move into_ and as_ generation to a separate file

4 files changed, 340 insertions, 402 deletions

diff --git a/crates/ide_assists/src/handlers/generate_enum_match_method.rs b/crates/ide_assists/src/handlers/generate_enum_match_method.rs
index 670c82200..7e181a480 100644
--- a/crates/ide_assists/src/handlers/generate_enum_match_method.rs
+++ b/crates/ide_assists/src/handlers/generate_enum_match_method.rs
@@ -1,11 +1,9 @@
-use itertools::Itertools;
 use stdx::to_lower_snake_case;
 use syntax::ast::VisibilityOwner;
 use syntax::ast::{self, AstNode, NameOwner};
 
 use crate::{
-    assist_context::AssistBuilder,
-    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
+    utils::{add_method_to_adt, find_struct_impl},
     AssistContext, AssistId, AssistKind, Assists,
 };
 
@@ -39,7 +37,11 @@ pub(crate) fn generate_enum_is_method(acc: &mut Assists, ctx: &AssistContext) ->
     let variant = ctx.find_node_at_offset::<ast::Variant>()?;
     let variant_name = variant.name()?;
     let parent_enum = ast::Adt::Enum(variant.parent_enum());
-    let variant_kind = variant_kind(&variant);
+    let pattern_suffix = match variant.kind() {
+        ast::StructKind::Record(_) => " { .. }",
+        ast::StructKind::Tuple(_) => "(..)",
+        ast::StructKind::Unit => "",
+    };
 
     let enum_lowercase_name = to_lower_snake_case(&parent_enum.name()?.to_string());
     let fn_name = format!("is_{}", &to_lower_snake_case(variant_name.text()));
@@ -59,12 +61,7 @@ pub(crate) fn generate_enum_is_method(acc: &mut Assists, ctx: &AssistContext) ->
     {}fn {}(&self) -> bool {{
         matches!(self, Self::{}{})
     }}",
-                enum_lowercase_name,
-                variant_name,
-                vis,
-                fn_name,
-                variant_name,
-                variant_kind.pattern_suffix(),
+                enum_lowercase_name, variant_name, vis, fn_name, variant_name, pattern_suffix,
             );
 
             add_method_to_adt(builder, &parent_enum, impl_def, &method);
@@ -72,237 +69,6 @@ pub(crate) fn generate_enum_is_method(acc: &mut Assists, ctx: &AssistContext) ->
     )
 }
 
-// Assist: generate_enum_into_method
-//
-// Generate an `into_` method for an enum variant.
-//
-// ```
-// enum Value {
-//  Number(i32),
-//  Text(String)$0,
-// }
-// ```
-// ->
-// ```
-// enum Value {
-//  Number(i32),
-//  Text(String),
-// }
-//
-// impl Value {
-//     fn into_text(self) -> Option<String> {
-//         if let Self::Text(v) = self {
-//             Some(v)
-//         } else {
-//             None
-//         }
-//     }
-// }
-// ```
-pub(crate) fn generate_enum_into_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
-    let variant_name = variant.name()?;
-    let parent_enum = ast::Adt::Enum(variant.parent_enum());
-    let variant_kind = variant_kind(&variant);
-
-    let fn_name = format!("into_{}", &to_lower_snake_case(variant_name.text()));
-
-    // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(&ctx, &parent_enum, &fn_name)?;
-
-    let field_type = variant_kind.single_field_type()?;
-    let (pattern_suffix, bound_name) = variant_kind.binding_pattern()?;
-
-    let target = variant.syntax().text_range();
-    acc.add(
-        AssistId("generate_enum_into_method", AssistKind::Generate),
-        "Generate an `into_` method for an enum variant",
-        target,
-        |builder| {
-            let vis = parent_enum.visibility().map_or(String::new(), |v| format!("{} ", v));
-            let method = format!(
-                "    {}fn {}(self) -> Option<{}> {{
-        if let Self::{}{} = self {{
-            Some({})
-        }} else {{
-            None
-        }}
-    }}",
-                vis,
-                fn_name,
-                field_type.syntax(),
-                variant_name,
-                pattern_suffix,
-                bound_name,
-            );
-
-            add_method_to_adt(builder, &parent_enum, impl_def, &method);
-        },
-    )
-}
-
-// Assist: generate_enum_as_method
-//
-// Generate an `as_` method for an enum variant.
-//
-// ```
-// enum Value {
-//  Number(i32),
-//  Text(String)$0,
-// }
-// ```
-// ->
-// ```
-// enum Value {
-//  Number(i32),
-//  Text(String),
-// }
-//
-// impl Value {
-//     fn as_text(&self) -> Option<&String> {
-//         if let Self::Text(v) = self {
-//             Some(v)
-//         } else {
-//             None
-//         }
-//     }
-// }
-// ```
-pub(crate) fn generate_enum_as_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
-    let variant_name = variant.name()?;
-    let parent_enum = ast::Adt::Enum(variant.parent_enum());
-    let variant_kind = variant_kind(&variant);
-
-    let fn_name = format!("as_{}", &to_lower_snake_case(variant_name.text()));
-
-    // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(&ctx, &parent_enum, &fn_name)?;
-
-    let field_type = variant_kind.single_field_type()?;
-    let (pattern_suffix, bound_name) = variant_kind.binding_pattern()?;
-
-    let target = variant.syntax().text_range();
-    acc.add(
-        AssistId("generate_enum_as_method", AssistKind::Generate),
-        "Generate an `as_` method for an enum variant",
-        target,
-        |builder| {
-            let vis = parent_enum.visibility().map_or(String::new(), |v| format!("{} ", v));
-            let method = format!(
-                "    {}fn {}(&self) -> Option<&{}> {{
-        if let Self::{}{} = self {{
-            Some({})
-        }} else {{
-            None
-        }}
-    }}",
-                vis,
-                fn_name,
-                field_type.syntax(),
-                variant_name,
-                pattern_suffix,
-                bound_name,
-            );
-
-            add_method_to_adt(builder, &parent_enum, impl_def, &method);
-        },
-    )
-}
-
-fn add_method_to_adt(
-    builder: &mut AssistBuilder,
-    adt: &ast::Adt,
-    impl_def: Option<ast::Impl>,
-    method: &str,
-) {
-    let mut buf = String::with_capacity(method.len() + 2);
-    if impl_def.is_some() {
-        buf.push('\n');
-    }
-    buf.push_str(method);
-
-    let start_offset = impl_def
-        .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
-        .unwrap_or_else(|| {
-            buf = generate_impl_text(&adt, &buf);
-            adt.syntax().text_range().end()
-        });
-
-    builder.insert(start_offset, buf);
-}
-
-enum VariantKind {
-    Unit,
-    /// Tuple with a single field
-    NewtypeTuple {
-        ty: Option<ast::Type>,
-    },
-    /// Tuple with 0 or more than 2 fields
-    Tuple,
-    /// Record with a single field
-    NewtypeRecord {
-        field_name: Option<ast::Name>,
-        field_type: Option<ast::Type>,
-    },
-    /// Record with 0 or more than 2 fields
-    Record,
-}
-
-impl VariantKind {
-    fn pattern_suffix(&self) -> &'static str {
-        match self {
-            VariantKind::Unit => "",
-            VariantKind::NewtypeTuple { .. } | VariantKind::Tuple => "(..)",
-            VariantKind::NewtypeRecord { .. } | VariantKind::Record => " { .. }",
-        }
-    }
-
-    fn binding_pattern(&self) -> Option<(String, String)> {
-        match self {
-            VariantKind::Unit
-            | VariantKind::Tuple
-            | VariantKind::Record
-            | VariantKind::NewtypeRecord { field_name: None, .. } => None,
-            VariantKind::NewtypeTuple { .. } => Some(("(v)".to_owned(), "v".to_owned())),
-            VariantKind::NewtypeRecord { field_name: Some(name), .. } => {
-                Some((format!(" {{ {} }}", name.syntax()), name.syntax().to_string()))
-            }
-        }
-    }
-
-    fn single_field_type(&self) -> Option<&ast::Type> {
-        match self {
-            VariantKind::Unit | VariantKind::Tuple | VariantKind::Record => None,
-            VariantKind::NewtypeTuple { ty } => ty.as_ref(),
-            VariantKind::NewtypeRecord { field_type, .. } => field_type.as_ref(),
-        }
-    }
-}
-
-fn variant_kind(variant: &ast::Variant) -> VariantKind {
-    match variant.kind() {
-        ast::StructKind::Record(record) => {
-            if let Some((single_field,)) = record.fields().collect_tuple() {
-                let field_name = single_field.name();
-                let field_type = single_field.ty();
-                VariantKind::NewtypeRecord { field_name, field_type }
-            } else {
-                VariantKind::Record
-            }
-        }
-        ast::StructKind::Tuple(tuple) => {
-            if let Some((single_field,)) = tuple.fields().collect_tuple() {
-                let ty = single_field.ty();
-                VariantKind::NewtypeTuple { ty }
-            } else {
-                VariantKind::Tuple
-            }
-        }
-        ast::StructKind::Unit => VariantKind::Unit,
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
@@ -481,162 +247,4 @@ impl Variant {
 }"#,
         );
     }
-
-    #[test]
-    fn test_generate_enum_into_tuple_variant() {
-        check_assist(
-            generate_enum_into_method,
-            r#"
-enum Value {
-    Number(i32),
-    Text(String)$0,
-}"#,
-            r#"enum Value {
-    Number(i32),
-    Text(String),
-}
-
-impl Value {
-    fn into_text(self) -> Option<String> {
-        if let Self::Text(v) = self {
-            Some(v)
-        } else {
-            None
-        }
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_into_already_implemented() {
-        check_assist_not_applicable(
-            generate_enum_into_method,
-            r#"enum Value {
-    Number(i32),
-    Text(String)$0,
-}
-
-impl Value {
-    fn into_text(self) -> Option<String> {
-        if let Self::Text(v) = self {
-            Some(v)
-        } else {
-            None
-        }
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_into_unit_variant() {
-        check_assist_not_applicable(
-            generate_enum_into_method,
-            r#"enum Value {
-    Number(i32),
-    Text(String),
-    Unit$0,
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_into_record_with_multiple_fields() {
-        check_assist_not_applicable(
-            generate_enum_into_method,
-            r#"enum Value {
-    Number(i32),
-    Text(String),
-    Both { first: i32, second: String }$0,
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_into_tuple_with_multiple_fields() {
-        check_assist_not_applicable(
-            generate_enum_into_method,
-            r#"enum Value {
-    Number(i32),
-    Text(String, String)$0,
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_into_record_variant() {
-        check_assist(
-            generate_enum_into_method,
-            r#"enum Value {
-    Number(i32),
-    Text { text: String }$0,
-}"#,
-            r#"enum Value {
-    Number(i32),
-    Text { text: String },
-}
-
-impl Value {
-    fn into_text(self) -> Option<String> {
-        if let Self::Text { text } = self {
-            Some(text)
-        } else {
-            None
-        }
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_as_tuple_variant() {
-        check_assist(
-            generate_enum_as_method,
-            r#"
-enum Value {
-    Number(i32),
-    Text(String)$0,
-}"#,
-            r#"enum Value {
-    Number(i32),
-    Text(String),
-}
-
-impl Value {
-    fn as_text(&self) -> Option<&String> {
-        if let Self::Text(v) = self {
-            Some(v)
-        } else {
-            None
-        }
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_enum_as_record_variant() {
-        check_assist(
-            generate_enum_as_method,
-            r#"enum Value {
-    Number(i32),
-    Text { text: String }$0,
-}"#,
-            r#"enum Value {
-    Number(i32),
-    Text { text: String },
-}
-
-impl Value {
-    fn as_text(&self) -> Option<&String> {
-        if let Self::Text { text } = self {
-            Some(text)
-        } else {
-            None
-        }
-    }
-}"#,
-        );
-    }
 }
diff --git a/crates/ide_assists/src/handlers/generate_enum_projection_method.rs b/crates/ide_assists/src/handlers/generate_enum_projection_method.rs
new file mode 100644
index 000000000..71447f310
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_enum_projection_method.rs
@@ -0,0 +1,307 @@
+use itertools::Itertools;
+use stdx::to_lower_snake_case;
+use syntax::ast::VisibilityOwner;
+use syntax::ast::{self, AstNode, NameOwner};
+
+use crate::{
+    utils::{add_method_to_adt, find_struct_impl},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_enum_into_method
+//
+// Generate an `into_` method for an enum variant.
+//
+// ```
+// enum Value {
+//  Number(i32),
+//  Text(String)$0,
+// }
+// ```
+// ->
+// ```
+// enum Value {
+//  Number(i32),
+//  Text(String),
+// }
+//
+// impl Value {
+//     fn into_text(self) -> Option<String> {
+//         if let Self::Text(v) = self {
+//             Some(v)
+//         } else {
+//             None
+//         }
+//     }
+// }
+// ```
+pub(crate) fn generate_enum_into_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    generate_enum_projection_method(
+        acc,
+        ctx,
+        "generate_enum_into_method",
+        "Generate an `into_` method for an enum variant",
+        "into",
+        "",
+    )
+}
+
+// Assist: generate_enum_as_method
+//
+// Generate an `as_` method for an enum variant.
+//
+// ```
+// enum Value {
+//  Number(i32),
+//  Text(String)$0,
+// }
+// ```
+// ->
+// ```
+// enum Value {
+//  Number(i32),
+//  Text(String),
+// }
+//
+// impl Value {
+//     fn as_text(&self) -> Option<&String> {
+//         if let Self::Text(v) = self {
+//             Some(v)
+//         } else {
+//             None
+//         }
+//     }
+// }
+// ```
+pub(crate) fn generate_enum_as_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    generate_enum_projection_method(
+        acc,
+        ctx,
+        "generate_enum_as_method",
+        "Generate an `as_` method for an enum variant",
+        "as",
+        "&",
+    )
+}
+
+pub(crate) fn generate_enum_projection_method(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+    assist_id: &'static str,
+    assist_description: &str,
+    fn_name_prefix: &str,
+    ref_prefix: &str,
+) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
+    let variant_name = variant.name()?;
+    let parent_enum = ast::Adt::Enum(variant.parent_enum());
+
+    let (pattern_suffix, field_type, bound_name) = match variant.kind() {
+        ast::StructKind::Record(record) => {
+            let (field,) = record.fields().collect_tuple()?;
+            let name = field.name()?.to_string();
+            let ty = field.ty()?;
+            let pattern_suffix = format!(" {{ {} }}", name);
+            (pattern_suffix, ty, name)
+        }
+        ast::StructKind::Tuple(tuple) => {
+            let (field,) = tuple.fields().collect_tuple()?;
+            let ty = field.ty()?;
+            ("(v)".to_owned(), ty, "v".to_owned())
+        }
+        ast::StructKind::Unit => return None,
+    };
+
+    let fn_name = format!("{}_{}", fn_name_prefix, &to_lower_snake_case(variant_name.text()));
+
+    // Return early if we've found an existing new fn
+    let impl_def = find_struct_impl(&ctx, &parent_enum, &fn_name)?;
+
+    let target = variant.syntax().text_range();
+    acc.add(AssistId(assist_id, AssistKind::Generate), assist_description, target, |builder| {
+        let vis = parent_enum.visibility().map_or(String::new(), |v| format!("{} ", v));
+        let method = format!(
+            "    {0}fn {1}({2}self) -> Option<{2}{3}> {{
+        if let Self::{4}{5} = self {{
+            Some({6})
+        }} else {{
+            None
+        }}
+    }}",
+            vis,
+            fn_name,
+            ref_prefix,
+            field_type.syntax(),
+            variant_name,
+            pattern_suffix,
+            bound_name,
+        );
+
+        add_method_to_adt(builder, &parent_enum, impl_def, &method);
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_generate_enum_into_tuple_variant() {
+        check_assist(
+            generate_enum_into_method,
+            r#"
+enum Value {
+    Number(i32),
+    Text(String)$0,
+}"#,
+            r#"enum Value {
+    Number(i32),
+    Text(String),
+}
+
+impl Value {
+    fn into_text(self) -> Option<String> {
+        if let Self::Text(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_into_already_implemented() {
+        check_assist_not_applicable(
+            generate_enum_into_method,
+            r#"enum Value {
+    Number(i32),
+    Text(String)$0,
+}
+
+impl Value {
+    fn into_text(self) -> Option<String> {
+        if let Self::Text(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_into_unit_variant() {
+        check_assist_not_applicable(
+            generate_enum_into_method,
+            r#"enum Value {
+    Number(i32),
+    Text(String),
+    Unit$0,
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_into_record_with_multiple_fields() {
+        check_assist_not_applicable(
+            generate_enum_into_method,
+            r#"enum Value {
+    Number(i32),
+    Text(String),
+    Both { first: i32, second: String }$0,
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_into_tuple_with_multiple_fields() {
+        check_assist_not_applicable(
+            generate_enum_into_method,
+            r#"enum Value {
+    Number(i32),
+    Text(String, String)$0,
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_into_record_variant() {
+        check_assist(
+            generate_enum_into_method,
+            r#"enum Value {
+    Number(i32),
+    Text { text: String }$0,
+}"#,
+            r#"enum Value {
+    Number(i32),
+    Text { text: String },
+}
+
+impl Value {
+    fn into_text(self) -> Option<String> {
+        if let Self::Text { text } = self {
+            Some(text)
+        } else {
+            None
+        }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_as_tuple_variant() {
+        check_assist(
+            generate_enum_as_method,
+            r#"
+enum Value {
+    Number(i32),
+    Text(String)$0,
+}"#,
+            r#"enum Value {
+    Number(i32),
+    Text(String),
+}
+
+impl Value {
+    fn as_text(&self) -> Option<&String> {
+        if let Self::Text(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_as_record_variant() {
+        check_assist(
+            generate_enum_as_method,
+            r#"enum Value {
+    Number(i32),
+    Text { text: String }$0,
+}"#,
+            r#"enum Value {
+    Number(i32),
+    Text { text: String },
+}
+
+impl Value {
+    fn as_text(&self) -> Option<&String> {
+        if let Self::Text { text } = self {
+            Some(text)
+        } else {
+            None
+        }
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 84ac928e9..4a7cd5848 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -129,6 +129,7 @@ mod handlers {
     mod generate_default_from_enum_variant;
     mod generate_derive;
     mod generate_enum_match_method;
+    mod generate_enum_projection_method;
     mod generate_from_impl_for_enum;
     mod generate_function;
     mod generate_getter;
@@ -190,8 +191,8 @@ mod handlers {
             generate_default_from_enum_variant::generate_default_from_enum_variant,
             generate_derive::generate_derive,
             generate_enum_match_method::generate_enum_is_method,
-            generate_enum_match_method::generate_enum_into_method,
-            generate_enum_match_method::generate_enum_as_method,
+            generate_enum_projection_method::generate_enum_into_method,
+            generate_enum_projection_method::generate_enum_as_method,
             generate_from_impl_for_enum::generate_from_impl_for_enum,
             generate_function::generate_function,
             generate_getter::generate_getter,
diff --git a/crates/ide_assists/src/utils.rs b/crates/ide_assists/src/utils.rs
index 276792bc1..880ab6fe3 100644
--- a/crates/ide_assists/src/utils.rs
+++ b/crates/ide_assists/src/utils.rs
@@ -21,7 +21,7 @@ use syntax::{
 };
 
 use crate::{
-    assist_context::AssistContext,
+    assist_context::{AssistBuilder, AssistContext},
     ast_transform::{self, AstTransform, QualifyPaths, SubstituteTypeParams},
 };
 
@@ -464,3 +464,25 @@ fn generate_impl_text_inner(adt: &ast::Adt, trait_text: Option<&str>, code: &str
 
     buf
 }
+
+pub(crate) fn add_method_to_adt(
+    builder: &mut AssistBuilder,
+    adt: &ast::Adt,
+    impl_def: Option<ast::Impl>,
+    method: &str,
+) {
+    let mut buf = String::with_capacity(method.len() + 2);
+    if impl_def.is_some() {
+        buf.push('\n');
+    }
+    buf.push_str(method);
+
+    let start_offset = impl_def
+        .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
+        .unwrap_or_else(|| {
+            buf = generate_impl_text(&adt, &buf);
+            adt.syntax().text_range().end()
+        });
+
+    builder.insert(start_offset, buf);
+}