Ignore lifetime params in substitutions

Author: Veykril

crates/hir_def/src/item_tree.rs

@@ -246,7 +246,10 @@ struct GenericParamsStorage {
 
 impl GenericParamsStorage {
     fn alloc(&mut self, params: GenericParams) -> GenericParamsId {
-        if params.types.is_empty() && params.where_predicates.is_empty() {
+        if params.types.is_empty()
+            && params.lifetimes.is_empty()
+            && params.where_predicates.is_empty()
+        {
             return GenericParamsId::EMPTY;
         }
 

crates/hir_ty/src/infer/expr.rs

@@ -856,7 +856,12 @@ impl<'a> InferenceContext<'a> {
         // handle provided type arguments
         if let Some(generic_args) = generic_args {
             // if args are provided, it should be all of them, but we can't rely on that
-            for arg in generic_args.args.iter().take(type_params) {
+            for arg in generic_args
+                .args
+                .iter()
+                .filter(|arg| matches!(arg, GenericArg::Type(_)))
+                .take(type_params)
+            {
                 match arg {
                     GenericArg::Type(type_ref) => {
                         let ty = self.make_ty(type_ref);

crates/hir_ty/src/lower.rs

@@ -565,7 +565,13 @@ fn substs_from_path_segment(
             if generic_args.has_self_type { self_params + type_params } else { type_params };
         let skip = if generic_args.has_self_type && self_params == 0 { 1 } else { 0 };
         // if args are provided, it should be all of them, but we can't rely on that
-        for arg in generic_args.args.iter().skip(skip).take(expected_num) {
+        for arg in generic_args
+            .args
+            .iter()
+            .filter(|arg| matches!(arg, GenericArg::Type(_)))
+            .skip(skip)
+            .take(expected_num)
+        {
             match arg {
                 GenericArg::Type(type_ref) => {
                     had_explicit_type_args = true;