fix: fix parameter info with missing arguments

crates/ide-completion/src/context/analysis.rs

@@ -657,7 +657,7 @@ fn expected_type_and_name<'db>(
                     cov_mark::hit!(expected_type_fn_param);
                     ActiveParameter::at_token(
                         sema,
-                       token.clone(),
+                        token.clone(),
                     ).map(|ap| {
                         let name = ap.ident().map(NameOrNameRef::Name);
                         (Some(ap.ty), name)

crates/ide-completion/src/context/tests.rs

@@ -90,6 +90,20 @@ fn bar(x: u32) {}
 "#,
         expect![[r#"ty: u32, name: x"#]],
     );
+    check_expected_type_and_name(
+        r#"
+fn foo() { bar(, $0); }
+fn bar(x: u32, y: i32) {}
+"#,
+        expect![[r#"ty: i32, name: y"#]],
+    );
+    check_expected_type_and_name(
+        r#"
+fn foo() { bar(, c$0); }
+fn bar(x: u32, y: i32) {}
+"#,
+        expect![[r#"ty: i32, name: y"#]],
+    );
 }
 
 #[test]

crates/ide-db/src/active_parameter.rs

@@ -5,7 +5,7 @@ use hir::{InFile, Semantics, Type};
 use parser::T;
 use span::TextSize;
 use syntax::{
-    AstNode, NodeOrToken, SyntaxToken,
+    AstNode, NodeOrToken, SyntaxKind, SyntaxNode, SyntaxToken,
     ast::{self, AstChildren, HasArgList, HasAttrs, HasName},
     match_ast,
 };
@@ -102,8 +102,7 @@ pub fn callable_for_node<'db>(
         arg_list
             .syntax()
             .children_with_tokens()
-            .filter_map(NodeOrToken::into_token)
-            .filter(|t| t.kind() == T![,])
+            .filter_map(into_comma)
             .take_while(|t| t.text_range().start() <= offset)
             .count()
     });
@@ -162,8 +161,7 @@ pub fn generic_def_for_node(
     let active_param = generic_arg_list
         .syntax()
         .children_with_tokens()
-        .filter_map(NodeOrToken::into_token)
-        .filter(|t| t.kind() == T![,])
+        .filter_map(into_comma)
         .take_while(|t| t.text_range().start() <= token.text_range().start())
         .count();
 
@@ -174,3 +172,12 @@ pub fn generic_def_for_node(
 
     Some((def, active_param, first_arg_is_non_lifetime, variant))
 }
+
+fn into_comma(it: NodeOrToken<SyntaxNode, SyntaxToken>) -> Option<SyntaxToken> {
+    let token = match it {
+        NodeOrToken::Token(it) => it,
+        NodeOrToken::Node(node) if node.kind() == SyntaxKind::ERROR => node.first_token()?,
+        NodeOrToken::Node(_) => return None,
+    };
+    (token.kind() == T![,]).then_some(token)
+}