Create rule S6675: Trace.WriteLineIf should not be used with TraceSwitch levels (#2575)

rules/S6675/csharp/metadata.json

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+{
+}

rules/S6675/csharp/rule.adoc

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+include::../rule.adoc[]

rules/S6675/metadata.json

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+{
+  "title": "\"Trace.WriteLineIf\" should not be used with \"TraceSwitch\" levels",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "confusing",
+    "clumsy",
+    "logging"
+  ],
+  "extra": {
+  },
+  "defaultSeverity": "Minor",
+  "ruleSpecification": "RSPEC-6675",
+  "sqKey": "S6675",
+  "scope": "Main",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "targeted"
+}

rules/S6675/rspecator.adoc

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+ifdef::env-github,rspecator-view[]
+
+'''
+== Implementation Specification
+(visible only on this page)
+
+=== Message
+
+Use `Trace.WriteXXX` instead.
+
+=== Highlighting
+
+`Trace.WriteLineIf(switch.TraceXXX, ...)`
+
+'''
+== Comments And Links
+(visible only on this page)
+
+endif::env-github,rspecator-view[]

rules/S6675/rule.adoc

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+== Why is this an issue?
+
+The https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.writelineif[`Trace.WriteLineIf` Method] from the https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace[`System.Diagnostic.Trace`] facility writes a trace if the condition passed as the first parameter is `true`.
+
+https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.traceswitch[`TraceSwitch`] allows trace control via `bool` properties for each relevant https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.tracelevel[`TraceLevel`], such as https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.traceswitch.traceerror[`TraceSwitch.TraceError`].
+
+Using `Trace.WriteLineIf` with such properties should be avoided since it can lead to misinterpretation and produce confusion. 
+
+In particular, `Trace.WriteLineIf` may appear as equivalent to the level-specific tracing methods provided by `Trace`, such as https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.traceerror[`Trace.Error`], but it is not.
+
+The difference is that `Trace.WriteLineIf(switch.TraceError, ...)` conditionally writes the trace, based on the switch, whereas `Trace.TraceError` always writes the trace, no matter whether `switch.TraceError` is `true` or `false`.
+
+Moreover, unlike `Trace.TraceError`, `Trace.WriteLineIf(switch.TraceError, ...)` would behave like `Trace.WriteLine(...)` when `switch.TraceError` is `true`, writing unfiltered to the underlying trace listeners and not categorizing the log entry by level, as described more in detail in S6670.
+
+== How to fix it
+
+The fix depends on the intent behind the use of https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.traceswitch[`TraceSwitch`] levels with https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.writelineif[`Trace.WriteLineIf`].
+
+If it is *trace categorization*, level-specific tracing methods, such as https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.traceerror[`Trace.TraceError`] or https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.tracewarning[`Trace.TraceWarning]`, should be used instead.
+
+If it is *trace filtering*, https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.tracesource[`TraceSource`] should be used instead.
+
+If it is *log filtering*, `Trace` should be replaced by logging APIs, such as the https://learn.microsoft.com/en-us/dotnet/core/diagnostics/logging-tracing#net-logging-apis[`ILogger` API].
+
+Modern logging APIs are also more suitable than `Trace` when https://learn.microsoft.com/en-us/dotnet/core/extensions/high-performance-logging[high-performance logging] is required.
+
+== Resources
+
+=== Documentation
+
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.writelineif[`Trace.WriteLineIf` Method]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.traceswitch[`TraceSwitch`]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.tracesource[`TraceSource`]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.trace.writeline[`Trace.WriteLine` Method]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/core/extensions/high-performance-logging[High-performance logging in .NET]
+
+=== Articles & blog posts
+
+* StackOverflow - https://stackoverflow.com/a/5118040[Difference between Trace.WriteLineIf and Trace.Error]
+* StackOverflow - https://stackoverflow.com/a/3691841[Difference between TraceSwitch and SourceSwitch]
+* InfoSupport Blogs - https://blogs.infosupport.com/please-be-careful-when-using-trace-writelineif/[Please be careful when using Trace.WriteLineIf()]
+
+include::rspecator.adoc[]