12 files changed, 378 insertions, 415 deletions
diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs
index f839616ce..c294a803b 100644
--- a/crates/hir/src/diagnostics.rs
+++ b/crates/hir/src/diagnostics.rs
@@ -37,8 +37,11 @@ diagnostics![
    MacroError,
    MismatchedArgCount,
    MissingFields,
+    MissingOkOrSomeInTailExpr,
    MissingUnsafe,
    NoSuchField,
+    RemoveThisSemicolon,
+    ReplaceFilterMapNextWithFindMap,
    UnimplementedBuiltinMacro,
    UnresolvedExternCrate,
    UnresolvedImport,
@@ -119,9 +122,6 @@ pub struct MissingFields {
    pub missed_fields: Vec<Name>,
 }
-// Diagnostic: replace-filter-map-next-with-find-map
-//
-// This diagnostic is triggered when `.filter_map(..).next()` is used, rather than the more concise `.find_map(..)`.
 #[derive(Debug)]
 pub struct ReplaceFilterMapNextWithFindMap {
    pub file: HirFileId,
@@ -129,21 +129,6 @@ pub struct ReplaceFilterMapNextWithFindMap {
    pub next_expr: AstPtr<ast::Expr>,
 }
-impl Diagnostic for ReplaceFilterMapNextWithFindMap {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("replace-filter-map-next-with-find-map")
-    }
-    fn message(&self) -> String {
-        "replace filter_map(..).next() with find_map(..)".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.next_expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
 #[derive(Debug)]
 pub struct MismatchedArgCount {
    pub call_expr: InFile<AstPtr<ast::Expr>>,
@@ -153,63 +138,16 @@ pub struct MismatchedArgCount {
 #[derive(Debug)]
 pub struct RemoveThisSemicolon {
-    pub file: HirFileId,
+    pub expr: InFile<AstPtr<ast::Expr>>,
-    pub expr: AstPtr<ast::Expr>,
-}
-impl Diagnostic for RemoveThisSemicolon {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("remove-this-semicolon")
-    }
-    fn message(&self) -> String {
-        "Remove this semicolon".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
 }
-// Diagnostic: missing-ok-or-some-in-tail-expr
-//
-// This diagnostic is triggered if a block that should return `Result` returns a value not wrapped in `Ok`,
-// or if a block that should return `Option` returns a value not wrapped in `Some`.
-//
-// Example:
-//
-// ```rust
-// fn foo() -> Result<u8, ()> {
-//     10
-// }
-// ```
 #[derive(Debug)]
 pub struct MissingOkOrSomeInTailExpr {
-    pub file: HirFileId,
+    pub expr: InFile<AstPtr<ast::Expr>>,
-    pub expr: AstPtr<ast::Expr>,
    // `Some` or `Ok` depending on whether the return type is Result or Option
    pub required: String,
 }
-impl Diagnostic for MissingOkOrSomeInTailExpr {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-ok-or-some-in-tail-expr")
-    }
-    fn message(&self) -> String {
-        format!("wrap return expression in {}", self.required)
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
 // Diagnostic: missing-match-arm
 //
 // This diagnostic is triggered if `match` block is missing one or more match arms.
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index c1af5f097..b2731b62f 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -1168,10 +1168,13 @@ impl Function {
                }
                BodyValidationDiagnostic::ReplaceFilterMapNextWithFindMap { method_call_expr } => {
                    if let Ok(next_source_ptr) = source_map.expr_syntax(method_call_expr) {
-                        sink.push(ReplaceFilterMapNextWithFindMap {
+                        acc.push(
-                            file: next_source_ptr.file_id,
+                            ReplaceFilterMapNextWithFindMap {
-                            next_expr: next_source_ptr.value,
+                                file: next_source_ptr.file_id,
-                        });
+                                next_expr: next_source_ptr.value,
+                            }
+                            .into(),
+                        );
                    }
                }
                BodyValidationDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
@@ -1184,20 +1187,13 @@ impl Function {
                }
                BodyValidationDiagnostic::RemoveThisSemicolon { expr } => {
                    match source_map.expr_syntax(expr) {
-                        Ok(source_ptr) => sink.push(RemoveThisSemicolon {
+                        Ok(expr) => acc.push(RemoveThisSemicolon { expr }.into()),
-                            file: source_ptr.file_id,
-                            expr: source_ptr.value,
-                        }),
                        Err(SyntheticSyntax) => (),
                    }
                }
                BodyValidationDiagnostic::MissingOkOrSomeInTailExpr { expr, required } => {
                    match source_map.expr_syntax(expr) {
-                        Ok(source_ptr) => sink.push(MissingOkOrSomeInTailExpr {
+                        Ok(expr) => acc.push(MissingOkOrSomeInTailExpr { expr, required }.into()),
-                            file: source_ptr.file_id,
-                            expr: source_ptr.value,
-                            required,
-                        }),
                        Err(SyntheticSyntax) => (),
                    }
                }
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index 4c92d0cf4..814e64ae4 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -9,8 +9,11 @@ mod inactive_code;
 mod macro_error;
 mod mismatched_arg_count;
 mod missing_fields;
+mod missing_ok_or_some_in_tail_expr;
 mod missing_unsafe;
 mod no_such_field;
+mod remove_this_semicolon;
+mod replace_filter_map_next_with_find_map;
 mod unimplemented_builtin_macro;
 mod unresolved_extern_crate;
 mod unresolved_import;
@@ -162,18 +165,9 @@ pub(crate) fn diagnostics(
    }
    let res = RefCell::new(res);
    let sink_builder = DiagnosticSinkBuilder::new()
-        .on::<hir::diagnostics::MissingOkOrSomeInTailExpr, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::RemoveThisSemicolon, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
        .on::<hir::diagnostics::IncorrectCase, _>(|d| {
            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
        })
-        .on::<hir::diagnostics::ReplaceFilterMapNextWithFindMap, _>(|d| {
-            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
-        })
        .on::<UnlinkedFile, _>(|d| {
            // Limit diagnostic to the first few characters in the file. This matches how VS Code
            // renders it with the full span, but on other editors, and is less invasive.
@@ -223,10 +217,13 @@ pub(crate) fn diagnostics(
        let d = match diag {
            AnyDiagnostic::BreakOutsideOfLoop(d) => break_outside_of_loop::break_outside_of_loop(&ctx, &d),
            AnyDiagnostic::MacroError(d) => macro_error::macro_error(&ctx, &d),
+            AnyDiagnostic::MismatchedArgCount(d) => mismatched_arg_count::mismatched_arg_count(&ctx, &d),
            AnyDiagnostic::MissingFields(d) => missing_fields::missing_fields(&ctx, &d),
+            AnyDiagnostic::MissingOkOrSomeInTailExpr(d) => missing_ok_or_some_in_tail_expr::missing_ok_or_some_in_tail_expr(&ctx, &d),
            AnyDiagnostic::MissingUnsafe(d) => missing_unsafe::missing_unsafe(&ctx, &d),
-            AnyDiagnostic::MismatchedArgCount(d) => mismatched_arg_count::mismatched_arg_count(&ctx, &d),
            AnyDiagnostic::NoSuchField(d) => no_such_field::no_such_field(&ctx, &d),
+            AnyDiagnostic::RemoveThisSemicolon(d) => remove_this_semicolon::remove_this_semicolon(&ctx, &d),
+            AnyDiagnostic::ReplaceFilterMapNextWithFindMap(d) => replace_filter_map_next_with_find_map::replace_filter_map_next_with_find_map(&ctx, &d),
            AnyDiagnostic::UnimplementedBuiltinMacro(d) => unimplemented_builtin_macro::unimplemented_builtin_macro(&ctx, &d),
            AnyDiagnostic::UnresolvedExternCrate(d) => unresolved_extern_crate::unresolved_extern_crate(&ctx, &d),
            AnyDiagnostic::UnresolvedImport(d) => unresolved_import::unresolved_import(&ctx, &d),
@@ -253,16 +250,6 @@ pub(crate) fn diagnostics(
    res
 }
-fn diagnostic_with_fix<D: DiagnosticWithFixes>(
-    d: &D,
-    sema: &Semantics<RootDatabase>,
-    resolve: &AssistResolveStrategy,
-) -> Diagnostic {
-    Diagnostic::error(sema.diagnostics_display_range(d.display_source()).range, d.message())
-        .with_fixes(d.fixes(sema, resolve))
-        .with_code(Some(d.code()))
-}
 fn warning_with_fix<D: DiagnosticWithFixes>(
    d: &D,
    sema: &Semantics<RootDatabase>,
@@ -449,39 +436,6 @@ mod tests {
    }
    #[test]
-    fn range_mapping_out_of_macros() {
-        // FIXME: this is very wrong, but somewhat tricky to fix.
-        check_fix(
-            r#"
-fn some() {}
-fn items() {}
-fn here() {}
-macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
-fn main() {
-    let _x = id![Foo { a: $042 }];
-}
-pub struct Foo { pub a: i32, pub b: i32 }
-"#,
-            r#"
-fn some(, b: () ) {}
-fn items() {}
-fn here() {}
-macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
-fn main() {
-    let _x = id![Foo { a: 42 }];
-}
-pub struct Foo { pub a: i32, pub b: i32 }
-"#,
-        );
-    }
-    #[test]
    fn test_check_unnecessary_braces_in_use_statement() {
        check_diagnostics(
            r#"
@@ -717,137 +671,6 @@ mod foo;
        );
    }
-    // Register the required standard library types to make the tests work
-    fn add_filter_map_with_find_next_boilerplate(body: &str) -> String {
-        let prefix = r#"
-        //- /main.rs crate:main deps:core
-        use core::iter::Iterator;
-        use core::option::Option::{self, Some, None};
-        "#;
-        let suffix = r#"
-        //- /core/lib.rs crate:core
-        pub mod option {
-            pub enum Option<T> { Some(T), None }
-        }
-        pub mod iter {
-            pub trait Iterator {
-                type Item;
-                fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
-                fn next(&mut self) -> Option<Self::Item>;
-            }
-            pub struct FilterMap {}
-            impl Iterator for FilterMap {
-                type Item = i32;
-                fn next(&mut self) -> i32 { 7 }
-            }
-        }
-        "#;
-        format!("{}{}{}", prefix, body, suffix)
-    }
-    #[test]
-    fn replace_filter_map_next_with_find_map2() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3].iter().filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
-                      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ replace filter_map(..).next() with find_map(..)
-            }
-        "#,
-        ));
-    }
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None })
-                    .len();
-            }
-            "#,
-        ));
-    }
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None })
-                    .map(|x| x + 2)
-                    .len();
-            }
-            "#,
-        ));
-    }
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None });
-                let n = m.next();
-            }
-            "#,
-        ));
-    }
-    #[test]
-    fn missing_record_pat_field_no_diagnostic_if_not_exhaustive() {
-        check_diagnostics(
-            r"
-struct S { foo: i32, bar: () }
-fn baz(s: S) -> i32 {
-    match s {
-        S { foo, .. } => foo,
-    }
-}
-",
-        )
-    }
-    #[test]
-    fn missing_record_pat_field_box() {
-        check_diagnostics(
-            r"
-struct S { s: Box<u32> }
-fn x(a: S) {
-    let S { box s } = a;
-}
-",
-        )
-    }
-    #[test]
-    fn missing_record_pat_field_ref() {
-        check_diagnostics(
-            r"
-struct S { s: u32 }
-fn x(a: S) {
-    let S { ref s } = a;
-}
-",
-        )
-    }
-    #[test]
-    fn missing_semicolon() {
-        check_diagnostics(
-            r#"
-                fn test() -> i32 { 123; }
-                                 //^^^ Remove this semicolon
-            "#,
-        );
-    }
    #[test]
    fn import_extern_crate_clash_with_inner_item() {
        // This is more of a resolver test, but doesn't really work with the hir_def testsuite.
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index a2e792b3b..e4bd90c3f 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -1,10 +1,6 @@
 //! Provides a way to attach fixes to the diagnostics.
 //! The same module also has all curret custom fixes for the diagnostics implemented.
 mod change_case;
-mod create_field;
-mod remove_semicolon;
-mod replace_with_find_map;
-mod wrap_tail_expr;
 use hir::{diagnostics::Diagnostic, Semantics};
 use ide_assists::AssistResolveStrategy;
diff --git a/crates/ide/src/diagnostics/fixes/create_field.rs b/crates/ide/src/diagnostics/fixes/create_field.rs
deleted file mode 100644
index 8b1378917..000000000
--- a/crates/ide/src/diagnostics/fixes/create_field.rs
+++ /dev/null
@@ -1 +0,0 @@
diff --git a/crates/ide/src/diagnostics/fixes/remove_semicolon.rs b/crates/ide/src/diagnostics/fixes/remove_semicolon.rs
deleted file mode 100644
index f1724d479..000000000
--- a/crates/ide/src/diagnostics/fixes/remove_semicolon.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::RemoveThisSemicolon, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{source_change::SourceChange, RootDatabase};
-use syntax::{ast, AstNode};
-use text_edit::TextEdit;
-use crate::diagnostics::{fix, DiagnosticWithFixes};
-impl DiagnosticWithFixes for RemoveThisSemicolon {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let semicolon = self
-            .expr
-            .to_node(&root)
-            .syntax()
-            .parent()
-            .and_then(ast::ExprStmt::cast)
-            .and_then(|expr| expr.semicolon_token())?
-            .text_range();
-        let edit = TextEdit::delete(semicolon);
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
-        Some(vec![fix("remove_semicolon", "Remove this semicolon", source_change, semicolon)])
-    }
-}
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_fix;
-    #[test]
-    fn remove_semicolon() {
-        check_fix(r#"fn f() -> i32 { 92$0; }"#, r#"fn f() -> i32 { 92 }"#);
-    }
-}
diff --git a/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs b/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs
deleted file mode 100644
index 444bf563b..000000000
--- a/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::ReplaceFilterMapNextWithFindMap, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{source_change::SourceChange, RootDatabase};
-use syntax::{
-    ast::{self, ArgListOwner},
-    AstNode, TextRange,
-};
-use text_edit::TextEdit;
-use crate::diagnostics::{fix, DiagnosticWithFixes};
-impl DiagnosticWithFixes for ReplaceFilterMapNextWithFindMap {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let next_expr = self.next_expr.to_node(&root);
-        let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
-        let filter_map_call = ast::MethodCallExpr::cast(next_call.receiver()?.syntax().clone())?;
-        let filter_map_name_range = filter_map_call.name_ref()?.ident_token()?.text_range();
-        let filter_map_args = filter_map_call.arg_list()?;
-        let range_to_replace =
-            TextRange::new(filter_map_name_range.start(), next_expr.syntax().text_range().end());
-        let replacement = format!("find_map{}", filter_map_args.syntax().text());
-        let trigger_range = next_expr.syntax().text_range();
-        let edit = TextEdit::replace(range_to_replace, replacement);
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
-        Some(vec![fix(
-            "replace_with_find_map",
-            "Replace filter_map(..).next() with find_map()",
-            source_change,
-            trigger_range,
-        )])
-    }
-}
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_fix;
-    #[test]
-    fn replace_with_wind_map() {
-        check_fix(
-            r#"
-//- /main.rs crate:main deps:core
-use core::iter::Iterator;
-use core::option::Option::{self, Some, None};
-fn foo() {
-    let m = [1, 2, 3].iter().$0filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
-}
-//- /core/lib.rs crate:core
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
-pub mod iter {
-    pub trait Iterator {
-        type Item;
-        fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
-        fn next(&mut self) -> Option<Self::Item>;
-    }
-    pub struct FilterMap {}
-    impl Iterator for FilterMap {
-        type Item = i32;
-        fn next(&mut self) -> i32 { 7 }
-    }
-}
-"#,
-            r#"
-use core::iter::Iterator;
-use core::option::Option::{self, Some, None};
-fn foo() {
-    let m = [1, 2, 3].iter().find_map(|x| if *x == 2 { Some (4) } else { None });
-}
-"#,
-        )
-    }
-}
diff --git a/crates/ide/src/diagnostics/missing_fields.rs b/crates/ide/src/diagnostics/missing_fields.rs
index 95cd64956..d01f05041 100644
--- a/crates/ide/src/diagnostics/missing_fields.rs
+++ b/crates/ide/src/diagnostics/missing_fields.rs
@@ -94,6 +94,77 @@ fn baz(s: S) {
    }
    #[test]
+    fn missing_record_pat_field_no_diagnostic_if_not_exhaustive() {
+        check_diagnostics(
+            r"
+struct S { foo: i32, bar: () }
+fn baz(s: S) -> i32 {
+    match s {
+        S { foo, .. } => foo,
+    }
+}
+",
+        )
+    }
+    #[test]
+    fn missing_record_pat_field_box() {
+        check_diagnostics(
+            r"
+struct S { s: Box<u32> }
+fn x(a: S) {
+    let S { box s } = a;
+}
+",
+        )
+    }
+    #[test]
+    fn missing_record_pat_field_ref() {
+        check_diagnostics(
+            r"
+struct S { s: u32 }
+fn x(a: S) {
+    let S { ref s } = a;
+}
+",
+        )
+    }
+    #[test]
+    fn range_mapping_out_of_macros() {
+        // FIXME: this is very wrong, but somewhat tricky to fix.
+        check_fix(
+            r#"
+fn some() {}
+fn items() {}
+fn here() {}
+macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
+fn main() {
+    let _x = id![Foo { a: $042 }];
+}
+pub struct Foo { pub a: i32, pub b: i32 }
+"#,
+            r#"
+fn some(, b: () ) {}
+fn items() {}
+fn here() {}
+macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
+fn main() {
+    let _x = id![Foo { a: 42 }];
+}
+pub struct Foo { pub a: i32, pub b: i32 }
+"#,
+        );
+    }
+    #[test]
    fn test_fill_struct_fields_empty() {
        check_fix(
            r#"
diff --git a/crates/ide/src/diagnostics/fixes/wrap_tail_expr.rs b/crates/ide/src/diagnostics/missing_ok_or_some_in_tail_expr.rs
index dcb21e037..06005d156 100644
--- a/crates/ide/src/diagnostics/fixes/wrap_tail_expr.rs
+++ b/crates/ide/src/diagnostics/missing_ok_or_some_in_tail_expr.rs
@@ -1,26 +1,45 @@
-use hir::{db::AstDatabase, diagnostics::MissingOkOrSomeInTailExpr, Semantics};
+use hir::db::AstDatabase;
-use ide_assists::{Assist, AssistResolveStrategy};
+use ide_assists::Assist;
-use ide_db::{source_change::SourceChange, RootDatabase};
+use ide_db::source_change::SourceChange;
 use syntax::AstNode;
 use text_edit::TextEdit;
-use crate::diagnostics::{fix, DiagnosticWithFixes};
+use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
-impl DiagnosticWithFixes for MissingOkOrSomeInTailExpr {
+// Diagnostic: missing-ok-or-some-in-tail-expr
-    fn fixes(
+//
-        &self,
+// This diagnostic is triggered if a block that should return `Result` returns a value not wrapped in `Ok`,
-        sema: &Semantics<RootDatabase>,
+// or if a block that should return `Option` returns a value not wrapped in `Some`.
-        _resolve: &AssistResolveStrategy,
+//
-    ) -> Option<Vec<Assist>> {
+// Example:
-        let root = sema.db.parse_or_expand(self.file)?;
+//
-        let tail_expr = self.expr.to_node(&root);
+// ```rust
-        let tail_expr_range = tail_expr.syntax().text_range();
+// fn foo() -> Result<u8, ()> {
-        let replacement = format!("{}({})", self.required, tail_expr.syntax());
+//     10
-        let edit = TextEdit::replace(tail_expr_range, replacement);
+// }
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
+// ```
-        let name = if self.required == "Ok" { "Wrap with Ok" } else { "Wrap with Some" };
+pub(super) fn missing_ok_or_some_in_tail_expr(
-        Some(vec![fix("wrap_tail_expr", name, source_change, tail_expr_range)])
+    ctx: &DiagnosticsContext<'_>,
-    }
+    d: &hir::MissingOkOrSomeInTailExpr,
+) -> Diagnostic {
+    Diagnostic::new(
+        "missing-ok-or-some-in-tail-expr",
+        format!("wrap return expression in {}", d.required),
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingOkOrSomeInTailExpr) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
+    let tail_expr = d.expr.value.to_node(&root);
+    let tail_expr_range = tail_expr.syntax().text_range();
+    let replacement = format!("{}({})", d.required, tail_expr.syntax());
+    let edit = TextEdit::replace(tail_expr_range, replacement);
+    let source_change =
+        SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
+    let name = if d.required == "Ok" { "Wrap with Ok" } else { "Wrap with Some" };
+    Some(vec![fix("wrap_tail_expr", name, source_change, tail_expr_range)])
 }
 #[cfg(test)]
diff --git a/crates/ide/src/diagnostics/no_such_field.rs b/crates/ide/src/diagnostics/no_such_field.rs
index 61962de28..edc63c246 100644
--- a/crates/ide/src/diagnostics/no_such_field.rs
+++ b/crates/ide/src/diagnostics/no_such_field.rs
@@ -17,7 +17,7 @@ use crate::{
 pub(super) fn no_such_field(ctx: &DiagnosticsContext<'_>, d: &hir::NoSuchField) -> Diagnostic {
    Diagnostic::new(
        "no-such-field",
-        "no such field".to_string(),
+        "no such field",
        ctx.sema.diagnostics_display_range(d.field.clone().map(|it| it.into())).range,
    )
    .with_fixes(fixes(ctx, d))
diff --git a/crates/ide/src/diagnostics/remove_this_semicolon.rs b/crates/ide/src/diagnostics/remove_this_semicolon.rs
new file mode 100644
index 000000000..814cb0f8c
--- /dev/null
+++ b/crates/ide/src/diagnostics/remove_this_semicolon.rs
@@ -0,0 +1,64 @@
+use hir::db::AstDatabase;
+use ide_db::source_change::SourceChange;
+use syntax::{ast, AstNode};
+use text_edit::TextEdit;
+use crate::{
+    diagnostics::{fix, Diagnostic, DiagnosticsContext},
+    Assist,
+};
+// Diagnostic: remove-this-semicolon
+//
+// This diagnostic is triggered when there's an erroneous `;` at the end of the block.
+pub(super) fn remove_this_semicolon(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::RemoveThisSemicolon,
+) -> Diagnostic {
+    Diagnostic::new(
+        "remove-this-semicolon",
+        "remove this semicolon",
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::RemoveThisSemicolon) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
+    let semicolon = d
+        .expr
+        .value
+        .to_node(&root)
+        .syntax()
+        .parent()
+        .and_then(ast::ExprStmt::cast)
+        .and_then(|expr| expr.semicolon_token())?
+        .text_range();
+    let edit = TextEdit::delete(semicolon);
+    let source_change =
+        SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
+    Some(vec![fix("remove_semicolon", "Remove this semicolon", source_change, semicolon)])
+}
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    #[test]
+    fn missing_semicolon() {
+        check_diagnostics(
+            r#"
+fn test() -> i32 { 123; }
+                 //^^^ remove this semicolon
+"#,
+        );
+    }
+    #[test]
+    fn remove_semicolon() {
+        check_fix(r#"fn f() -> i32 { 92$0; }"#, r#"fn f() -> i32 { 92 }"#);
+    }
+}
diff --git a/crates/ide/src/diagnostics/replace_filter_map_next_with_find_map.rs b/crates/ide/src/diagnostics/replace_filter_map_next_with_find_map.rs
new file mode 100644
index 000000000..f3b011495
--- /dev/null
+++ b/crates/ide/src/diagnostics/replace_filter_map_next_with_find_map.rs
@@ -0,0 +1,182 @@
+use hir::{db::AstDatabase, InFile};
+use ide_db::source_change::SourceChange;
+use syntax::{
+    ast::{self, ArgListOwner},
+    AstNode, TextRange,
+};
+use text_edit::TextEdit;
+use crate::{
+    diagnostics::{fix, Diagnostic, DiagnosticsContext},
+    Assist, Severity,
+};
+// Diagnostic: replace-filter-map-next-with-find-map
+//
+// This diagnostic is triggered when `.filter_map(..).next()` is used, rather than the more concise `.find_map(..)`.
+pub(super) fn replace_filter_map_next_with_find_map(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::ReplaceFilterMapNextWithFindMap,
+) -> Diagnostic {
+    Diagnostic::new(
+        "replace-filter-map-next-with-find-map",
+        "replace filter_map(..).next() with find_map(..)",
+        ctx.sema.diagnostics_display_range(InFile::new(d.file, d.next_expr.clone().into())).range,
+    )
+    .severity(Severity::WeakWarning)
+    .with_fixes(fixes(ctx, d))
+}
+fn fixes(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::ReplaceFilterMapNextWithFindMap,
+) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.file)?;
+    let next_expr = d.next_expr.to_node(&root);
+    let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
+    let filter_map_call = ast::MethodCallExpr::cast(next_call.receiver()?.syntax().clone())?;
+    let filter_map_name_range = filter_map_call.name_ref()?.ident_token()?.text_range();
+    let filter_map_args = filter_map_call.arg_list()?;
+    let range_to_replace =
+        TextRange::new(filter_map_name_range.start(), next_expr.syntax().text_range().end());
+    let replacement = format!("find_map{}", filter_map_args.syntax().text());
+    let trigger_range = next_expr.syntax().text_range();
+    let edit = TextEdit::replace(range_to_replace, replacement);
+    let source_change = SourceChange::from_text_edit(d.file.original_file(ctx.sema.db), edit);
+    Some(vec![fix(
+        "replace_with_find_map",
+        "Replace filter_map(..).next() with find_map()",
+        source_change,
+        trigger_range,
+    )])
+}
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::check_fix;
+    // Register the required standard library types to make the tests work
+    #[track_caller]
+    fn check_diagnostics(ra_fixture: &str) {
+        let prefix = r#"
+//- /main.rs crate:main deps:core
+use core::iter::Iterator;
+use core::option::Option::{self, Some, None};
+"#;
+        let suffix = r#"
+//- /core/lib.rs crate:core
+pub mod option {
+    pub enum Option<T> { Some(T), None }
+}
+pub mod iter {
+    pub trait Iterator {
+        type Item;
+        fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
+        fn next(&mut self) -> Option<Self::Item>;
+    }
+    pub struct FilterMap {}
+    impl Iterator for FilterMap {
+        type Item = i32;
+        fn next(&mut self) -> i32 { 7 }
+    }
+}
+"#;
+        crate::diagnostics::tests::check_diagnostics(&format!("{}{}{}", prefix, ra_fixture, suffix))
+    }
+    #[test]
+    fn replace_filter_map_next_with_find_map2() {
+        check_diagnostics(
+            r#"
+    fn foo() {
+        let m = [1, 2, 3].iter().filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
+    }         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ replace filter_map(..).next() with find_map(..)
+"#,
+        );
+    }
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| if *x == 2 { Some (4) } else { None })
+        .len();
+}
+"#,
+        );
+    }
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| if *x == 2 { Some (4) } else { None })
+        .map(|x| x + 2)
+        .len();
+}
+"#,
+        );
+    }
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| if *x == 2 { Some (4) } else { None });
+    let n = m.next();
+}
+"#,
+        );
+    }
+    #[test]
+    fn replace_with_wind_map() {
+        check_fix(
+            r#"
+//- /main.rs crate:main deps:core
+use core::iter::Iterator;
+use core::option::Option::{self, Some, None};
+fn foo() {
+    let m = [1, 2, 3].iter().$0filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
+}
+//- /core/lib.rs crate:core
+pub mod option {
+    pub enum Option<T> { Some(T), None }
+}
+pub mod iter {
+    pub trait Iterator {
+        type Item;
+        fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
+        fn next(&mut self) -> Option<Self::Item>;
+    }
+    pub struct FilterMap {}
+    impl Iterator for FilterMap {
+        type Item = i32;
+        fn next(&mut self) -> i32 { 7 }
+    }
+}
+"#,
+            r#"
+use core::iter::Iterator;
+use core::option::Option::{self, Some, None};
+fn foo() {
+    let m = [1, 2, 3].iter().find_map(|x| if *x == 2 { Some (4) } else { None });
+}
+"#,
+        )
+    }
+}