Add labels when showing a hovered function type

compiler-core/src/ast.rs

@@ -18,7 +18,7 @@ use crate::type_::error::VariableOrigin;
 use crate::type_::expression::Implementations;
 use crate::type_::printer::Names;
 use crate::type_::{
-    self, Deprecation, ModuleValueConstructor, PatternConstructor, Type, ValueConstructor,
+    self, Deprecation, FieldMap, ModuleValueConstructor, PatternConstructor, Type, ValueConstructor,
 };
 use std::sync::Arc;
 
@@ -747,6 +747,23 @@ pub struct ModuleConstant<T, ConstantRecordTag> {
     pub implementations: Implementations,
 }
 
+impl TypedModuleConstant {
+    pub(crate) fn field_map(&self) -> Option<&FieldMap> {
+        match self.value.as_ref() {
+            Constant::Record { field_map, .. } => field_map.as_ref(),
+            Constant::Int { .. }
+            | Constant::Float { .. }
+            | Constant::String { .. }
+            | Constant::Tuple { .. }
+            | Constant::List { .. }
+            | Constant::BitArray { .. }
+            | Constant::Var { .. }
+            | Constant::StringConcatenation { .. }
+            | Constant::Invalid { .. } => None,
+        }
+    }
+}
+
 pub type UntypedCustomType = CustomType<()>;
 pub type TypedCustomType = CustomType<Arc<Type>>;
 

compiler-core/src/language_server/engine.rs

@@ -14,8 +14,10 @@ use crate::{
     line_numbers::LineNumbers,
     paths::ProjectPaths,
     type_::{
-        self, Deprecation, ModuleInterface, Type, TypeConstructor, ValueConstructor,
-        ValueConstructorVariant, error::VariableOrigin, printer::Printer,
+        self, Deprecation, FieldMap, ModuleInterface, Type, TypeConstructor, ValueConstructor,
+        ValueConstructorVariant,
+        error::VariableOrigin,
+        printer::{Names, Printer},
     },
 };
 use camino::Utf8PathBuf;
@@ -27,7 +29,10 @@ use lsp_types::{
     PrepareRenameResponse, Range, SignatureHelp, SymbolKind, SymbolTag, TextEdit, Url,
     WorkspaceEdit,
 };
-use std::{collections::HashSet, sync::Arc};
+use std::{
+    collections::{HashMap, HashSet},
+    sync::Arc,
+};
 
 use super::{
     DownloadDependencies, MakeLocker,
@@ -1069,10 +1074,18 @@ fn hover_for_function_head(
         .map(|(_, doc)| doc)
         .unwrap_or(&empty_str);
     let function_type = get_function_type(fun);
-    let formatted_type = Printer::new(&module.ast.names).print_type(&function_type);
+
+    let index_to_label = fun
+        .arguments
+        .iter()
+        .enumerate()
+        .filter_map(|(i, arg)| arg.names.get_label().map(|label| (i as u32, label)))
+        .collect::<HashMap<_, _>>();
+
+    let type_ = Printer::new(&module.ast.names).print_with_labels(&function_type, index_to_label);
     let contents = format!(
         "```gleam
-{formatted_type}
+{type_}
 ```
 {documentation}"
     );
@@ -1143,7 +1156,7 @@ fn hover_for_module_constant(
     module: &Module,
 ) -> Hover {
     let empty_str = EcoString::from("");
-    let type_ = Printer::new(&module.ast.names).print_type(&constant.type_);
+    let type_ = print_type_with_field_map(&module.ast.names, &constant.type_, constant.field_map());
     let documentation = constant
         .documentation
         .as_ref()
@@ -1171,7 +1184,12 @@ fn hover_for_expression(
         .unwrap_or("".to_string());
 
     // Show the type of the hovered node to the user
-    let type_ = Printer::new(&module.ast.names).print_type(expression.type_().as_ref());
+    let type_ = print_type_with_field_map(
+        &module.ast.names,
+        &expression.type_(),
+        expression.field_map(),
+    );
+
     let contents = format!(
         "```gleam
 {type_}
@@ -1199,7 +1217,7 @@ fn hover_for_imported_value(
     });
 
     // Show the type of the hovered node to the user
-    let type_ = Printer::new(&module.ast.names).print_type(value.type_.as_ref());
+    let type_ = print_type_with_field_map(&module.ast.names, &value.type_, value.field_map());
     let contents = format!(
         "```gleam
 {type_}
@@ -1212,6 +1230,19 @@ fn hover_for_imported_value(
     }
 }
 
+fn print_type_with_field_map(
+    names: &Names,
+    type_: &Type,
+    field_map: Option<&FieldMap>,
+) -> EcoString {
+    let mut printer = Printer::new(names);
+    if let Some(field_map) = field_map {
+        printer.print_with_labels(type_, field_map.indices_to_labels())
+    } else {
+        printer.print_type(type_)
+    }
+}
+
 fn hover_for_module(
     module: &ModuleInterface,
     location: SrcSpan,

compiler-core/src/language_server/tests/hover.rs

@@ -69,6 +69,96 @@ macro_rules! assert_hover {
     };
 }
 
+#[test]
+fn hover_function_with_labelled_arguments() {
+    let code = "
+pub fn main() {
+  labelled
+}
+
+pub fn labelled(a: Int, label b: String) -> Int { 1 }
+";
+
+    assert_hover!(
+        TestProject::for_source(code),
+        find_position_of("labelled").under_char('b')
+    );
+}
+
+#[test]
+fn hover_constructor_with_labelled_arguments() {
+    let code = "
+pub fn main() {
+    Labelled
+}
+
+pub type Labelled {
+  Labelled(Int, label: String)
+}
+";
+
+    assert_hover!(
+        TestProject::for_source(code),
+        find_position_of("Labelled").under_char('b')
+    );
+}
+
+#[test]
+fn hover_constant_with_labelled_constructor() {
+    let code = "
+pub const wibble = Labelled
+
+pub type Labelled {
+  Labelled(Int, label: String)
+}
+";
+
+    assert_hover!(
+        TestProject::for_source(code),
+        find_position_of("wibble").under_char('i')
+    );
+}
+
+#[test]
+fn hover_imported_labelled_function() {
+    let code = "
+import wibble.{wobble}
+";
+
+    assert_hover!(
+        TestProject::for_source(code)
+            .add_dep_module("wibble", "pub fn wobble(a: Int, label b: String) {}"),
+        find_position_of("wobble").under_char('i')
+    );
+}
+
+#[test]
+fn hover_imported_labelled_constructor() {
+    let code = "
+import wibble.{Wobble}
+";
+
+    assert_hover!(
+        TestProject::for_source(code)
+            .add_dep_module("wibble", "pub type Wobble { Wobble(Int, label: String) }"),
+        find_position_of("Wobble").under_char('i')
+    );
+}
+
+#[test]
+fn hover_labelled_function_head() {
+    let code = "
+pub fn main(a, label b) {
+  a + b
+}
+";
+
+    assert_hover!(
+        TestProject::for_source(code),
+        find_position_of("main").under_char('i')
+    );
+}
+
 #[test]
 fn hover_function_definition() {
     assert_hover!(

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_constant_with_labelled_constructor.snap

@@ -0,0 +1,18 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\npub const wibble = Labelled\n\npub type Labelled {\n  Labelled(Int, label: String)\n}\n"
+---
+pub const wibble = Labelled
+▔▔▔▔▔▔▔▔▔▔▔↑▔▔▔▔           
+
+pub type Labelled {
+  Labelled(Int, label: String)
+}
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: String) -> Labelled\n```\n",
+    ),
+)

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_constructor_with_labelled_arguments.snap

@@ -0,0 +1,20 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\npub fn main() {\n    Labelled\n}\n\npub type Labelled {\n  Labelled(Int, label: String)\n}\n"
+---
+pub fn main() {
+    Labelled
+    ▔▔↑▔▔▔▔▔
+}
+
+pub type Labelled {
+  Labelled(Int, label: String)
+}
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: String) -> Labelled\n```\n",
+    ),
+)

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_function_with_labelled_arguments.snap

@@ -0,0 +1,18 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\npub fn main() {\n  labelled\n}\n\npub fn labelled(a: Int, label b: String) -> Int { 1 }\n"
+---
+pub fn main() {
+  labelled
+  ▔▔↑▔▔▔▔▔
+}
+
+pub fn labelled(a: Int, label b: String) -> Int { 1 }
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: String) -> Int\n```\n",
+    ),
+)

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_imported_labelled_constructor.snap

@@ -0,0 +1,14 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\nimport wibble.{Wobble}\n"
+---
+import wibble.{Wobble}
+               ↑▔▔▔▔▔ 
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: String) -> wibble.Wobble\n```\n",
+    ),
+)

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_imported_labelled_function.snap

@@ -0,0 +1,14 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\nimport wibble.{wobble}\n"
+---
+import wibble.{wobble}
+               ↑▔▔▔▔▔ 
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: String) -> a\n```\n",
+    ),
+)

compiler-core/src/language_server/tests/snapshots/gleam_core__language_server__tests__hover__hover_labelled_function_head.snap

@@ -0,0 +1,16 @@
+---
+source: compiler-core/src/language_server/tests/hover.rs
+expression: "\npub fn main(a, label b) {\n  a + b\n}\n"
+---
+pub fn main(a, label b) {
+▔▔▔▔▔▔▔▔▔↑▔▔▔▔▔▔▔▔▔▔▔▔▔  
+  a + b
+}
+
+
+----- Hover content -----
+Scalar(
+    String(
+        "```gleam\nfn(Int, label: Int) -> Int\n```\n",
+    ),
+)