Add support for graying out unused imports

4 files changed, 45 insertions, 30 deletions

diff --git a/src/common/config.odin b/src/common/config.odin
index 5b2923c..ae5597f 100644
--- a/src/common/config.odin
+++ b/src/common/config.odin
@@ -21,6 +21,7 @@ Config :: struct {
 	enable_hover:                      bool,
 	enable_document_symbols:           bool,
 	enable_semantic_tokens:            bool,
+	enable_unused_imports_reporting:   bool,
 	enable_inlay_hints:                bool,
 	enable_inlay_hints_params:         bool,
 	enable_inlay_hints_default_params: bool,
diff --git a/src/server/documents.odin b/src/server/documents.odin
index cf8a344..591c56c 100644
--- a/src/server/documents.odin
+++ b/src/server/documents.odin
@@ -76,7 +76,7 @@ document_get_allocator :: proc() -> ^virtual.Arena {
 		return pop(&document_storage.free_allocators)
 	} else {
 		allocator := new(virtual.Arena)
-		_ = virtual.arena_init_growing(allocator) 
+		_ = virtual.arena_init_growing(allocator)
 		return allocator
 	}
 }
@@ -319,26 +319,50 @@ document_refresh :: proc(document: ^Document, config: ^common.Config, writer: ^W
 		return .None
 	}
 
-	if writer != nil && len(errors) > 0 && !config.disable_parser_errors {
+	if writer != nil && !config.disable_parser_errors {
 		document.diagnosed_errors = true
 
+		diagnostics := make([dynamic]Diagnostic, 0, len(errors), context.temp_allocator)
+
 		params := NotificationPublishDiagnosticsParams {
-			uri         = document.uri.uri,
-			diagnostics = make([]Diagnostic, len(errors), context.temp_allocator),
+			uri = document.uri.uri,
 		}
 
 		for error, i in errors {
-			params.diagnostics[i] = Diagnostic {
-				range = common.Range {
-					start = common.Position{line = error.line - 1, character = 0},
-					end = common.Position{line = error.line, character = 0},
+			append(
+				&diagnostics,
+				Diagnostic {
+					range = common.Range {
+						start = common.Position{line = error.line - 1, character = 0},
+						end = common.Position{line = error.line, character = 0},
+					},
+					severity = DiagnosticSeverity.Error,
+					code = "Syntax",
+					message = error.message,
 				},
-				severity = DiagnosticSeverity.Error,
-				code = "Syntax",
-				message = error.message,
+			)
+		}
+
+		if config.enable_unused_imports_reporting {
+			unused_imports := find_unused_imports(document, context.temp_allocator)
+
+			for imp in unused_imports {
+				append(
+					&diagnostics,
+					Diagnostic {
+						range = common.get_token_range(imp.import_decl, document.ast.src),
+						severity = DiagnosticSeverity.Hint,
+						code = "Unused",
+						message = "unused import",
+						tags = {.Unnecessary},
+					},
+				)
 			}
+
 		}
 
+		params.diagnostics = diagnostics[:]
+
 		notifaction := Notification {
 			jsonrpc = "2.0",
 			method  = "textDocument/publishDiagnostics",
@@ -348,25 +372,6 @@ document_refresh :: proc(document: ^Document, config: ^common.Config, writer: ^W
 		send_notification(notifaction, writer)
 	}
 
-	if writer != nil && len(errors) == 0 {
-		//send empty diagnosis to remove the clients errors
-		if document.diagnosed_errors {
-
-			notifaction := Notification {
-				jsonrpc = "2.0",
-				method = "textDocument/publishDiagnostics",
-				params = NotificationPublishDiagnosticsParams {
-					uri = document.uri.uri,
-					diagnostics = make([]Diagnostic, len(errors), context.temp_allocator),
-				},
-			}
-
-			document.diagnosed_errors = false
-
-			send_notification(notifaction, writer)
-		}
-	}
-
 	return .None
 }
 
diff --git a/src/server/requests.odin b/src/server/requests.odin
index 0cbcd99..355cf1b 100644
--- a/src/server/requests.odin
+++ b/src/server/requests.odin
@@ -362,6 +362,7 @@ read_ols_initialize_options :: proc(config: ^common.Config, ols_config: OlsConfi
 	config.enable_format = ols_config.enable_format.(bool) or_else config.enable_format
 	config.enable_hover = ols_config.enable_hover.(bool) or_else config.enable_hover
 	config.enable_semantic_tokens = ols_config.enable_semantic_tokens.(bool) or_else config.enable_semantic_tokens
+	config.enable_unused_imports_reporting = ols_config.enable_unused_imports_reporting.(bool) or_else config.enable_unused_imports_reporting
 	config.enable_procedure_context =
 		ols_config.enable_procedure_context.(bool) or_else config.enable_procedure_context
 	config.enable_snippets = ols_config.enable_snippets.(bool) or_else config.enable_snippets
@@ -614,6 +615,7 @@ request_initialize :: proc(
 	config.enable_format = true
 	config.enable_hover = true
 	config.enable_semantic_tokens = false
+	config.enable_unused_imports_reporting = true
 	config.enable_procedure_context = false
 	config.enable_snippets = false
 	config.enable_references = true
diff --git a/src/server/types.odin b/src/server/types.odin
index 6442503..75161c5 100644
--- a/src/server/types.odin
+++ b/src/server/types.odin
@@ -274,11 +274,17 @@ DiagnosticSeverity :: enum {
 	Hint        = 4,
 }
 
+ DiagnosticTag :: enum int {
+	Unnecessary = 1,
+	Deprecated  = 2,
+ }
+
 Diagnostic :: struct {
 	range:    common.Range,
 	severity: DiagnosticSeverity,
 	code:     string,
 	message:  string,
+	tags:     [1]DiagnosticTag,
 }
 
 DidOpenTextDocumentParams :: struct {
@@ -417,6 +423,7 @@ OlsConfig :: struct {
 	enable_inlay_hints_params:         Maybe(bool),
 	enable_inlay_hints_default_params: Maybe(bool),
 	enable_semantic_tokens:            Maybe(bool),
+	enable_unused_imports_reporting:   Maybe(bool),
 	enable_procedure_context:          Maybe(bool),
 	enable_snippets:                   Maybe(bool),
 	enable_procedure_snippet:          Maybe(bool),