fix(resolver): Include dep spec in rejected versions error

Author: epage

src/cargo/core/resolver/errors.rs

@@ -226,10 +226,18 @@ pub(super) fn activation_error(
             Ok(c) => c,
             Err(e) => return to_resolve_err(e),
         };
+
+        let locked_version = dep
+            .version_req()
+            .locked_version()
+            .map(|v| format!(" (locked to {})", v))
+            .unwrap_or_default();
         let _ = writeln!(
             &mut msg,
-            "no matching versions for `{}` found",
-            dep.package_name()
+            "failed to select a version for the requirement `{} = \"{}\"`{}",
+            dep.package_name(),
+            dep.version_req(),
+            locked_version
         );
         for candidate in version_candidates {
             match candidate {

tests/testsuite/registry.rs

@@ -862,7 +862,7 @@ fn relying_on_a_yank_is_bad_http() {
     let _server = setup_http();
     relying_on_a_yank_is_bad(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `baz` found
+[ERROR] failed to select a version for the requirement `baz = "=0.0.2"`
   version 0.0.2 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `bar v0.0.1`
@@ -875,7 +875,7 @@ required by package `bar v0.0.1`
 fn relying_on_a_yank_is_bad_git() {
     relying_on_a_yank_is_bad(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `baz` found
+[ERROR] failed to select a version for the requirement `baz = "=0.0.2"`
   version 0.0.2 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `bar v0.0.1`
@@ -922,7 +922,7 @@ fn yanks_in_lockfiles_are_ok_http() {
 "#]],
         str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "*"`
   version 0.0.1 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.0.1 ([ROOT]/foo)`
@@ -940,7 +940,7 @@ fn yanks_in_lockfiles_are_ok_git() {
 "#]],
         str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "*"`
   version 0.0.1 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.0.1 ([ROOT]/foo)`
@@ -993,7 +993,7 @@ fn yanks_in_lockfiles_are_ok_for_other_update_http() {
 "#]],
         str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "*"`
   version 0.0.1 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.0.1 ([ROOT]/foo)`
@@ -1017,7 +1017,7 @@ fn yanks_in_lockfiles_are_ok_for_other_update_git() {
 "#]],
         str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "*"`
   version 0.0.1 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.0.1 ([ROOT]/foo)`
@@ -3228,7 +3228,7 @@ fn unknown_index_version_error() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "^1.0"`
   version 1.0.1 requires a Cargo version that supports index version 4294967295
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.1.0 ([ROOT]/foo)`
@@ -3266,7 +3266,7 @@ fn unknown_index_version_with_msrv_error() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] no matching versions for `bar` found
+[ERROR] failed to select a version for the requirement `bar = "^1.0"`
   version 1.0.1 requires cargo 1.2345
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `foo v0.1.0 ([ROOT]/foo)`