Check for re-import at translation-unit level

Previously the code checked for a duplicate `#import` using a data structure attached to the compile request, but this would fail for nested imports.
It also wouldn't work for a combination of `#import` and `__import`.

This change makes it so that we instead track a set of already-imported modules in the semantic checking visitor, which is instantiated once per translation unit.
We also key this set on the actual module (AST) imported, rather than on path/name/whatever, so hopefully it will be robust to the same thing getting imported multiple ways.

1 files changed, 3 insertions, 4 deletions

diff --git a/source/slang/preprocessor.h b/source/slang/preprocessor.h
index ebeb810a0..d23b19773 100644
--- a/source/slang/preprocessor.h
+++ b/source/slang/preprocessor.h
@@ -7,9 +7,9 @@
 
 namespace Slang {
 
-class CompileRequest;
 class DiagnosticSink;
 class ProgramSyntaxNode;
+class TranslationUnitRequest;
 
 enum class IncludeResult
 {
@@ -35,9 +35,8 @@ TokenList preprocessSource(
     String const&               fileName,
     DiagnosticSink*             sink,
     IncludeHandler*             includeHandler,
-     Dictionary<String, String> defines,
-    ProgramSyntaxNode*          syntax,
-    CompileRequest*             compileRequest);
+    Dictionary<String, String>  defines,
+    TranslationUnitRequest*     translationUnit);
 
 } // namespace Slang