From de082127d8d2e50f0df29e44ce4921d5bd404ec9 Mon Sep 17 00:00:00 2001
From: Chayim Refael Friedman <chayimfr@gmail.com>
Date: Thu, 24 Apr 2025 09:06:04 +0300
Subject: [PATCH] Correctly set `infer_args = true` in more places

Previously this being incorrect wasn't a problem, it just meant we put an error type that then changed to infer type, so exactly what rustc does at the end. But now there is a diagnostic.
---
 src/tools/rust-analyzer/crates/hir-ty/src/infer.rs   |  2 +-
 .../rust-analyzer/crates/hir-ty/src/infer/path.rs    |  2 +-
 src/tools/rust-analyzer/crates/hir-ty/src/lower.rs   |  2 +-
 .../rust-analyzer/crates/hir-ty/src/lower/path.rs    | 12 +++++++-----
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs b/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
index 38807b6f7207..228e67a60f41 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
@@ -1675,7 +1675,7 @@ impl<'a> InferenceContext<'a> {
                     // `lower_partly_resolved_path()` returns `None` as type namespace unless
                     // `remaining_segments` is empty, which is never the case here. We don't know
                     // which namespace the new `ty` is in until normalized anyway.
-                    (ty, _) = path_ctx.lower_partly_resolved_path(resolution, false);
+                    (ty, _) = path_ctx.lower_partly_resolved_path(resolution, true);
                     tried_resolving_once = true;
 
                     ty = self.table.insert_type_vars(ty);
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/infer/path.rs b/src/tools/rust-analyzer/crates/hir-ty/src/infer/path.rs
index 88638d1ae915..9d4bbe53464d 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/infer/path.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/infer/path.rs
@@ -177,7 +177,7 @@ impl InferenceContext<'_> {
             let ty = self.table.normalize_associated_types_in(ty);
 
             path_ctx.ignore_last_segment();
-            let (ty, _) = path_ctx.lower_ty_relative_path(ty, orig_ns);
+            let (ty, _) = path_ctx.lower_ty_relative_path(ty, orig_ns, true);
             drop_ctx(ctx, no_diagnostics);
             let ty = self.table.insert_type_vars(ty);
             let ty = self.table.normalize_associated_types_in(ty);
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
index 740882521cd1..34524668499a 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
@@ -508,7 +508,7 @@ impl<'a> TyLoweringContext<'a> {
         if let Some(type_ref) = path.type_anchor() {
             let (ty, res) = self.lower_ty_ext(type_ref);
             let mut ctx = self.at_path(path_id);
-            return ctx.lower_ty_relative_path(ty, res);
+            return ctx.lower_ty_relative_path(ty, res, false);
         }
 
         let mut ctx = self.at_path(path_id);
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lower/path.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lower/path.rs
index 6b71e98b0323..e01e8ea0ba1a 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lower/path.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lower/path.rs
@@ -137,12 +137,13 @@ impl<'a, 'b> PathLoweringContext<'a, 'b> {
         ty: Ty,
         // We need the original resolution to lower `Self::AssocTy` correctly
         res: Option<TypeNs>,
+        infer_args: bool,
     ) -> (Ty, Option<TypeNs>) {
         match self.segments.len() - self.current_segment_idx {
             0 => (ty, res),
             1 => {
                 // resolve unselected assoc types
-                (self.select_associated_type(res), None)
+                (self.select_associated_type(res, infer_args), None)
             }
             _ => {
                 // FIXME report error (ambiguous associated type)
@@ -182,7 +183,7 @@ impl<'a, 'b> PathLoweringContext<'a, 'b> {
                                 // this point (`trait_ref.substitution`).
                                 let substitution = self.substs_from_path_segment(
                                     associated_ty.into(),
-                                    false,
+                                    infer_args,
                                     None,
                                     true,
                                 );
@@ -277,7 +278,7 @@ impl<'a, 'b> PathLoweringContext<'a, 'b> {
         };
 
         self.skip_resolved_segment();
-        self.lower_ty_relative_path(ty, Some(resolution))
+        self.lower_ty_relative_path(ty, Some(resolution), infer_args)
     }
 
     fn handle_type_ns_resolution(&mut self, resolution: &TypeNs) {
@@ -473,7 +474,7 @@ impl<'a, 'b> PathLoweringContext<'a, 'b> {
         Some(res)
     }
 
-    fn select_associated_type(&mut self, res: Option<TypeNs>) -> Ty {
+    fn select_associated_type(&mut self, res: Option<TypeNs>, infer_args: bool) -> Ty {
         let Some(res) = res else {
             return TyKind::Error.intern(Interner);
         };
@@ -507,7 +508,8 @@ impl<'a, 'b> PathLoweringContext<'a, 'b> {
                 // generic params. It's inefficient to splice the `Substitution`s, so we may want
                 // that method to optionally take parent `Substitution` as we already know them at
                 // this point (`t.substitution`).
-                let substs = self.substs_from_path_segment(associated_ty.into(), false, None, true);
+                let substs =
+                    self.substs_from_path_segment(associated_ty.into(), infer_args, None, true);
 
                 let substs = Substitution::from_iter(
                     Interner,