Fix S1144: Do not keep references to all type symbols

[valhristov]

Description

We keep references to all found type symbols in order to be able to look for usages a second time when the compilation ends and report for unused internal symbols. These references put huge memory pressure and the analysis is very slow on large projects which do not have InternalsVisibleTo attributes.

Related bug report #2154

Repro steps

• Create a project with many (~1000) large classes, containing internal members.
• Make sure there is no InternalsVisibleTo attributes in the project.
• Analyze with S1144 enabled.

Expected behavior

The analysis takes reasonable amount of time. For example, on a project with 1000 classes with complex syntax trees (about 300 loc) the analysis should take about 2min or less. The used memory from the compiler is reasonable (on the example project, no more than 1GB).

Actual behavior

Analysis takes 20+ minutes on the aforementioned project. On larger projects the analysis takes much more (see #2154) and the used memory during the compilation is >2GB.

Known workarounds

• Disable S1144
• Add InternalsVisibleTo attribute

Related information

• SonarC# 7.9