etc...
+                    walk_substs(db, type_, parameters, cb);
+                }
+                Ty::Opaque(opaque_ty) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+
+                    walk_substs(db, type_, &opaque_ty.parameters, cb);
+                }
+                Ty::Placeholder(_) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+                }
+                Ty::Dyn(bounds) => {
+                    walk_bounds(db, &type_.derived(ty.clone()), bounds.as_ref(), cb);
+                }
+
+                _ => (),
+            }
+        }
+
+        walk_type(db, self, &mut cb);
+    }
 }
 
 impl HirDisplay for Type {
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index b6b665de1..b25dac28e 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -16,7 +16,7 @@ pub use hir_expand::db::{
 pub use hir_ty::db::{
     AssociatedTyDataQuery, AssociatedTyValueQuery, CallableItemSignatureQuery, FieldTypesQuery,
     GenericDefaultsQuery, GenericPredicatesForParamQuery, GenericPredicatesQuery, HirDatabase,
-    HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, ImplsForTraitQuery,
+    HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, ImplsFromDepsQuery,
     ImplsInCrateQuery, InferQueryQuery, InternAssocTyValueQuery, InternChalkImplQuery,
     InternTypeCtorQuery, InternTypeParamIdQuery, ReturnTypeImplTraitsQuery, StructDatumQuery,
     TraitDatumQuery, TraitSolveQuery, TyQuery, ValueTyQuery,
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index a232a5856..6a49c424a 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -6,9 +6,9 @@ use std::{cell::RefCell, fmt, iter::successors};
 
 use hir_def::{
     resolver::{self, HasResolver, Resolver},
-    AsMacroCall, TraitId,
+    AsMacroCall, TraitId, VariantId,
 };
-use hir_expand::{hygiene::Hygiene, ExpansionInfo};
+use hir_expand::{diagnostics::AstDiagnostic, hygiene::Hygiene, ExpansionInfo};
 use hir_ty::associated_type_shorthand_candidates;
 use itertools::Itertools;
 use ra_db::{FileId, FileRange};
@@ -104,6 +104,13 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         tree
     }
 
+    pub fn ast<T: AstDiagnostic + Diagnostic>(&self, d: &T) -> <T as AstDiagnostic>::AST {
+        let file_id = d.source().file_id;
+        let root = self.db.parse_or_expand(file_id).unwrap();
+        self.cache(root, file_id);
+        d.ast(self.db)
+    }
+
     pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         let macro_call = self.find_file(macro_call.syntax().clone()).with_value(macro_call);
         let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
@@ -247,6 +254,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.analyze(path.syntax()).resolve_path(self.db, path)
     }
 
+    pub fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantId> {
+        self.analyze(record_lit.syntax()).resolve_variant(self.db, record_lit)
+    }
+
     pub fn lower_path(&self, path: &ast::Path) -> Option<Path> {
         let src = self.find_file(path.syntax().clone());
         Path::from_src(path.clone(), &Hygiene::new(self.db.upcast(), src.file_id.into()))
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index 7c6bbea13..757d1e397 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -313,6 +313,16 @@ impl SourceAnalyzer {
         })?;
         Some(macro_call_id.as_file())
     }
+
+    pub(crate) fn resolve_variant(
+        &self,
+        db: &dyn HirDatabase,
+        record_lit: ast::RecordLit,
+    ) -> Option<VariantId> {
+        let infer = self.infer.as_ref()?;
+        let expr_id = self.expr_id(db, &record_lit.into())?;
+        infer.variant_resolution_for_expr(expr_id)
+    }
 }
 
 fn scope_for(
diff --git a/crates/ra_hir_def/src/body/scope.rs b/crates/ra_hir_def/src/body/scope.rs
index e48ff38f9..661f00407 100644
--- a/crates/ra_hir_def/src/body/scope.rs
+++ b/crates/ra_hir_def/src/body/scope.rs
@@ -87,15 +87,13 @@ impl ExprScopes {
     }
 
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
-        match &body[pat] {
-            Pat::Bind { name, .. } => {
-                // bind can have a sub pattern, but it's actually not allowed
-                // to bind to things in there
-                let entry = ScopeEntry { name: name.clone(), pat };
-                self.scopes[scope].entries.push(entry)
-            }
-            p => p.walk_child_pats(|pat| self.add_bindings(body, scope, pat)),
+        let pattern = &body[pat];
+        if let Pat::Bind { name, .. } = pattern {
+            let entry = ScopeEntry { name: name.clone(), pat };
+            self.scopes[scope].entries.push(entry);
         }
+
+        pattern.walk_child_pats(|pat| self.add_bindings(body, scope, pat));
     }
 
     fn add_params_bindings(&mut self, body: &Body, scope: ScopeId, params: &[PatId]) {
@@ -190,8 +188,8 @@ mod tests {
         }
     }
 
-    fn do_check(code: &str, expected: &[&str]) {
-        let (off, code) = extract_offset(code);
+    fn do_check(ra_fixture: &str, expected: &[&str]) {
+        let (off, code) = extract_offset(ra_fixture);
         let code = {
             let mut buf = String::new();
             let off: usize = off.into();
@@ -300,6 +298,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_bindings_after_at() {
+        do_check(
+            r"
+            fn foo() {
+                match Some(()) {
+                    opt @ Some(unit) => {
+                        <|>
+                    }
+                    _ => {}
+                }
+            }",
+            &["opt", "unit"],
+        );
+    }
+
     fn do_check_local_name(code: &str, expected_offset: u32) {
         let (off, code) = extract_offset(code);
 
diff --git a/crates/ra_hir_def/src/diagnostics.rs b/crates/ra_hir_def/src/diagnostics.rs
index 510c5e064..30db48f86 100644
--- a/crates/ra_hir_def/src/diagnostics.rs
+++ b/crates/ra_hir_def/src/diagnostics.rs
@@ -3,7 +3,6 @@
 use std::any::Any;
 
 use hir_expand::diagnostics::Diagnostic;
-use ra_db::RelativePathBuf;
 use ra_syntax::{ast, AstPtr, SyntaxNodePtr};
 
 use hir_expand::{HirFileId, InFile};
@@ -12,7 +11,7 @@ use hir_expand::{HirFileId, InFile};
 pub struct UnresolvedModule {
     pub file: HirFileId,
     pub decl: AstPtr<ast::Module>,
-    pub candidate: RelativePathBuf,
+    pub candidate: String,
 }
 
 impl Diagnostic for UnresolvedModule {
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index edc59e5a8..af2a717c9 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -159,7 +159,7 @@ pub struct TypeAliasId(salsa::InternId);
 type TypeAliasLoc = AssocItemLoc<ast::TypeAliasDef>;
 impl_intern!(TypeAliasId, TypeAliasLoc, intern_type_alias, lookup_intern_type_alias);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub struct ImplId(salsa::InternId);
 type ImplLoc = ItemLoc<ast::ImplDef>;
 impl_intern!(ImplId, ImplLoc, intern_impl, lookup_intern_impl);
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index f279c2ad4..b8560fdc9 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -119,13 +119,6 @@ impl Default for ModuleOrigin {
 }
 
 impl ModuleOrigin {
-    pub(crate) fn not_sure_file(file: Option<FileId>, declaration: AstId<ast::Module>) -> Self {
-        match file {
-            None => ModuleOrigin::Inline { definition: declaration },
-            Some(definition) => ModuleOrigin::File { declaration, definition },
-        }
-    }
-
     fn declaration(&self) -> Option<AstId<ast::Module>> {
         match self {
             ModuleOrigin::File { declaration: module, .. }
@@ -296,7 +289,6 @@ pub enum ModuleSource {
 
 mod diagnostics {
     use hir_expand::diagnostics::DiagnosticSink;
-    use ra_db::RelativePathBuf;
     use ra_syntax::{ast, AstPtr};
 
     use crate::{db::DefDatabase, diagnostics::UnresolvedModule, nameres::LocalModuleId, AstId};
@@ -306,7 +298,7 @@ mod diagnostics {
         UnresolvedModule {
             module: LocalModuleId,
             declaration: AstId<ast::Module>,
-            candidate: RelativePathBuf,
+            candidate: String,
         },
     }
 
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 976e5e585..b8f6aac8f 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -36,8 +36,8 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: CrateDefMap) -> Cr
 
     // populate external prelude
     for dep in &crate_graph[def_map.krate].dependencies {
-        let dep_def_map = db.crate_def_map(dep.crate_id);
         log::debug!("crate dep {:?} -> {:?}", dep.name, dep.crate_id);
+        let dep_def_map = db.crate_def_map(dep.crate_id);
         def_map.extern_prelude.insert(
             dep.as_name(),
             ModuleId { krate: dep.crate_id, local_id: dep_def_map.root }.into(),
@@ -825,7 +825,10 @@ impl ModCollector<'_, '_> {
         let modules = &mut self.def_collector.def_map.modules;
         let res = modules.alloc(ModuleData::default());
         modules[res].parent = Some(self.module_id);
-        modules[res].origin = ModuleOrigin::not_sure_file(definition, declaration);
+        modules[res].origin = match definition {
+            None => ModuleOrigin::Inline { definition: declaration },
+            Some(definition) => ModuleOrigin::File { declaration, definition },
+        };
         for (name, mac) in modules[self.module_id].scope.collect_legacy_macros() {
             modules[res].scope.define_legacy_macro(name, mac)
         }
diff --git a/crates/ra_hir_def/src/nameres/mod_resolution.rs b/crates/ra_hir_def/src/nameres/mod_resolution.rs
index cede4a6fc..19fe0615a 100644
--- a/crates/ra_hir_def/src/nameres/mod_resolution.rs
+++ b/crates/ra_hir_def/src/nameres/mod_resolution.rs
@@ -44,7 +44,7 @@ impl ModDir {
         file_id: HirFileId,
         name: &Name,
         attr_path: Option<&SmolStr>,
-    ) -> Result<(FileId, ModDir), RelativePathBuf> {
+    ) -> Result<(FileId, ModDir), String> {
         let file_id = file_id.original_file(db.upcast());
 
         let mut candidate_files = Vec::new();
@@ -52,11 +52,11 @@ impl ModDir {
             Some(attr_path) => {
                 let base =
                     if self.root_non_dir_owner { self.path.parent().unwrap() } else { &self.path };
-                candidate_files.push(base.join(attr_path))
+                candidate_files.push(base.join(attr_path).to_string())
             }
             None => {
-                candidate_files.push(self.path.join(&format!("{}.rs", name)));
-                candidate_files.push(self.path.join(&format!("{}/mod.rs", name)));
+                candidate_files.push(self.path.join(&format!("{}.rs", name)).to_string());
+                candidate_files.push(self.path.join(&format!("{}/mod.rs", name)).to_string());
             }
         };
 
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index fff257193..5495ce284 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -312,20 +312,16 @@ impl PatStack {
         Self(v)
     }
 
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-
-    fn head(&self) -> PatIdOrWild {
-        self.0[0]
-    }
-
     fn get_head(&self) -> Option<PatIdOrWild> {
         self.0.first().copied()
     }
 
+    fn tail(&self) -> &[PatIdOrWild] {
+        self.0.get(1..).unwrap_or(&[])
+    }
+
     fn to_tail(&self) -> PatStack {
-        Self::from_slice(&self.0[1..])
+        Self::from_slice(self.tail())
     }
 
     fn replace_head_with<I, T>(&self, pats: I) -> PatStack
@@ -347,7 +343,7 @@ impl PatStack {
     ///
     /// See the module docs and the associated documentation in rustc for details.
     fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Option<PatStack> {
-        if matches!(self.head().as_pat(cx), Pat::Wild) {
+        if matches!(self.get_head()?.as_pat(cx), Pat::Wild) {
             Some(self.to_tail())
         } else {
             None
@@ -362,7 +358,13 @@ impl PatStack {
         cx: &MatchCheckCtx,
         constructor: &Constructor,
     ) -> MatchCheckResult<Option<PatStack>> {
-        let result = match (self.head().as_pat(cx), constructor) {
+        let head = match self.get_head() {
+            Some(head) => head,
+            None => return Ok(None),
+        };
+
+        let head_pat = head.as_pat(cx);
+        let result = match (head_pat, constructor) {
             (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => {
                 if ellipsis.is_some() {
                     // If there are ellipsis here, we should add the correct number of
@@ -389,7 +391,7 @@ impl PatStack {
             (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?),
             (Pat::Path(_), Constructor::Enum(constructor)) => {
                 // unit enum variants become `Pat::Path`
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *constructor) {
                     None
                 } else {
@@ -400,7 +402,7 @@ impl PatStack {
                 Pat::TupleStruct { args: ref pat_ids, ellipsis, .. },
                 Constructor::Enum(enum_constructor),
             ) => {
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *enum_constructor) {
                     None
                 } else {
@@ -440,7 +442,7 @@ impl PatStack {
                 }
             }
             (Pat::Record { args: ref arg_patterns, .. }, Constructor::Enum(e)) => {
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *e) {
                     None
                 } else {
@@ -486,7 +488,7 @@ impl PatStack {
     ) -> MatchCheckResult<PatStack> {
         assert_eq!(
             Pat::Wild,
-            self.head().as_pat(cx),
+            self.get_head().expect("expand_wildcard called on empty PatStack").as_pat(cx),
             "expand_wildcard must only be called on PatStack with wild at head",
         );
 
@@ -504,7 +506,6 @@ impl PatStack {
     }
 }
 
-#[derive(Debug)]
 /// A collection of PatStack.
 ///
 /// This type is modeled from the struct of the same name in `rustc`.
@@ -531,7 +532,7 @@ impl Matrix {
     }
 
     fn heads(&self) -> Vec<PatIdOrWild> {
-        self.0.iter().map(|p| p.head()).collect()
+        self.0.iter().flat_map(|p| p.get_head()).collect()
     }
 
     /// Computes `D(self)` for each contained PatStack.
@@ -618,13 +619,16 @@ pub(crate) fn is_useful(
         _ => (),
     }
 
-    if v.is_empty() {
-        let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful };
+    let head = match v.get_head() {
+        Some(head) => head,
+        None => {
+            let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful };
 
-        return Ok(result);
-    }
+            return Ok(result);
+        }
+    };
 
-    if let Pat::Or(pat_ids) = v.head().as_pat(cx) {
+    if let Pat::Or(pat_ids) = head.as_pat(cx) {
         let mut found_unimplemented = false;
         let any_useful = pat_ids.iter().any(|&pat_id| {
             let v = PatStack::from_pattern(pat_id);
@@ -648,7 +652,7 @@ pub(crate) fn is_useful(
         };
     }
 
-    if let Some(constructor) = pat_constructor(cx, v.head())? {
+    if let Some(constructor) = pat_constructor(cx, head)? {
         let matrix = matrix.specialize_constructor(&cx, &constructor)?;
         let v = v
             .specialize_constructor(&cx, &constructor)?
@@ -837,194 +841,193 @@ mod tests {
 
     pub(super) use crate::{diagnostics::MissingMatchArms, test_db::TestDB};
 
-    pub(super) fn check_diagnostic_message(content: &str) -> String {
-        TestDB::with_single_file(content).0.diagnostic::<MissingMatchArms>().0
+    pub(super) fn check_diagnostic_message(ra_fixture: &str) -> String {
+        TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().0
     }
 
-    pub(super) fn check_diagnostic(content: &str) {
+    pub(super) fn check_diagnostic(ra_fixture: &str) {
         let diagnostic_count =
-            TestDB::with_single_file(content).0.diagnostic::<MissingMatchArms>().1;
+            TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().1;
 
         assert_eq!(1, diagnostic_count, "no diagnostic reported");
     }
 
-    pub(super) fn check_no_diagnostic(content: &str) {
-        let diagnostic_count =
-            TestDB::with_single_file(content).0.diagnostic::<MissingMatchArms>().1;
+    pub(super) fn check_no_diagnostic(ra_fixture: &str) {
+        let (s, diagnostic_count) =
+            TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>();
 
-        assert_eq!(0, diagnostic_count, "expected no diagnostic, found one");
+        assert_eq!(0, diagnostic_count, "expected no diagnostic, found one: {}", s);
     }
 
     #[test]
     fn empty_tuple_no_arms_diagnostic_message() {
-        let content = r"
-            fn test_fn() {
-                match () {
-                }
-            }
-        ";
-
         assert_snapshot!(
-            check_diagnostic_message(content),
+            check_diagnostic_message(r"
+                fn test_fn() {
+                    match () {
+                    }
+                }
+            "),
             @"\"()\": Missing match arm\n"
         );
     }
 
     #[test]
     fn empty_tuple_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match () {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn empty_tuple_wild() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match () {
                     _ => {}
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn empty_tuple_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match () {
                     () => {}
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_empty_tuple_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (()) {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_empty_tuple_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (()) {
                     (()) => {}
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_two_empty_tuple_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match ((), ()) {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_two_empty_tuple_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match ((), ()) {
                     ((), ()) => {}
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn bool_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match false {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn bool_missing_arm() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match false {
                     true => {}
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn bool_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match false {
                     true => {}
                     false => {}
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (true, true) => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_missing_arm() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (false, true) => {},
@@ -1032,14 +1035,14 @@ mod tests {
                     (true, false) => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_wilds() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (false, _) => {},
@@ -1047,14 +1050,14 @@ mod tests {
                     (_, true) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (true, true) => {},
@@ -1063,27 +1066,27 @@ mod tests {
                     (false, false) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_binding_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (true, _x) => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_binding_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true) {
                     (true, _x) => {},
@@ -1091,80 +1094,80 @@ mod tests {
                     (false, false) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_ellipsis_at_end_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true, false) {
                     (false, ..) => {},
                     (true, ..) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_ellipsis_at_beginning_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true, false) {
                     (.., false) => {},
                     (.., true) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_ellipsis_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true, false) {
                     (..) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_tuple_and_bools_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, ((), false)) {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_tuple_and_bools_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, ((), false)) {
                     (true, ((), true)) => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_tuple_and_bools_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, ((), false)) {
                     (true, ((), true)) => {},
@@ -1173,27 +1176,27 @@ mod tests {
                     (false, ((), false)) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_tuple_and_bools_wildcard_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             fn test_fn() {
                 match (false, ((), false)) {
                     (true, _) => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_tuple_and_bools_wildcard_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, ((), false)) {
                     (true, ((), true)) => {},
@@ -1201,14 +1204,14 @@ mod tests {
                     (false, _) => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1217,14 +1220,14 @@ mod tests {
                 match Either::A {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1234,14 +1237,14 @@ mod tests {
                     Either::A => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1252,14 +1255,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_ref_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1269,14 +1272,14 @@ mod tests {
                     Either::A => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_ref_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1287,14 +1290,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_containing_bool_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B,
@@ -1303,14 +1306,14 @@ mod tests {
                 match Either::B {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_containing_bool_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B,
@@ -1321,14 +1324,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_containing_bool_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B,
@@ -1340,14 +1343,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_containing_bool_with_wild_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B,
@@ -1358,14 +1361,14 @@ mod tests {
                     _ => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_containing_bool_with_wild_2_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B,
@@ -1376,14 +1379,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_different_sizes_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B(bool, bool),
@@ -1394,14 +1397,14 @@ mod tests {
                     Either::B(false, _) => (),
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_different_sizes_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B(bool, bool),
@@ -1413,14 +1416,14 @@ mod tests {
                     Either::B(false, _) => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn or_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B(bool, bool),
@@ -1432,14 +1435,14 @@ mod tests {
                     Either::B(false, _) => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_enum_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool),
                 B(bool, bool),
@@ -1456,14 +1459,16 @@ mod tests {
                     (Either::B(_, _), Either2::D) => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn mismatched_types() {
-        let content = r"
+        // Match statements with arms that don't match the
+        // expression pattern do not fire this diagnostic.
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1478,47 +1483,47 @@ mod tests {
                     Either2::D => (),
                 }
             }
-        ";
-
-        // Match statements with arms that don't match the
-        // expression pattern do not fire this diagnostic.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn mismatched_types_with_different_arity() {
-        let content = r"
+        // Match statements with arms that don't match the
+        // expression pattern do not fire this diagnostic.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (true, false) {
                     (true, false, true) => (),
                     (true) => (),
                 }
             }
-        ";
-
-        // Match statements with arms that don't match the
-        // expression pattern do not fire this diagnostic.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn malformed_match_arm_tuple_missing_pattern() {
-        let content = r"
+        // Match statements with arms that don't match the
+        // expression pattern do not fire this diagnostic.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (0) {
                     () => (),
                 }
             }
-        ";
-
-        // Match statements with arms that don't match the
-        // expression pattern do not fire this diagnostic.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn malformed_match_arm_tuple_enum_missing_pattern() {
-        let content = r"
+        // We are testing to be sure we don't panic here when the match
+        // arm `Either::B` is missing its pattern.
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B(u32),
@@ -1529,32 +1534,30 @@ mod tests {
                     Either::B() => (),
                 }
             }
-        ";
-
-        // We are testing to be sure we don't panic here when the match
-        // arm `Either::B` is missing its pattern.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_not_in_scope() {
-        let content = r"
+        // The enum is not in scope so we don't perform exhaustiveness
+        // checking, but we want to be sure we don't panic here (and
+        // we don't create a diagnostic).
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match Foo::Bar {
                     Foo::Baz => (),
                 }
             }
-        ";
-
-        // The enum is not in scope so we don't perform exhaustiveness
-        // checking, but we want to be sure we don't panic here (and
-        // we don't create a diagnostic).
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn expr_diverges() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1565,14 +1568,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn expr_loop_with_break() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1583,14 +1586,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn expr_partially_diverges() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either<T> {
                 A(T),
                 B,
@@ -1604,14 +1607,14 @@ mod tests {
                     Either::B => 0,
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_no_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1621,14 +1624,14 @@ mod tests {
                 match a {
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_missing_arms() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1639,14 +1642,14 @@ mod tests {
                     Either::A { foo: true } => (),
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1659,14 +1662,17 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_missing_field_no_diagnostic() {
-        let content = r"
+        // When `Either::A` is missing a struct member, we don't want
+        // to fire the missing match arm diagnostic. This should fire
+        // some other diagnostic.
+        check_no_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1678,17 +1684,16 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        // When `Either::A` is missing a struct member, we don't want
-        // to fire the missing match arm diagnostic. This should fire
-        // some other diagnostic.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_missing_field_missing_match_arm() {
-        let content = r"
+        // Even though `Either::A` is missing fields, we still want to fire
+        // the missing arm diagnostic here, since we know `Either::B` is missing.
+        check_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1699,16 +1704,14 @@ mod tests {
                     Either::A { } => (),
                 }
             }
-        ";
-
-        // Even though `Either::A` is missing fields, we still want to fire
-        // the missing arm diagnostic here, since we know `Either::B` is missing.
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_no_diagnostic_wild() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A { foo: bool },
                 B,
@@ -1720,14 +1723,14 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_fields_out_of_order_missing_arm() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A { foo: bool, bar: () },
                 B,
@@ -1739,14 +1742,14 @@ mod tests {
                     Either::A { foo: true, bar: () } => (),
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_fields_out_of_order_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A { foo: bool, bar: () },
                 B,
@@ -1759,89 +1762,89 @@ mod tests {
                     Either::B => (),
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_record_ellipsis_missing_arm() {
-        let content = r"
-             enum Either {
-                 A { foo: bool, bar: bool },
-                 B,
-             }
-             fn test_fn() {
-                 match Either::B {
-                     Either::A { foo: true, .. } => (),
-                     Either::B => (),
-                 }
-             }
-         ";
-
-        check_diagnostic(content);
+        check_diagnostic(
+            r"
+            enum Either {
+                A { foo: bool, bar: bool },
+                B,
+            }
+            fn test_fn() {
+                match Either::B {
+                    Either::A { foo: true, .. } => (),
+                    Either::B => (),
+                }
+            }
+        ",
+        );
     }
 
     #[test]
     fn enum_record_ellipsis_no_diagnostic() {
-        let content = r"
-             enum Either {
-                 A { foo: bool, bar: bool },
-                 B,
-             }
-             fn test_fn() {
-                 let a = Either::A { foo: true };
-                 match a {
-                     Either::A { foo: true, .. } => (),
-                     Either::A { foo: false, .. } => (),
-                     Either::B => (),
-                 }
-             }
-         ";
-
-        check_no_diagnostic(content);
+        check_no_diagnostic(
+            r"
+            enum Either {
+                A { foo: bool, bar: bool },
+                B,
+            }
+            fn test_fn() {
+                let a = Either::A { foo: true };
+                match a {
+                    Either::A { foo: true, .. } => (),
+                    Either::A { foo: false, .. } => (),
+                    Either::B => (),
+                }
+            }
+        ",
+        );
     }
 
     #[test]
     fn enum_record_ellipsis_all_fields_missing_arm() {
-        let content = r"
-             enum Either {
-                 A { foo: bool, bar: bool },
-                 B,
-             }
-             fn test_fn() {
-                 let a = Either::B;
-                 match a {
-                     Either::A { .. } => (),
-                 }
-             }
-         ";
-
-        check_diagnostic(content);
+        check_diagnostic(
+            r"
+            enum Either {
+                A { foo: bool, bar: bool },
+                B,
+            }
+            fn test_fn() {
+                let a = Either::B;
+                match a {
+                    Either::A { .. } => (),
+                }
+            }
+        ",
+        );
     }
 
     #[test]
     fn enum_record_ellipsis_all_fields_no_diagnostic() {
-        let content = r"
-             enum Either {
-                 A { foo: bool, bar: bool },
-                 B,
-             }
-             fn test_fn() {
-                 let a = Either::B;
-                 match a {
-                     Either::A { .. } => (),
-                     Either::B => (),
-                 }
-             }
-         ";
-
-        check_no_diagnostic(content);
+        check_no_diagnostic(
+            r"
+            enum Either {
+                A { foo: bool, bar: bool },
+                B,
+            }
+            fn test_fn() {
+                let a = Either::B;
+                match a {
+                    Either::A { .. } => (),
+                    Either::B => (),
+                }
+            }
+        ",
+        );
     }
 
     #[test]
     fn enum_tuple_partial_ellipsis_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool, bool, bool, bool),
                 B,
@@ -1855,14 +1858,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_tuple_partial_ellipsis_2_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool, bool, bool, bool),
                 B,
@@ -1876,14 +1879,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_tuple_partial_ellipsis_missing_arm() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A(bool, bool, bool, bool),
                 B,
@@ -1896,14 +1899,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_tuple_partial_ellipsis_2_missing_arm() {
-        let content = r"
+        check_diagnostic(
+            r"
             enum Either {
                 A(bool, bool, bool, bool),
                 B,
@@ -1916,14 +1919,14 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_tuple_ellipsis_no_diagnostic() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A(bool, bool, bool, bool),
                 B,
@@ -1934,51 +1937,51 @@ mod tests {
                     Either::B => {},
                 }
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_never() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Never {}
 
             fn test_fn(never: Never) {
                 match never {}
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn type_never() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             fn test_fn(never: !) {
                 match never {}
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn enum_never_ref() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Never {}
 
             fn test_fn(never: &Never) {
                 match never {}
             }
-        ";
-
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn expr_diverges_missing_arm() {
-        let content = r"
+        check_no_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -1988,9 +1991,49 @@ mod tests {
                     Either::A => (),
                 }
             }
-        ";
+        ",
+        );
+    }
 
-        check_no_diagnostic(content);
+    #[test]
+    fn or_pattern_panic() {
+        check_no_diagnostic(
+            r"
+            pub enum Category {
+                Infinity,
+                Zero,
+            }
+
+            fn panic(a: Category, b: Category) {
+                match (a, b) {
+                    (Category::Zero | Category::Infinity, _) => {}
+                    (_, Category::Zero | Category::Infinity) => {}
+                }
+            }
+        ",
+        );
+    }
+
+    #[test]
+    fn or_pattern_panic_2() {
+        // FIXME: This is a false positive, but the code used to cause a panic in the match checker,
+        // so this acts as a regression test for that.
+        check_diagnostic(
+            r"
+            pub enum Category {
+                Infinity,
+                Zero,
+            }
+
+            fn panic(a: Category, b: Category) {
+                match (a, b) {
+                    (Category::Infinity, Category::Infinity) | (Category::Zero, Category::Zero) => {}
+
+                    (Category::Infinity | Category::Zero, _) => {}
+                }
+            }
+        ",
+        );
     }
 }
 
@@ -2010,23 +2053,26 @@ mod false_negatives {
 
     #[test]
     fn integers() {
-        let content = r"
+        // This is a false negative.
+        // We don't currently check integer exhaustiveness.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match 5 {
                     10 => (),
                     11..20 => (),
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We don't currently check integer exhaustiveness.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn internal_or() {
-        let content = r"
+        // This is a false negative.
+        // We do not currently handle patterns with internal `or`s.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 enum Either {
                     A(bool),
@@ -2036,16 +2082,18 @@ mod false_negatives {
                     Either::A(true | false) => (),
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We do not currently handle patterns with internal `or`s.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn expr_loop_missing_arm() {
-        let content = r"
+        // This is a false negative.
+        // We currently infer the type of `loop { break Foo::A }` to `!`, which
+        // causes us to skip the diagnostic since `Either::A` doesn't type check
+        // with `!`.
+        check_diagnostic(
+            r"
             enum Either {
                 A,
                 B,
@@ -2055,48 +2103,46 @@ mod false_negatives {
                     Either::A => (),
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We currently infer the type of `loop { break Foo::A }` to `!`, which
-        // causes us to skip the diagnostic since `Either::A` doesn't type check
-        // with `!`.
-        check_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_ellipsis_at_end_missing_arm() {
-        let content = r"
+        // This is a false negative.
+        // We don't currently handle tuple patterns with ellipsis.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true, false) {
                     (false, ..) => {},
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We don't currently handle tuple patterns with ellipsis.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn tuple_of_bools_with_ellipsis_at_beginning_missing_arm() {
-        let content = r"
+        // This is a false negative.
+        // We don't currently handle tuple patterns with ellipsis.
+        check_no_diagnostic(
+            r"
             fn test_fn() {
                 match (false, true, false) {
                     (.., false) => {},
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We don't currently handle tuple patterns with ellipsis.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 
     #[test]
     fn struct_missing_arm() {
-        let content = r"
+        // This is a false negative.
+        // We don't currently handle structs.
+        check_no_diagnostic(
+            r"
             struct Foo {
                 a: bool,
             }
@@ -2105,10 +2151,7 @@ mod false_negatives {
                     Foo { a: true } => {},
                 }
             }
-        ";
-
-        // This is a false negative.
-        // We don't currently handle structs.
-        check_no_diagnostic(content);
+        ",
+        );
     }
 }
diff --git a/crates/ra_hir_ty/src/db.rs b/crates/ra_hir_ty/src/db.rs
index bf71d38d6..7889b8d2c 100644
--- a/crates/ra_hir_ty/src/db.rs
+++ b/crates/ra_hir_ty/src/db.rs
@@ -3,15 +3,15 @@
 use std::sync::Arc;
 
 use hir_def::{
-    db::DefDatabase, DefWithBodyId, FunctionId, GenericDefId, ImplId, LocalFieldId, TraitId,
-    TypeParamId, VariantId,
+    db::DefDatabase, DefWithBodyId, FunctionId, GenericDefId, ImplId, LocalFieldId, TypeParamId,
+    VariantId,
 };
 use ra_arena::map::ArenaMap;
 use ra_db::{impl_intern_key, salsa, CrateId, Upcast};
 use ra_prof::profile;