c# - Get a list of referenced Types within a project with Roslyn -

i want list of used types in project, example:

var x = 1; var y = x.tostring().gettype(); 

the code should return system.int32, system.string, system.type.

what have freaking slow... each file (syntax tree), following:

var root = await syntaxtree.getrootasync(); var nodes = root.descendantnodes(n => true);  if (nodes != null) {     var syntaxnodes = nodes syntaxnode[] ?? nodes.toarray();      // identifiernamesyntax:     //  - var keyword     //  - identifiers of kind (including type names)     var namedtypes = syntaxnodes         .oftype<identifiernamesyntax>()         .select(id => this.compilation                   .getsemanticmodel(id.syntaxtree)                   .getsymbolinfo(id)                   .symbol)         .oftype<inamedtypesymbol>()         .toarray();      // add found types list     this.addrange(namedtypes);      // expressionsyntax:     //  - method calls     //  - property uses     //  - field uses     //  - kinds of composite expressions     var expressionsyntaxs = syntaxnodes         .oftype<expressionsyntax>()         .tolist();      var typesymbols = new list<itypesymbol>();     (int index = 0; index < expressionsyntaxs.count; index++)     {         expressionsyntax ma = expressionsyntaxs[index];         typesymbols.add(this.compilation                     .getsemanticmodel(ma.syntaxtree)                     .gettypeinfo(ma)                     .type);     }      var expressiontypes = typesymbols         .oftype<inamedtypesymbol>()         .toarray();      // add found types list     this.addrange(expressiontypes); } 

motivation:

i making tool analyses project, , tells .net framework versions support given project (e.g. portable .net frameworks).

i hoped faster match set of used types set of available types framework, before compiling.

with small files code fast enough, , total amount of time less of compiling every possible framework... large files unacceptable.

is there way list of types in way acceptable?

so, i've learnt lesson: never assume immutable structure going cache of it's calculations because 2 calls return same result.

it true when method pure, return same structurally, doesn't have same instance.

my assumption lead me error: thinking this.compilation.getsemanticmodel(id.syntaxtree) return same instance of semantic model given syntaxtree... it's not true.

i changed code following, , blazing fast:

var root = await syntaxtree.getrootasync(); var nodes = root.descendantnodes(n => true);  var st = root.syntaxtree; var sm = this.compilation.getsemanticmodel(st);  if (nodes != null) {     var syntaxnodes = nodes syntaxnode[] ?? nodes.toarray();      // identifiernamesyntax:     //  - var keyword     //  - identifiers of kind (including type names)     var namedtypes = syntaxnodes         .oftype<identifiernamesyntax>()         .select(id => sm.getsymbolinfo(id).symbol)         .oftype<inamedtypesymbol>()         .toarray();      this.add(namedtypes);      // expressionsyntax:     //  - method calls     //  - property uses     //  - field uses     //  - kinds of composite expressions     var expressiontypes = syntaxnodes         .oftype<expressionsyntax>()         .select(ma => sm.gettypeinfo(ma).type)         .oftype<inamedtypesymbol>()         .toarray();      this.add(expressiontypes); }