fix null value crash in analysis.zig (#2252)

Author: The-Emperor10

src/analysis.zig

@@ -1643,7 +1643,7 @@ fn resolveTypeOfNodeUncached(analyser: *Analyser, node_handle: NodeWithHandle) e
                 const ptyp = try analyser.arena.allocator().create(Type);
                 ptyp.* = argument_type;
 
-                const symbol = offsets.identifierTokenToNameSlice(func_tree, param.name_token.?);
+                const symbol = if (param.name_token) |name_token| offsets.identifierTokenToNameSlice(func_tree, name_token) else "";
                 meta_params.appendAssumeCapacity(.{ .index = param_index, .symbol = symbol, .typ = ptyp });
             }
 

tests/lsp_features/completion.zig

@@ -422,6 +422,14 @@ test "recursive generic function" {
     , &.{});
 }
 
+test "generic function without body" {
+    try testCompletion(
+        \\const Foo: fn (type) type = undefined;
+        \\const Bar = Foo(u32);
+        \\const value = Bar.<cursor>;
+    , &.{});
+}
+
 test "std.ArrayList" {
     if (!std.process.can_spawn) return error.SkipZigTest;
     try testCompletion(