deduplicate lints

compiler/qsc_linter/Cargo.toml

@@ -15,6 +15,7 @@ qsc_hir = { path = "../qsc_hir" }
 qsc_data_structures = { path = "../qsc_data_structures" }
 qsc_frontend = { path = "../qsc_frontend" }
 qsc_doc_gen = { path = "../qsc_doc_gen" }
+rustc-hash = { workspace = true }
 serde = { workspace = true }
 thiserror = { workspace = true }
 

compiler/qsc_linter/src/linter.rs

@@ -32,9 +32,15 @@ pub fn run_lints(
     let mut lints = Vec::new();
     lints.append(&mut ast_lints);
     lints.append(&mut hir_lints);
+    remove_duplicates(&mut lints);
     lints
 }
 
+pub(crate) fn remove_duplicates<T: Eq + std::hash::Hash + Clone>(vec: &mut Vec<T>) {
+    let mut seen = rustc_hash::FxHashSet::default();
+    vec.retain(|x| seen.insert(x.clone()));
+}
+
 #[derive(Clone, Copy)]
 pub(crate) struct Compilation<'a> {
     pub package_store: &'a PackageStore,
@@ -117,6 +123,21 @@ pub struct Lint {
     pub code_action_edits: Vec<(String, Span)>,
 }
 
+impl std::hash::Hash for Lint {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.span.hash(state);
+        self.kind.hash(state);
+    }
+}
+
+impl std::cmp::PartialEq for Lint {
+    fn eq(&self, other: &Self) -> bool {
+        self.span == other.span && self.kind == other.kind
+    }
+}
+
+impl std::cmp::Eq for Lint {}
+
 impl std::fmt::Display for Lint {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{}", self.message)
@@ -188,7 +209,7 @@ pub struct LintConfig {
 }
 
 /// Represents a lint name.
-#[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq, Hash)]
 #[serde(untagged)]
 pub enum LintKind {
     /// AST lint name.

compiler/qsc_linter/src/linter/ast.rs

@@ -185,7 +185,7 @@ macro_rules! declare_ast_lints {
         use serde::{Deserialize, Serialize};
 
         /// An enum listing all existing AST lints.
-        #[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq)]
+        #[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq, Hash)]
         #[serde(rename_all = "camelCase")]
         pub enum AstLint {
             $(

compiler/qsc_linter/src/linter/hir.rs

@@ -149,7 +149,7 @@ macro_rules! declare_hir_lints {
         use serde::{Deserialize, Serialize};
 
         /// An enum listing all existing HIR lints.
-        #[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq)]
+        #[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq, Eq, Hash)]
         #[serde(rename_all = "camelCase")]
         pub enum HirLint {
             $(

compiler/qsc_linter/src/tests.rs

@@ -1,19 +1,39 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
-use crate::{
-    linter::{ast::run_ast_lints, hir::run_hir_lints, Compilation},
-    Lint, LintConfig, LintLevel,
-};
+use crate::{run_lints, Lint, LintLevel};
 use expect_test::{expect, Expect};
 use indoc::indoc;
 use qsc_data_structures::{
     language_features::LanguageFeatures, span::Span, target::TargetCapabilityFlags,
 };
-use qsc_frontend::compile::{self, CompileUnit, PackageStore, SourceMap};
+use qsc_frontend::compile::{self, PackageStore, SourceMap};
 use qsc_hir::hir::CallableKind;
 use qsc_passes::PackageType;
 
+#[test]
+fn check_that_hir_lints_are_deduplicated_in_operations_with_multiple_specializations() {
+    check(
+        "
+        operation Main() : Unit {}
+        operation LintProblem() : Unit is Adj + Ctl {
+            use q = Qubit();
+            0.0 == 0.0;
+        }",
+        &expect![[r#"
+            [
+                SrcLint {
+                    source: "0.0 == 0.0",
+                    level: Warn,
+                    message: "strict comparison of doubles",
+                    help: "consider comparing them with some margin of error",
+                    code_action_edits: [],
+                },
+            ]
+        "#]],
+    );
+}
+
 #[test]
 fn daisy_chain_lint() {
     check(
@@ -805,21 +825,3 @@ impl SrcLint {
         }
     }
 }
-
-fn run_lints(
-    package_store: &PackageStore,
-    compile_unit: &CompileUnit,
-    config: Option<&[LintConfig]>,
-) -> Vec<Lint> {
-    let compilation = Compilation {
-        package_store,
-        compile_unit,
-    };
-
-    let mut ast_lints = run_ast_lints(&compile_unit.ast.package, config, compilation);
-    let mut hir_lints = run_hir_lints(&compile_unit.package, config, compilation);
-    let mut lints = Vec::new();
-    lints.append(&mut ast_lints);
-    lints.append(&mut hir_lints);
-    lints
-}