Remove slow regex from threading analyzers

[AArnott]

Root cause: Both NegatableTypeOrMemberReferenceRegex and MemberReferenceRegex contained (?<typeName>[^\[\]\:]+)+ — a character-class group with an unnecessary outer + quantifier. When the overall match failed on a long type name, the regex engine tried exponentially many ways to split the type-name substring across the group, causing catastrophic backtracking.

Fix: Removed both Regex fields and RegexMatchTimeout entirely from CommonInterest.cs, replacing each call site with custom string parsers.

Also add an mcp.json file.

[Copilot]

Pull request overview

Removes regex-based parsing from threading analyzers to avoid pathological backtracking/timeout scenarios and improve performance determinism.

Changes:

• Removed regex fields (and timeout handling) used to parse additional-file entries.
• Added non-regex parsers for type/member reference lines and updated call sites to use them.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/Microsoft.VisualStudio.Threading.Analyzers/CommonInterest.cs:91

• SplitQualifiedIdentifier returns a non-null string type name, but the deconstruction uses string? typeName, which can trigger nullable warnings when passing typeName to QualifiedType (expects string). Consider deconstructing into string typeName (or otherwise ensure the value is statically non-null).

            (ImmutableArray<string> containingNamespace, string? typeName) = SplitQualifiedIdentifier(typeNameMemory);
            var type = new QualifiedType(containingNamespace, typeName);
            QualifiedMember member = memberNameValue is not null ? new QualifiedMember(type, memberNameValue) : default(QualifiedMember);

[Copilot]

Same nullable flow issue here: SplitQualifiedIdentifier returns a non-null string, but you deconstruct into string? typeName and then pass it to QualifiedType, which may produce nullable warnings. Use a non-null string local (or apply a null-forgiving operator if truly intended).

This issue also appears on line 89 of the same file.

Suggested change

	(ImmutableArray<string> containingNamespace, string? typeName) = SplitQualifiedIdentifier(typeNameMemory);
	(ImmutableArray<string> containingNamespace, string typeName) = SplitQualifiedIdentifier(typeNameMemory);

[Copilot]

using Microsoft.VisualStudio.Threading.Analyzers; is redundant here because the test project already defines global using Microsoft.VisualStudio.Threading.Analyzers; in Usings.cs. Keeping both can cause unnecessary-using style diagnostics in some configurations.

Suggested change

using Microsoft.VisualStudio.Threading.Analyzers;