13 files changed, 456 insertions, 56 deletions
diff --git a/crates/ra_ide/src/completion/complete_dot.rs b/crates/ra_ide/src/completion/complete_dot.rs
index 814354ffa..05f825c6f 100644
--- a/crates/ra_ide/src/completion/complete_dot.rs
+++ b/crates/ra_ide/src/completion/complete_dot.rs
@@ -250,6 +250,44 @@ mod tests {
    }
    #[test]
+    fn test_union_field_completion() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+            union Un {
+                field: u8,
+                other: u16,
+            }
+            fn foo(u: Un) {
+                u.<|>
+            }
+            ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "field",
+                source_range: 140..140,
+                delete: 140..140,
+                insert: "field",
+                kind: Field,
+                detail: "u8",
+            },
+            CompletionItem {
+                label: "other",
+                source_range: 140..140,
+                delete: 140..140,
+                insert: "other",
+                kind: Field,
+                detail: "u16",
+            },
+        ]
+        "###
+        );
+    }
+    #[test]
    fn test_method_completion() {
        assert_debug_snapshot!(
        do_ref_completion(
diff --git a/crates/ra_ide/src/completion/complete_qualified_path.rs b/crates/ra_ide/src/completion/complete_qualified_path.rs
index dd10f74e6..aa56a5cd8 100644
--- a/crates/ra_ide/src/completion/complete_qualified_path.rs
+++ b/crates/ra_ide/src/completion/complete_qualified_path.rs
@@ -5,19 +5,29 @@ use ra_syntax::AstNode;
 use test_utils::tested_by;
 use crate::completion::{CompletionContext, Completions};
+use rustc_hash::FxHashSet;
 pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionContext) {
    let path = match &ctx.path_prefix {
        Some(path) => path.clone(),
        _ => return,
    };
-    let def = match ctx.scope().resolve_hir_path(&path) {
+    let scope = ctx.scope();
-        Some(PathResolution::Def(def)) => def,
+    let context_module = scope.module();
-        _ => return,
+    let res = match scope.resolve_hir_path(&path) {
+        Some(res) => res,
+        None => return,
    };
-    let context_module = ctx.scope().module();
-    match def {
+    // Add associated types on type parameters and `Self`.
-        hir::ModuleDef::Module(module) => {
+    res.assoc_type_shorthand_candidates(ctx.db, |alias| {
+        acc.add_type_alias(ctx, alias);
+        None::<()>
+    });
+    match res {
+        PathResolution::Def(hir::ModuleDef::Module(module)) => {
            let module_scope = module.scope(ctx.db, context_module);
            for (name, def) in module_scope {
                if ctx.use_item_syntax.is_some() {
@@ -35,7 +45,8 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                acc.add_resolution(ctx, name.to_string(), &def);
            }
        }
-        hir::ModuleDef::Adt(_) | hir::ModuleDef::TypeAlias(_) => {
+        PathResolution::Def(def @ hir::ModuleDef::Adt(_))
+        | PathResolution::Def(def @ hir::ModuleDef::TypeAlias(_)) => {
            if let hir::ModuleDef::Adt(Adt::Enum(e)) = def {
                for variant in e.variants(ctx.db) {
                    acc.add_enum_variant(ctx, variant, None);
@@ -46,8 +57,10 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                hir::ModuleDef::TypeAlias(a) => a.ty(ctx.db),
                _ => unreachable!(),
            };
-            // Iterate assoc types separately
-            // FIXME: complete T::AssocType
+            // XXX: For parity with Rust bug #22519, this does not complete Ty::AssocType.
+            // (where AssocType is defined on a trait, not an inherent impl)
            let krate = ctx.krate;
            if let Some(krate) = krate {
                let traits_in_scope = ctx.scope().traits_in_scope();
@@ -65,6 +78,7 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                    None::<()>
                });
+                // Iterate assoc types separately
                ty.iterate_impl_items(ctx.db, krate, |item| {
                    if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
                        return None;
@@ -77,7 +91,8 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                });
            }
        }
-        hir::ModuleDef::Trait(t) => {
+        PathResolution::Def(hir::ModuleDef::Trait(t)) => {
+            // Handles `Trait::assoc` as well as `<Ty as Trait>::assoc`.
            for item in t.items(ctx.db) {
                if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
                    continue;
@@ -91,8 +106,38 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                }
            }
        }
+        PathResolution::TypeParam(_) | PathResolution::SelfType(_) => {
+            if let Some(krate) = ctx.krate {
+                let ty = match res {
+                    PathResolution::TypeParam(param) => param.ty(ctx.db),
+                    PathResolution::SelfType(impl_def) => impl_def.target_ty(ctx.db),
+                    _ => return,
+                };
+                let traits_in_scope = ctx.scope().traits_in_scope();
+                let mut seen = FxHashSet::default();
+                ty.iterate_path_candidates(ctx.db, krate, &traits_in_scope, None, |_ty, item| {
+                    if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
+                        return None;
+                    }
+                    // We might iterate candidates of a trait multiple times here, so deduplicate
+                    // them.
+                    if seen.insert(item) {
+                        match item {
+                            hir::AssocItem::Function(func) => {
+                                acc.add_function(ctx, func, None);
+                            }
+                            hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
+                            hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
+                        }
+                    }
+                    None::<()>
+                });
+            }
+        }
        _ => {}
-    };
+    }
 }
 #[cfg(test)]
@@ -844,6 +889,211 @@ mod tests {
    }
    #[test]
+    fn completes_ty_param_assoc_ty() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                "
+                //- /lib.rs
+                trait Super {
+                    type Ty;
+                    const CONST: u8;
+                    fn func() {}
+                    fn method(&self) {}
+                }
+                trait Sub: Super {
+                    type SubTy;
+                    const C2: ();
+                    fn subfunc() {}
+                    fn submethod(&self) {}
+                }
+                fn foo<T: Sub>() {
+                    T::<|>
+                }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "C2",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "C2",
+                kind: Const,
+                detail: "const C2: ();",
+            },
+            CompletionItem {
+                label: "CONST",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "CONST",
+                kind: Const,
+                detail: "const CONST: u8;",
+            },
+            CompletionItem {
+                label: "SubTy",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "SubTy",
+                kind: TypeAlias,
+                detail: "type SubTy;",
+            },
+            CompletionItem {
+                label: "Ty",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "Ty",
+                kind: TypeAlias,
+                detail: "type Ty;",
+            },
+            CompletionItem {
+                label: "func()",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "func()$0",
+                kind: Function,
+                lookup: "func",
+                detail: "fn func()",
+            },
+            CompletionItem {
+                label: "method()",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "method()$0",
+                kind: Method,
+                lookup: "method",
+                detail: "fn method(&self)",
+            },
+            CompletionItem {
+                label: "subfunc()",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "subfunc()$0",
+                kind: Function,
+                lookup: "subfunc",
+                detail: "fn subfunc()",
+            },
+            CompletionItem {
+                label: "submethod()",
+                source_range: 219..219,
+                delete: 219..219,
+                insert: "submethod()$0",
+                kind: Method,
+                lookup: "submethod",
+                detail: "fn submethod(&self)",
+            },
+        ]
+        "###
+        );
+    }
+    #[test]
+    fn completes_self_param_assoc_ty() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                "
+                //- /lib.rs
+                trait Super {
+                    type Ty;
+                    const CONST: u8 = 0;
+                    fn func() {}
+                    fn method(&self) {}
+                }
+                trait Sub: Super {
+                    type SubTy;
+                    const C2: () = ();
+                    fn subfunc() {}
+                    fn submethod(&self) {}
+                }
+                struct Wrap<T>(T);
+                impl<T> Super for Wrap<T> {}
+                impl<T> Sub for Wrap<T> {
+                    fn subfunc() {
+                        // Should be able to assume `Self: Sub + Super`
+                        Self::<|>
+                    }
+                }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "C2",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "C2",
+                kind: Const,
+                detail: "const C2: () = ();",
+            },
+            CompletionItem {
+                label: "CONST",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "CONST",
+                kind: Const,
+                detail: "const CONST: u8 = 0;",
+            },
+            CompletionItem {
+                label: "SubTy",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "SubTy",
+                kind: TypeAlias,
+                detail: "type SubTy;",
+            },
+            CompletionItem {
+                label: "Ty",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "Ty",
+                kind: TypeAlias,
+                detail: "type Ty;",
+            },
+            CompletionItem {
+                label: "func()",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "func()$0",
+                kind: Function,
+                lookup: "func",
+                detail: "fn func()",
+            },
+            CompletionItem {
+                label: "method()",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "method()$0",
+                kind: Method,
+                lookup: "method",
+                detail: "fn method(&self)",
+            },
+            CompletionItem {
+                label: "subfunc()",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "subfunc()$0",
+                kind: Function,
+                lookup: "subfunc",
+                detail: "fn subfunc()",
+            },
+            CompletionItem {
+                label: "submethod()",
+                source_range: 365..365,
+                delete: 365..365,
+                insert: "submethod()$0",
+                kind: Method,
+                lookup: "submethod",
+                detail: "fn submethod(&self)",
+            },
+        ]
+        "###
+        );
+    }
+    #[test]
    fn completes_type_alias() {
        assert_debug_snapshot!(
            do_reference_completion(
diff --git a/crates/ra_ide/src/completion/complete_unqualified_path.rs b/crates/ra_ide/src/completion/complete_unqualified_path.rs
index f559f2b97..a6a5568de 100644
--- a/crates/ra_ide/src/completion/complete_unqualified_path.rs
+++ b/crates/ra_ide/src/completion/complete_unqualified_path.rs
@@ -53,7 +53,7 @@ fn complete_enum_variants(acc: &mut Completions, ctx: &CompletionContext, ty: &T
                // Variants with trivial paths are already added by the existing completion logic,
                // so we should avoid adding these twice
                if path.segments.len() > 1 {
-                    acc.add_enum_variant(ctx, variant, Some(path.to_string()));
+                    acc.add_qualified_enum_variant(ctx, variant, path);
                }
            }
        }
@@ -1173,6 +1173,7 @@ mod tests {
                delete: 248..250,
                insert: "Foo::Bar",
                kind: EnumVariant,
+                lookup: "Bar",
                detail: "()",
            },
            CompletionItem {
@@ -1181,6 +1182,7 @@ mod tests {
                delete: 248..250,
                insert: "Foo::Baz",
                kind: EnumVariant,
+                lookup: "Baz",
                detail: "()",
            },
            CompletionItem {
@@ -1189,6 +1191,7 @@ mod tests {
                delete: 248..250,
                insert: "Foo::Quux",
                kind: EnumVariant,
+                lookup: "Quux",
                detail: "()",
            },
        ]
@@ -1231,6 +1234,7 @@ mod tests {
                delete: 219..221,
                insert: "Foo::Bar",
                kind: EnumVariant,
+                lookup: "Bar",
                detail: "()",
            },
            CompletionItem {
@@ -1239,6 +1243,7 @@ mod tests {
                delete: 219..221,
                insert: "Foo::Baz",
                kind: EnumVariant,
+                lookup: "Baz",
                detail: "()",
            },
            CompletionItem {
@@ -1247,6 +1252,7 @@ mod tests {
                delete: 219..221,
                insert: "Foo::Quux",
                kind: EnumVariant,
+                lookup: "Quux",
                detail: "()",
            },
        ]
@@ -1285,6 +1291,7 @@ mod tests {
                delete: 185..186,
                insert: "Foo::Bar",
                kind: EnumVariant,
+                lookup: "Bar",
                detail: "()",
            },
            CompletionItem {
@@ -1293,6 +1300,7 @@ mod tests {
                delete: 185..186,
                insert: "Foo::Baz",
                kind: EnumVariant,
+                lookup: "Baz",
                detail: "()",
            },
            CompletionItem {
@@ -1301,6 +1309,7 @@ mod tests {
                delete: 185..186,
                insert: "Foo::Quux",
                kind: EnumVariant,
+                lookup: "Quux",
                detail: "()",
            },
            CompletionItem {
@@ -1353,6 +1362,7 @@ mod tests {
                delete: 98..99,
                insert: "m::E::V",
                kind: EnumVariant,
+                lookup: "V",
                detail: "()",
            },
        ]
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 77d354376..2edb130cf 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -1,6 +1,6 @@
 //! This modules takes care of rendering various definitions as completion items.
-use hir::{Docs, HasAttrs, HasSource, HirDisplay, ScopeDef, StructKind, Type};
+use hir::{Docs, HasAttrs, HasSource, HirDisplay, ModPath, ScopeDef, StructKind, Type};
 use ra_syntax::ast::NameOwner;
 use stdx::SepBy;
 use test_utils::tested_by;
@@ -246,14 +246,37 @@ impl Completions {
            .add_to(self);
    }
+    pub(crate) fn add_qualified_enum_variant(
+        &mut self,
+        ctx: &CompletionContext,
+        variant: hir::EnumVariant,
+        path: ModPath,
+    ) {
+        self.add_enum_variant_impl(ctx, variant, None, Some(path))
+    }
    pub(crate) fn add_enum_variant(
        &mut self,
        ctx: &CompletionContext,
        variant: hir::EnumVariant,
        local_name: Option<String>,
    ) {
+        self.add_enum_variant_impl(ctx, variant, local_name, None)
+    }
+    fn add_enum_variant_impl(
+        &mut self,
+        ctx: &CompletionContext,
+        variant: hir::EnumVariant,
+        local_name: Option<String>,
+        path: Option<ModPath>,
+    ) {
        let is_deprecated = is_deprecated(variant, ctx.db);
        let name = local_name.unwrap_or_else(|| variant.name(ctx.db).to_string());
+        let qualified_name = match &path {
+            Some(it) => it.to_string(),
+            None => name.to_string(),
+        };
        let detail_types = variant
            .fields(ctx.db)
            .into_iter()
@@ -271,16 +294,23 @@ impl Completions {
                .surround_with("{ ", " }")
                .to_string(),
        };
-        let mut res =
+        let mut res = CompletionItem::new(
-            CompletionItem::new(CompletionKind::Reference, ctx.source_range(), name.clone())
+            CompletionKind::Reference,
-                .kind(CompletionItemKind::EnumVariant)
+            ctx.source_range(),
-                .set_documentation(variant.docs(ctx.db))
+            qualified_name.clone(),
-                .set_deprecated(is_deprecated)
+        )
-                .detail(detail);
+        .kind(CompletionItemKind::EnumVariant)
+        .set_documentation(variant.docs(ctx.db))
+        .set_deprecated(is_deprecated)
+        .detail(detail);
+        if path.is_some() {
+            res = res.lookup_by(name);
+        }
        if variant_kind == StructKind::Tuple {
            let params = Params::Anonymous(variant.fields(ctx.db).len());
-            res = res.add_call_parens(ctx, name, params)
+            res = res.add_call_parens(ctx, qualified_name, params)
        }
        res.add_to(self);
diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index b5e2785fe..db3907fe6 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -26,6 +26,8 @@ pub struct FunctionSignature {
    pub kind: CallableKind,
    /// Optional visibility
    pub visibility: Option<String>,
+    /// Qualifiers like `async`, `unsafe`, ...
+    pub qualifier: FunctionQualifier,
    /// Name of the function
    pub name: Option<String>,
    /// Documentation for the function
@@ -46,6 +48,16 @@ pub struct FunctionSignature {
    pub has_self_param: bool,
 }
+#[derive(Debug, Default)]
+pub struct FunctionQualifier {
+    // `async` and `const` are mutually exclusive. Do we need to enforcing it here?
+    pub is_async: bool,
+    pub is_const: bool,
+    pub is_unsafe: bool,
+    /// The string `extern ".."`
+    pub extern_abi: Option<String>,
+}
 impl FunctionSignature {
    pub(crate) fn with_doc_opt(mut self, doc: Option<Documentation>) -> Self {
        self.doc = doc;
@@ -83,6 +95,8 @@ impl FunctionSignature {
            FunctionSignature {
                kind: CallableKind::StructConstructor,
                visibility: node.visibility().map(|n| n.syntax().text().to_string()),
+                // Do we need `const`?
+                qualifier: Default::default(),
                name: node.name().map(|n| n.text().to_string()),
                ret_type: node.name().map(|n| n.text().to_string()),
                parameters: params,
@@ -128,6 +142,8 @@ impl FunctionSignature {
            FunctionSignature {
                kind: CallableKind::VariantConstructor,
                visibility: None,
+                // Do we need `const`?
+                qualifier: Default::default(),
                name: Some(name),
                ret_type: None,
                parameters: params,
@@ -151,6 +167,7 @@ impl FunctionSignature {
            FunctionSignature {
                kind: CallableKind::Macro,
                visibility: None,
+                qualifier: Default::default(),
                name: node.name().map(|n| n.text().to_string()),
                ret_type: None,
                parameters: params,
@@ -223,6 +240,12 @@ impl From<&'_ ast::FnDef> for FunctionSignature {
        FunctionSignature {
            kind: CallableKind::Function,
            visibility: node.visibility().map(|n| n.syntax().text().to_string()),
+            qualifier: FunctionQualifier {
+                is_async: node.async_token().is_some(),
+                is_const: node.const_token().is_some(),
+                is_unsafe: node.unsafe_token().is_some(),
+                extern_abi: node.abi().map(|n| n.to_string()),
+            },
            name: node.name().map(|n| n.text().to_string()),
            ret_type: node
                .ret_type()
@@ -246,6 +269,23 @@ impl Display for FunctionSignature {
            write!(f, "{} ", t)?;
        }
+        if self.qualifier.is_async {
+            write!(f, "async ")?;
+        }
+        if self.qualifier.is_const {
+            write!(f, "const ")?;
+        }
+        if self.qualifier.is_unsafe {
+            write!(f, "unsafe ")?;
+        }
+        if let Some(extern_abi) = &self.qualifier.extern_abi {
+            // Keyword `extern` is included in the string.
+            write!(f, "{} ", extern_abi)?;
+        }
        if let Some(name) = &self.name {
            match self.kind {
                CallableKind::Function => write!(f, "fn {}", name)?,
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index 58c799eca..a62f598f0 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -844,4 +844,29 @@ fn func(foo: i32) { if true { <|>foo; }; }
            &["fn foo()\n```\n\n<- `\u{3000}` here"],
        );
    }
+    #[test]
+    fn test_hover_function_show_qualifiers() {
+        check_hover_result(
+            "
+            //- /lib.rs
+            async fn foo<|>() {}
+            ",
+            &["async fn foo()"],
+        );
+        check_hover_result(
+            "
+            //- /lib.rs
+            pub const unsafe fn foo<|>() {}
+            ",
+            &["pub const unsafe fn foo()"],
+        );
+        check_hover_result(
+            r#"
+            //- /lib.rs
+            pub(crate) async unsafe extern "C" fn foo<|>() {}
+            "#,
+            &[r#"pub(crate) async unsafe extern "C" fn foo()"#],
+        );
+    }
 }
diff --git a/crates/ra_ide/src/snapshots/highlight_injection.html b/crates/ra_ide/src/snapshots/highlight_injection.html
index 6ec13bd80..ea026d7a0 100644
--- a/crates/ra_ide/src/snapshots/highlight_injection.html
+++ b/crates/ra_ide/src/snapshots/highlight_injection.html
@@ -20,6 +20,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .macro              { color: #94BFF3; }
 .module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
 .keyword            { color: #F0DFAF; font-weight: bold; }
diff --git a/crates/ra_ide/src/snapshots/highlight_strings.html b/crates/ra_ide/src/snapshots/highlight_strings.html
index 433f2e0c5..de06daf72 100644
--- a/crates/ra_ide/src/snapshots/highlight_strings.html
+++ b/crates/ra_ide/src/snapshots/highlight_strings.html
@@ -20,6 +20,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .macro              { color: #94BFF3; }
 .module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
 .keyword            { color: #F0DFAF; font-weight: bold; }
@@ -40,43 +41,43 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 <span class="keyword">fn</span> <span class="function declaration">main</span>() {
    <span class="comment">// from https://doc.rust-lang.org/std/fmt/index.html</span>
    <span class="macro">println!</span>(<span class="string_literal">"Hello"</span>);                 <span class="comment">// =&gt; "Hello"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"Hello, </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"world"</span>);   <span class="comment">// =&gt; "Hello, world!"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"Hello, </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"world"</span>);   <span class="comment">// =&gt; "Hello, world!"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"The number is </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>);   <span class="comment">// =&gt; "The number is 1"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"The number is </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>);   <span class="comment">// =&gt; "The number is 1"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">?</span><span class="attribute">}</span><span class="string_literal">"</span>, (<span class="numeric_literal">3</span>, <span class="numeric_literal">4</span>));          <span class="comment">// =&gt; "(3, 4)"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">?</span><span class="format_specifier">}</span><span class="string_literal">"</span>, (<span class="numeric_literal">3</span>, <span class="numeric_literal">4</span>));          <span class="comment">// =&gt; "(3, 4)"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">value</span><span class="attribute">}</span><span class="string_literal">"</span>, value=<span class="numeric_literal">4</span>);      <span class="comment">// =&gt; "4"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">value</span><span class="format_specifier">}</span><span class="string_literal">"</span>, value=<span class="numeric_literal">4</span>);      <span class="comment">// =&gt; "4"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, <span class="numeric_literal">2</span>);           <span class="comment">// =&gt; "1 2"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, <span class="numeric_literal">2</span>);           <span class="comment">// =&gt; "1 2"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">:</span><span class="numeric_literal">0</span><span class="numeric_literal">4</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">42</span>);             <span class="comment">// =&gt; "0042" with leading zerosV</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="numeric_literal">0</span><span class="numeric_literal">4</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">42</span>);             <span class="comment">// =&gt; "0042" with leading zerosV</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="numeric_literal">1</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="numeric_literal">0</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, <span class="numeric_literal">2</span>);   <span class="comment">// =&gt; "2 1 1 2"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="numeric_literal">1</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="numeric_literal">0</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, <span class="numeric_literal">2</span>);   <span class="comment">// =&gt; "2 1 1 2"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">argument</span><span class="attribute">}</span><span class="string_literal">"</span>, argument = <span class="string_literal">"test"</span>);   <span class="comment">// =&gt; "test"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">argument</span><span class="format_specifier">}</span><span class="string_literal">"</span>, argument = <span class="string_literal">"test"</span>);   <span class="comment">// =&gt; "test"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">name</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, name = <span class="numeric_literal">2</span>);          <span class="comment">// =&gt; "2 1"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">name</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">1</span>, name = <span class="numeric_literal">2</span>);          <span class="comment">// =&gt; "2 1"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">a</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="variable">c</span><span class="attribute">}</span><span class="string_literal"> </span><span class="attribute">{</span><span class="variable">b</span><span class="attribute">}</span><span class="string_literal">"</span>, a=<span class="string_literal">"a"</span>, b=<span class="char_literal">'b'</span>, c=<span class="numeric_literal">3</span>);  <span class="comment">// =&gt; "a 3 b"</span>
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">a</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="variable">c</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="variable">b</span><span class="format_specifier">}</span><span class="string_literal">"</span>, a=<span class="string_literal">"a"</span>, b=<span class="char_literal">'b'</span>, c=<span class="numeric_literal">3</span>);  <span class="comment">// =&gt; "a 3 b"</span>
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="numeric_literal">1</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="numeric_literal">1</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="numeric_literal">1</span><span class="attribute">:</span><span class="numeric_literal">0</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="numeric_literal">1</span><span class="format_specifier">:</span><span class="numeric_literal">0</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="variable">width</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>, width = <span class="numeric_literal">5</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="variable">width</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>, width = <span class="numeric_literal">5</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">&lt;</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">&lt;</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">-</span><span class="attribute">&lt;</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">-</span><span class="format_specifier">&lt;</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">^</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">^</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">&gt;</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">&gt;</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"x"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">+</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">+</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">#</span><span class="variable">x</span><span class="string_literal">}!"</span>, <span class="numeric_literal">27</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">#</span><span class="variable">x</span><span class="string_literal">}!"</span>, <span class="numeric_literal">27</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="numeric_literal">0</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="numeric_literal">0</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">5</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">:</span><span class="numeric_literal">0</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">!"</span>, -<span class="numeric_literal">5</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="numeric_literal">0</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, -<span class="numeric_literal">5</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">#</span><span class="numeric_literal">0</span><span class="numeric_literal">10</span><span class="variable">x</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">27</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">#</span><span class="numeric_literal">0</span><span class="numeric_literal">10</span><span class="variable">x</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="numeric_literal">27</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="numeric_literal">0</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="numeric_literal">1</span><span class="attribute">:</span><span class="attribute">.</span><span class="numeric_literal">5</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="numeric_literal">0</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="numeric_literal">1</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="numeric_literal">5</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="numeric_literal">1</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="numeric_literal">2</span><span class="attribute">:</span><span class="attribute">.</span><span class="numeric_literal">0</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="numeric_literal">5</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="numeric_literal">1</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="numeric_literal">2</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="numeric_literal">0</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="numeric_literal">5</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="numeric_literal">0</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="numeric_literal">2</span><span class="attribute">:</span><span class="attribute">.</span><span class="numeric_literal">1</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="numeric_literal">0</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="numeric_literal">2</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="numeric_literal">1</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="attribute">:</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">"</span>,    <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="format_specifier">*</span><span class="format_specifier">}</span><span class="string_literal">"</span>,    <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="numeric_literal">2</span><span class="attribute">:</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">"</span>,   <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="numeric_literal">2</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="format_specifier">*</span><span class="format_specifier">}</span><span class="string_literal">"</span>,   <span class="string_literal">"x"</span>, <span class="numeric_literal">5</span>, <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal"> is </span><span class="attribute">{</span><span class="variable">number</span><span class="attribute">:</span><span class="attribute">.</span><span class="variable">prec</span><span class="attribute">$</span><span class="attribute">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, prec = <span class="numeric_literal">5</span>, number = <span class="numeric_literal">0.01</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"Hello </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> is </span><span class="format_specifier">{</span><span class="variable">number</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="variable">prec</span><span class="format_specifier">$</span><span class="format_specifier">}</span><span class="string_literal">"</span>, <span class="string_literal">"x"</span>, prec = <span class="numeric_literal">5</span>, number = <span class="numeric_literal">0.01</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">, `</span><span class="attribute">{</span><span class="variable">name</span><span class="attribute">:</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">` has 3 fractional digits"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="numeric_literal">1234.56</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">, `</span><span class="format_specifier">{</span><span class="variable">name</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="format_specifier">*</span><span class="format_specifier">}</span><span class="string_literal">` has 3 fractional digits"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="numeric_literal">1234.56</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">, `</span><span class="attribute">{</span><span class="variable">name</span><span class="attribute">:</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">` has 3 characters"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="string_literal">"1234.56"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">, `</span><span class="format_specifier">{</span><span class="variable">name</span><span class="format_specifier">:</span><span class="format_specifier">.</span><span class="format_specifier">*</span><span class="format_specifier">}</span><span class="string_literal">` has 3 characters"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="string_literal">"1234.56"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">, `</span><span class="attribute">{</span><span class="variable">name</span><span class="attribute">:</span><span class="attribute">&gt;</span><span class="numeric_literal">8</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">` has 3 right-aligned characters"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="string_literal">"1234.56"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">, `</span><span class="format_specifier">{</span><span class="variable">name</span><span class="format_specifier">:</span><span class="format_specifier">&gt;</span><span class="numeric_literal">8</span><span class="format_specifier">.</span><span class="format_specifier">*</span><span class="format_specifier">}</span><span class="string_literal">` has 3 right-aligned characters"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="string_literal">"1234.56"</span>);
    <span class="macro">println!</span>(<span class="string_literal">"Hello {{}}"</span>);
    <span class="macro">println!</span>(<span class="string_literal">"{{ Hello"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">r"Hello, </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"world"</span>);
+    <span class="macro">println!</span>(<span class="string_literal">r"Hello, </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal">!"</span>, <span class="string_literal">"world"</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">\x41</span><span class="attribute">}</span><span class="string_literal">"</span>, A = <span class="numeric_literal">92</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">\x41</span><span class="format_specifier">}</span><span class="string_literal">"</span>, A = <span class="numeric_literal">92</span>);
-    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">ничоси</span><span class="attribute">}</span><span class="string_literal">"</span>, ничоси = <span class="numeric_literal">92</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">ничоси</span><span class="format_specifier">}</span><span class="string_literal">"</span>, ничоси = <span class="numeric_literal">92</span>);
 }</code></pre>
 \ No newline at end of file
diff --git a/crates/ra_ide/src/snapshots/highlighting.html b/crates/ra_ide/src/snapshots/highlighting.html
index ccb1fc751..4b12fe823 100644
--- a/crates/ra_ide/src/snapshots/highlighting.html
+++ b/crates/ra_ide/src/snapshots/highlighting.html
@@ -20,6 +20,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .macro              { color: #94BFF3; }
 .module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
 .keyword            { color: #F0DFAF; font-weight: bold; }
diff --git a/crates/ra_ide/src/snapshots/rainbow_highlighting.html b/crates/ra_ide/src/snapshots/rainbow_highlighting.html
index 3df82c45f..11e1f3e44 100644
--- a/crates/ra_ide/src/snapshots/rainbow_highlighting.html
+++ b/crates/ra_ide/src/snapshots/rainbow_highlighting.html
@@ -20,6 +20,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .macro              { color: #94BFF3; }
 .module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
 .keyword            { color: #F0DFAF; font-weight: bold; }
diff --git a/crates/ra_ide/src/syntax_highlighting.rs b/crates/ra_ide/src/syntax_highlighting.rs
index be0f8c827..6658c7bb2 100644
--- a/crates/ra_ide/src/syntax_highlighting.rs
+++ b/crates/ra_ide/src/syntax_highlighting.rs
@@ -290,7 +290,7 @@ fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
        | FormatSpecifier::DollarSign
        | FormatSpecifier::Dot
        | FormatSpecifier::Asterisk
-        | FormatSpecifier::QuestionMark => HighlightTag::Attribute,
+        | FormatSpecifier::QuestionMark => HighlightTag::FormatSpecifier,
        FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral,
        FormatSpecifier::Identifier => HighlightTag::Local,
    })
diff --git a/crates/ra_ide/src/syntax_highlighting/html.rs b/crates/ra_ide/src/syntax_highlighting/html.rs
index 010db4017..ff0eeeb52 100644
--- a/crates/ra_ide/src/syntax_highlighting/html.rs
+++ b/crates/ra_ide/src/syntax_highlighting/html.rs
@@ -79,6 +79,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .macro              { color: #94BFF3; }
 .module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
 .keyword            { color: #F0DFAF; font-weight: bold; }
diff --git a/crates/ra_ide/src/syntax_highlighting/tags.rs b/crates/ra_ide/src/syntax_highlighting/tags.rs
index f2c421654..be1a0f12b 100644
--- a/crates/ra_ide/src/syntax_highlighting/tags.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tags.rs
@@ -39,6 +39,7 @@ pub enum HighlightTag {
    Union,
    Local,
    UnresolvedReference,
+    FormatSpecifier,
 }
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
@@ -81,6 +82,7 @@ impl HighlightTag {
            HighlightTag::Union => "union",
            HighlightTag::Local => "variable",
            HighlightTag::UnresolvedReference => "unresolved_reference",
+            HighlightTag::FormatSpecifier => "format_specifier",
        }
    }
 }