Michaelrfairhurst/declarations8 rule 6-2-3 do not duplicate source code

[MichaelRFairhurst]

Description

This rule is somewhat interesting because 6-2-1 already mostly does things that 6-2-3 does. We can't expressly detect ODR violations, so 6-2-1 looks for repeated names across files. However, there's still room to make 6-2-1 stricter and that's what this query does. Essentially, 6-2-3 gives us permission to flag cases that we considered likely false positives in 6-2-1.

Change request type

• Release or process automation (GitHub workflows, internal scripts)
• Internal documentation
• External documentation
• Query files (.ql, .qll, .qls or unit tests)
• External scripts (analysis report or other code shipped as part of a release)

Rules with added or modified queries

• No rules added
• Queries have been added for the following rules:
  • RULE-6-2-3
• Queries have been modified for the following rules:
  • rule number here

Release change checklist

A change note (development_handbook.md#change-notes) is required for any pull request which modifies:

• The structure or layout of the release artifacts.
• The evaluation performance (memory, execution time) of an existing query.
• The results of an existing query in any circumstance.

If you are only adding new rule queries, a change note is not required.

Author: Is a change note required?

• Yes
• No

🚨🚨🚨
Reviewer: Confirm that format of shared queries (not the .qll file, the
.ql file that imports it) is valid by running them within VS Code.

• Confirmed

Reviewer: Confirm that either a change note is not required or the change note is required and has been added.

• Confirmed

Query development review checklist

For PRs that add new queries or modify existing queries, the following checklist should be completed by both the author and reviewer:

Author

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

Reviewer

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

[Copilot]

Pull request overview

This PR adds new MISRA C++:2023 RULE-6-2-3 queries (and their tests) to detect duplicate entity implementations/types across files and misplaced template specializations, while also refactoring shared anonymous-namespace linkage logic used by multiple queries.

Changes:

• Add a new C++ rule package entry for RULE-6-2-3 and three associated query definitions.
• Add unit tests (.cpp/.h) and .expected/.qlref files covering duplicate type definitions and template specialization placement.
• Refactor Linkage.qll anonymous-namespace detection (introducing WithinAnonymousNamespace) and wire the new package into the exclusions metadata, with a change note.

Show a summary per file

File	Description
rule_packages/cpp/Declarations8.json	Registers RULE-6-2-3 and its three queries in the rule package metadata.
cpp/misra/src/rules/RULE-6-2-3/SourceCodeImplementedOnlyOnce.ql	New query intended to detect multiple implementations of an entity across source locations.
cpp/misra/src/rules/RULE-6-2-3/TemplateSpecializationWrongLocation.ql	New query to flag template specializations declared outside the primary template / specialized-type file.
cpp/misra/src/rules/RULE-6-2-3/DuplicateTypeDefinitions.ql	New query to flag duplicate type definitions across files.
cpp/misra/test/rules/RULE-6-2-3/test.cpp	Primary test file containing compliant/non-compliant cases and includes for specialization tests.
cpp/misra/test/rules/RULE-6-2-3/test2.cpp	Secondary TU to exercise cross-file duplication behavior.
cpp/misra/test/rules/RULE-6-2-3/template.h	Defines primary templates and compliant specializations for location tests.
cpp/misra/test/rules/RULE-6-2-3/class.h	Defines types used as specialization arguments for location tests.
cpp/misra/test/rules/RULE-6-2-3/compliant_specialization.h	Compliant specialization cases (specialized type defined in same file).
cpp/misra/test/rules/RULE-6-2-3/noncompliant_specialization.h	Non-compliant specialization cases expected to be flagged.
cpp/misra/test/rules/RULE-6-2-3/SourceCodeImplementedOnlyOnce.qlref	Test reference to the production query.
cpp/misra/test/rules/RULE-6-2-3/SourceCodeImplementedOnlyOnce.expected	Expected results for the inline-entity duplication query.
cpp/misra/test/rules/RULE-6-2-3/TemplateSpecializationWrongLocation.qlref	Test reference to the production query.
cpp/misra/test/rules/RULE-6-2-3/TemplateSpecializationWrongLocation.expected	Expected results for the specialization-location query.
cpp/misra/test/rules/RULE-6-2-3/DuplicateTypeDefinitions.qlref	Test reference to the production query.
cpp/misra/test/rules/RULE-6-2-3/DuplicateTypeDefinitions.expected	Expected results for the duplicate-type-definition query.
cpp/common/src/codingstandards/cpp/exclusions/cpp/RuleMetadata.qll	Wires the new Declarations8 package into the exclusions metadata dispatch.
cpp/common/src/codingstandards/cpp/exclusions/cpp/Declarations8.qll	Adds autogenerated exclusions metadata and query handles for Declarations8.
cpp/common/src/codingstandards/cpp/Linkage.qll	Refactors nested anonymous-namespace detection via WithinAnonymousNamespace.
change_notes/2026-04-19-refactor-nested-anonymous-namespace-logic.md	Change note covering the Linkage refactor impact statement.

Copilot's findings

Comments suppressed due to low confidence (1)

cpp/misra/src/rules/RULE-6-2-3/SourceCodeImplementedOnlyOnce.ql:39

• This query only checks Function.isInline(), but the alert message says "Inline variable". That’s misleading for users (and contradicts the stated implementation scope). Update the message (and any related wording) to refer to an inline function (or more generally an inline entity) rather than an inline variable.

select d1,
  "Inline variable '" + d1.getName() +
    "' is defined in multiple files, violating the source code uniqueness requirement."

• Files reviewed: 20/20 changed files
• Comments generated: 3

[Copilot]

The query metadata @name field includes a duplicated rule prefix ("RULE-6-2-3: RULE-6-2-3: …"). This will show up in tooling/UI and is inconsistent with the rule package name; please remove the duplicated "RULE-6-2-3:" segment.

Suggested change

	* @name RULE-6-2-3: RULE-6-2-3: Template specializations in wrong location
	* @name RULE-6-2-3: Template specializations in wrong location

[Copilot]

The query metadata @name field includes a duplicated rule prefix ("RULE-6-2-3: RULE-6-2-3: …"). This will show up in tooling/UI and is inconsistent with the rule package name; please remove the duplicated "RULE-6-2-3:" segment.

Suggested change

	* @name RULE-6-2-3: RULE-6-2-3: Duplicate type definitions across files
	* @name RULE-6-2-3: Duplicate type definitions across files

[Copilot]

hasQualifiedName(namespace, name) only compares the qualified name (not the full signature), so this can incorrectly report overloads (or other distinct entities) that share the same name across files. To ensure you only match the same entity, compare the underlying declarations directly (for example d1.getDeclaration() = d2.getDeclaration()), and then you can drop the extra namespace/name string bindings.

This issue also appears on line 37 of the same file.