diff --git a/pkgs/development/tools/rust/rust-analyzer/default.nix b/pkgs/development/tools/rust/rust-analyzer/default.nix
index 5d66f6e21007..7a2586f01389 100644
--- a/pkgs/development/tools/rust/rust-analyzer/default.nix
+++ b/pkgs/development/tools/rust/rust-analyzer/default.nix
@@ -2,10 +2,10 @@
 
 {
   rust-analyzer-unwrapped = callPackage ./generic.nix rec {
-    rev = "2020-09-21";
+    rev = "2020-09-28";
     version = "unstable-${rev}";
-    sha256 = "1wjm69r1c6s8a4rd91csg7c48bp8jamxsrm5m6rg3bk2gqp8yzz8";
-    cargoSha256 = "089w2i6lvpjxkxghkb2mij9sxfxlcc1zv4iq4qmzq8gnc6ddz12d";
+    sha256 = "1ynwrkdy78105xbrcynk0qimk90y849hn54sw8q3akdlyfx1kdrs";
+    cargoSha256 = "0iy7h3q7dp2nbfzzg7yc8zbkb5npghz8l15d83xd8w8q39i3qff5";
   };
 
   rust-analyzer = callPackage ./wrapper.nix {} {
diff --git a/pkgs/development/tools/rust/rust-analyzer/downgrade-smol_str.patch b/pkgs/development/tools/rust/rust-analyzer/downgrade-smol_str.patch
new file mode 100644
index 000000000000..c3ceb0963336
--- /dev/null
+++ b/pkgs/development/tools/rust/rust-analyzer/downgrade-smol_str.patch
@@ -0,0 +1,82 @@
+This patch revert 875ad9b5c410200f5072515ae91b4ff51cff0448 (Bump smol_str from 0.1.16 to 0.1.17 ).
+
+diff --git a/Cargo.lock b/Cargo.lock
+index 477af57aa..8b9055879 100644
+--- a/Cargo.lock
++++ b/Cargo.lock
+@@ -1470,9 +1470,9 @@ checksum = "fbee7696b84bbf3d89a1c2eccff0850e3047ed46bfcd2e92c29a2d074d57e252"
+
+ [[package]]
+ name = "smol_str"
+-version = "0.1.17"
++version = "0.1.16"
+ source = "registry+https://github.com/rust-lang/crates.io-index"
+-checksum = "6ca0f7ce3a29234210f0f4f0b56f8be2e722488b95cb522077943212da3b32eb"
++checksum = "2f7909a1d8bc166a862124d84fdc11bda0ea4ed3157ccca662296919c2972db1"
+ dependencies = [
+  "serde",
+ ]
+diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
+index a5750d829..49841c7a1 100644
+--- a/crates/hir_expand/src/name.rs
++++ b/crates/hir_expand/src/name.rs
+@@ -43,8 +43,8 @@ impl Name {
+     }
+
+     /// Shortcut to create inline plain text name
+-    const fn new_inline(text: &str) -> Name {
+-        Name::new_text(SmolStr::new_inline(text))
++    const fn new_inline_ascii(text: &[u8]) -> Name {
++        Name::new_text(SmolStr::new_inline_from_ascii(text.len(), text))
+     }
+
+     /// Resolve a name from the text of token.
+@@ -127,7 +127,7 @@ pub mod known {
+             $(
+                 #[allow(bad_style)]
+                 pub const $ident: super::Name =
+-                    super::Name::new_inline(stringify!($ident));
++                    super::Name::new_inline_ascii(stringify!($ident).as_bytes());
+             )*
+         };
+     }
+@@ -210,8 +210,8 @@ pub mod known {
+     );
+
+     // self/Self cannot be used as an identifier
+-    pub const SELF_PARAM: super::Name = super::Name::new_inline("self");
+-    pub const SELF_TYPE: super::Name = super::Name::new_inline("Self");
++    pub const SELF_PARAM: super::Name = super::Name::new_inline_ascii(b"self");
++    pub const SELF_TYPE: super::Name = super::Name::new_inline_ascii(b"Self");
+
+     #[macro_export]
+     macro_rules! name {
+diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
+index 9a7785c76..2b53b8297 100644
+--- a/crates/hir_ty/src/infer.rs
++++ b/crates/hir_ty/src/infer.rs
+@@ -555,7 +555,7 @@ impl<'a> InferenceContext<'a> {
+
+     fn resolve_lang_item(&self, name: &str) -> Option<LangItemTarget> {
+         let krate = self.resolver.krate()?;
+-        let name = SmolStr::new_inline(name);
++        let name = SmolStr::new_inline_from_ascii(name.len(), name.as_bytes());
+         self.db.lang_item(krate, name)
+     }
+
+diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
+index d987b2500..a8ad917fb 100644
+--- a/crates/mbe/src/syntax_bridge.rs
++++ b/crates/mbe/src/syntax_bridge.rs
+@@ -636,10 +636,7 @@ impl<'a> TreeSink for TtTreeSink<'a> {
+                     let (text, id) = match leaf {
+                         tt::Leaf::Ident(ident) => (ident.text.clone(), ident.id),
+                         tt::Leaf::Punct(punct) => {
+-                            assert!(punct.char.is_ascii());
+-                            let char = &(punct.char as u8);
+-                            let text = std::str::from_utf8(std::slice::from_ref(char)).unwrap();
+-                            (SmolStr::new_inline(text), punct.id)
++                            (SmolStr::new_inline_from_ascii(1, &[punct.char as u8]), punct.id)
+                         }
+                         tt::Leaf::Literal(lit) => (lit.text.clone(), lit.id),
+                     };
diff --git a/pkgs/development/tools/rust/rust-analyzer/generic.nix b/pkgs/development/tools/rust/rust-analyzer/generic.nix
index 3bd6d1ccee14..20fb38b66b70 100644
--- a/pkgs/development/tools/rust/rust-analyzer/generic.nix
+++ b/pkgs/development/tools/rust/rust-analyzer/generic.nix
@@ -16,6 +16,11 @@ rustPlatform.buildRustPackage {
     inherit rev sha256;
   };
 
+  # FIXME: Temporary fix for our rust 1.45.0 since rust-analyzer requires 1.46.0
+  cargoPatches = [
+    ./downgrade-smol_str.patch
+  ];
+
   patches = [
     # FIXME: Temporary fix for our rust 1.45.0 since rust-analyzer requires 1.46.0
     ./no-loop-in-const-fn.patch