Auto merge of rust-lang#12730 - Alexendoo:lint-groups-workspace-priority, r=xFrednet

Lint direct priority conflicts in `[workspace.lints]`

Partially addresses rust-lang#12729

This still doesn't do any workspace resolution stuff, so it will not catch any virtual workspaces or conflicts from inherited definitions. But while we're parsing the `Cargo.toml` we might as well check the workspace definitions if we find them

changelog: none

Author: bors

clippy_lints/src/cargo/lint_groups_priority.rs

@@ -49,17 +49,26 @@ impl LintConfig {
 
 type LintTable = BTreeMap<Spanned<String>, Spanned<LintConfig>>;
 
-#[derive(Deserialize, Debug)]
+#[derive(Deserialize, Debug, Default)]
 struct Lints {
     #[serde(default)]
     rust: LintTable,
     #[serde(default)]
     clippy: LintTable,
 }
 
+#[derive(Deserialize, Debug, Default)]
+struct Workspace {
+    #[serde(default)]
+    lints: Lints,
+}
+
 #[derive(Deserialize, Debug)]
 struct CargoToml {
+    #[serde(default)]
     lints: Lints,
+    #[serde(default)]
+    workspace: Workspace,
 }
 
 #[derive(Default, Debug)]
@@ -164,5 +173,7 @@ pub fn check(cx: &LateContext<'_>) {
 
         check_table(cx, cargo_toml.lints.rust, &rustc_groups, &file);
         check_table(cx, cargo_toml.lints.clippy, &clippy_groups, &file);
+        check_table(cx, cargo_toml.workspace.lints.rust, &rustc_groups, &file);
+        check_table(cx, cargo_toml.workspace.lints.clippy, &clippy_groups, &file);
     }
 }

tests/ui-cargo/lint_groups_priority/fail/Cargo.stderr

@@ -42,4 +42,32 @@ help: to have lints override the group set `pedantic` to a lower priority
 19 | pedantic = { level = "warn", priority = -2 }
    |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-error: could not compile `fail` (lib) due to 3 previous errors
+error: lint group `rust_2018_idioms` has the same priority (0) as a lint
+  --> Cargo.toml:23:1
+   |
+23 | rust_2018_idioms = "warn"
+   | ^^^^^^^^^^^^^^^^   ------ has an implicit priority of 0
+24 | bare_trait_objects = "allow"
+   | ------------------ has the same priority as this lint
+   |
+   = note: the order of the lints in the table is ignored by Cargo
+help: to have lints override the group set `rust_2018_idioms` to a lower priority
+   |
+23 | rust_2018_idioms = { level = "warn", priority = -1 }
+   |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: lint group `pedantic` has the same priority (0) as a lint
+  --> Cargo.toml:27:1
+   |
+27 | pedantic = "warn"
+   | ^^^^^^^^   ------ has an implicit priority of 0
+28 | similar_names = "allow"
+   | ------------- has the same priority as this lint
+   |
+   = note: the order of the lints in the table is ignored by Cargo
+help: to have lints override the group set `pedantic` to a lower priority
+   |
+27 | pedantic = { level = "warn", priority = -1 }
+   |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: could not compile `fail` (lib) due to 5 previous errors

tests/ui-cargo/lint_groups_priority/fail/Cargo.toml

@@ -18,3 +18,11 @@ deprecated  = "allow"
 [lints.clippy]
 pedantic = { level = "warn", priority = -1 }
 similar_names = { level = "allow", priority = -1 }
+
+[workspace.lints.rust]
+rust_2018_idioms = "warn"
+bare_trait_objects = "allow"
+
+[workspace.lints.clippy]
+pedantic = "warn"
+similar_names = "allow"