Language server robustness fix. (#3607)

* Language server robustness fix.

* Allow parameter name to be the same as its type.

* fix

* Fix test.

7 files changed, 48 insertions, 20 deletions

diff --git a/source/slang/slang-ast-iterator.h b/source/slang/slang-ast-iterator.h
index fc6f321e3..2b6a2d3e2 100644
--- a/source/slang/slang-ast-iterator.h
+++ b/source/slang/slang-ast-iterator.h
@@ -479,6 +479,8 @@ void ASTIterator<CallbackFunc, FilterFunc>::visitDecl(DeclBase* decl)
         {
             visitDecl(member);
         }
+        if (auto aggTypeDecl = as<AggTypeDecl>(decl))
+            visitExpr(aggTypeDecl->wrappedType.exp);
     }
     for (auto modifier : decl->modifiers)
     {
diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 1c964ab88..28db66c45 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -7665,11 +7665,16 @@ namespace Slang
     {
         // Create a new sub-scope to wire the module
         // into our lookup chain.
+        if (!fileDecl)
+            return;
         addSiblingScopeForContainerDecl(getASTBuilder(), scope, fileDecl);
     }
 
     void SemanticsVisitor::importModuleIntoScope(Scope* scope, ModuleDecl* moduleDecl)
     {
+        if (!moduleDecl)
+            return;
+
         // If we've imported this one already, then
         // skip the step where we modify the current scope.
         auto& importedModulesList = getShared()->importedModulesList;
diff --git a/source/slang/slang-language-server-ast-lookup.cpp b/source/slang/slang-language-server-ast-lookup.cpp
index 13db8af18..755805b51 100644
--- a/source/slang/slang-language-server-ast-lookup.cpp
+++ b/source/slang/slang-language-server-ast-lookup.cpp
@@ -752,6 +752,12 @@ bool _findAstNodeImpl(ASTLookupContext& context, SyntaxNode* node)
                         return true;
                 }
             }
+            if (auto aggTypeDecl = as<AggTypeDecl>(container))
+            {
+                ASTLookupExprVisitor visitor(&context);
+                if (visitor.dispatchIfNotNull(aggTypeDecl->wrappedType.exp))
+                    return true;
+            }
         }
     }
     return false;
diff --git a/source/slang/slang-parser.cpp b/source/slang/slang-parser.cpp
index b208e1098..ad4e65bf2 100644
--- a/source/slang/slang-parser.cpp
+++ b/source/slang/slang-parser.cpp
@@ -105,7 +105,8 @@ namespace Slang
         int sameTokenPeekedTimes = 0;
 
         Scope* outerScope = nullptr;
-        Scope* currentScope = nullptr;
+        Scope* currentLookupScope = nullptr; // Scope where expr lookup should initiate from.
+        Scope* currentScope = nullptr; // Scope where new decl definitions should be inserted into.
         ModuleDecl* currentModule = nullptr;
 
         bool hasSeenCompletionToken = false;
@@ -126,20 +127,20 @@ namespace Slang
         {
             node->loc = tokenReader.peekLoc();
         }
-        void PushScope(ContainerDecl* containerDecl)
+
+        void resetLookupScope()
         {
-            // TODO(JS):
-            // 
-            // Previously Scope was ref counted. This meant that if a scope was pushed, but not used when popped
-            // it's memory would be freed.
-            //
-            // Here the memory is consumed and will not be freed until the astBuilder goes out of scope.
+            currentLookupScope = currentScope;
+        }
 
+        void PushScope(ContainerDecl* containerDecl)
+        {
             Scope* newScope = astBuilder->create<Scope>();
             newScope->containerDecl = containerDecl;
             newScope->parent = currentScope;
             currentScope = newScope;
             containerDecl->ownedScope = newScope;
+            resetLookupScope();
         }
 
         void pushScopeAndSetParent(ContainerDecl* containerDecl)
@@ -151,6 +152,7 @@ namespace Slang
         void PopScope()
         {
             currentScope = currentScope->parent;
+            resetLookupScope();
         }
 
         ModuleDecl* getCurrentModuleDecl()
@@ -2554,7 +2556,7 @@ namespace Slang
         Token typeName = parser->ReadToken(TokenType::Identifier);
 
         auto basicType = parser->astBuilder->create<VarExpr>();
-        basicType->scope = parser->currentScope;
+        basicType->scope = parser->currentLookupScope;
         basicType->loc = typeName.loc;
         basicType->name = typeName.getNameOrNull();
 
@@ -5591,9 +5593,9 @@ namespace Slang
     {
         ParamDecl* parameter = astBuilder->create<ParamDecl>();
         parameter->modifiers = ParseModifiers(this);
-
+        currentLookupScope = currentScope->parent;
         _parseTraditionalParamDeclCommonBase(this, parameter, kDeclaratorParseOption_AllowEmpty);
-
+        resetLookupScope();
         return parameter;
     }
 
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 498dc67f5..a1627286d 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -3302,22 +3302,33 @@ RefPtr<Module> Linkage::loadModule(
         return nullptr;
     }
 
-    loadParsedModule(
-        frontEndReq,
-        translationUnit,
-        name,
-        filePathInfo);
-
+    try
+    {
+        loadParsedModule(
+            frontEndReq,
+            translationUnit,
+            name,
+            filePathInfo);
+    }
+    catch (const Slang::AbortCompilationException&)
+    {
+        // Something is fatally wrong, we should return nullptr.
+        module = nullptr;
+    }
     errorCountAfter = sink->getErrorCount();
 
     if (errorCountAfter != errorCountBefore && !isInLanguageServer())
     {
+        // If something is fatally wrong, we want to report
+        // the diagnostic even if we are in language server
+        // and processing a different module.
         _diagnoseErrorInImportedModule(sink);
         // Something went wrong during the parsing, so we should bail out.
         return nullptr;
     }
 
-    module->setPathInfo(filePathInfo);
+    if (module)
+        module->setPathInfo(filePathInfo);
     return module;
 }
 
diff --git a/tests/diagnostics/recursive-import.slang b/tests/diagnostics/recursive-import.slang
index b74e55be4..312c579cf 100644
--- a/tests/diagnostics/recursive-import.slang
+++ b/tests/diagnostics/recursive-import.slang
@@ -1,6 +1,7 @@
-//DIAGNOSTIC_TEST:SIMPLE:
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
 
 // A file that recursively imports itself
 // (including transitive cases) should be diagnosed.
 
+// CHECK: ([[#@LINE+1]]): error 38200
 import recursive_import_extra;
diff --git a/tests/language-feature/modules/error-in-nested-import/error-in-nested-import.slang b/tests/language-feature/modules/error-in-nested-import/error-in-nested-import.slang
index 2efa69121..b709b52b1 100644
--- a/tests/language-feature/modules/error-in-nested-import/error-in-nested-import.slang
+++ b/tests/language-feature/modules/error-in-nested-import/error-in-nested-import.slang
@@ -1,6 +1,7 @@
 // error-in-nested-import.slang
-//DIAGNOSTIC_TEST:SIMPLE:
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
 
+// CHECK: ([[#@LINE+1]]): error
 import a;
 
 int main()