From 013bcf28da22fd569154bd9f98368e670fbeb873 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Thu, 25 Jan 2024 17:47:40 -0800
Subject: Fixes for `module` and `include`. (#3519)

* Fix type checking of enum cases.

* Allow decl to have same name as module.

---------

Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/slang-check-decl.cpp                | 10 ++++++++++
 source/slang/slang-check-overload.cpp            |  6 ++++++
 tests/language-feature/modules/module-name.slang | 24 ++++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 tests/language-feature/modules/module-name.slang

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 0df9619b6..fe4a7d64c 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -528,6 +528,7 @@ namespace Slang
         }
         else if( auto enumCaseDeclRef = declRef.as<EnumCaseDecl>() )
         {
+            sema->ensureDecl(declRef.declRefBase, DeclCheckState::Checked);
             QualType qualType;
             qualType.type = getType(astBuilder, enumCaseDeclRef);
             qualType.isLeftValue = false;
@@ -5117,6 +5118,8 @@ namespace Slang
         // TODO: Do we need/want to support generic cases some day?
         auto parentEnumDecl = as<EnumDecl>(decl->parentDecl);
         SLANG_ASSERT(parentEnumDecl);
+        
+        decl->type.type = DeclRefType::create(m_astBuilder, makeDeclRef(parentEnumDecl));
 
         // The tag type should have already been set by
         // the surrounding `enum` declaration.
@@ -5852,6 +5855,13 @@ namespace Slang
             }
         }
 
+        if (as<ModuleDeclarationDecl>(oldDecl) || as<ModuleDeclarationDecl>(newDecl))
+        {
+            // It is allowed to have a decl whose name is the same as the module.
+            return SLANG_OK;
+        }
+
+
         // For all other flavors of declaration, we do not
         // allow duplicate declarations with the same name.
         //
diff --git a/source/slang/slang-check-overload.cpp b/source/slang/slang-check-overload.cpp
index 2912a79b0..37c92a317 100644
--- a/source/slang/slang-check-overload.cpp
+++ b/source/slang/slang-check-overload.cpp
@@ -992,6 +992,12 @@ namespace Slang
         if(leftIsInterfaceRequirement != rightIsInterfaceRequirement)
             return int(leftIsInterfaceRequirement) - int(rightIsInterfaceRequirement);
 
+        // Any decl is strictly better than a module decl.
+        bool leftIsModule = (as<ModuleDeclarationDecl>(left.declRef) != nullptr);
+        bool rightIsModule = (as<ModuleDeclarationDecl>(right.declRef) != nullptr);
+        if(leftIsModule != rightIsModule)
+            return int(rightIsModule) - int(leftIsModule);
+
         // If both are interface requirements, prefer to more derived interface.
         if (leftIsInterfaceRequirement && rightIsInterfaceRequirement)
         {
diff --git a/tests/language-feature/modules/module-name.slang b/tests/language-feature/modules/module-name.slang
new file mode 100644
index 000000000..32e8c70d2
--- /dev/null
+++ b/tests/language-feature/modules/module-name.slang
@@ -0,0 +1,24 @@
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK): -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK): -vk -shaderobj -output-using-type
+
+// Test that decls with the same name as the module are allowed.
+
+module MyModule;
+
+struct MyModule
+{
+    int doThing()
+    {
+        return 1;
+    }
+}
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=output
+RWStructuredBuffer<int> output;
+
+void computeMain()
+{
+    MyModule m;
+    output[0] = m.doThing();
+    // CHECK: 1
+}
-- 
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