Overloaded name lookup fix (#2199)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Fix for overloaded name lookup.

* Small improvements.

7 files changed, 92 insertions, 68 deletions

diff --git a/source/slang/slang-lookup.cpp b/source/slang/slang-lookup.cpp
index e3093a3db..a77478ccb 100644
--- a/source/slang/slang-lookup.cpp
+++ b/source/slang/slang-lookup.cpp
@@ -752,6 +752,31 @@ static void _lookUpMembersInValue(
     return _lookUpMembersInType(astBuilder, name, valueType, request, ioResult, breadcrumbs);
 }
 
+// True if the declaration is of an overloadable variety  
+// (ie can have multiple definitions with the same name)
+// 
+// For example functions are overloadable, but variables are (typically) not.
+static bool _isDeclOverloadable(Decl* decl)
+{
+    // If it's a generic strip off, to get to inner decl type
+    while (auto genericDecl = as<GenericDecl>(decl))
+    {
+        decl = genericDecl->inner;
+    }
+
+    // TODO(JS): Do we need to special case around ConstructorDecl? or AccessorDecl?
+    // It seems not as they are both function-like and potentially overloadable
+
+    // If it's callable, it's a function-like and so overloadable 
+    if (auto callableDecl = as<CallableDecl>(decl))
+    {
+        SLANG_UNUSED(callableDecl);
+        return true;
+    }
+
+    return false;
+}
+
 static void _lookUpInScopes(
     ASTBuilder*             astBuilder,
     Name*                   name,
@@ -912,9 +937,16 @@ static void _lookUpInScopes(
 
         if (result.isValid())
         {
-            // If we've found a result in this scope, then there
+            // If it's overloaded or the decl we have is of an overloadable type then we just keep going
+            if (result.isOverloaded() || 
+                _isDeclOverloadable(result.item.declRef.getDecl()))
+            {
+                continue;
+            }
+
+            // If we've found a result in this scope (and it's not overloadable), then there
             // is no reason to look further up (for now).
-            return;
+            break;
         }
     }
 
diff --git a/tests/bugs/operator-overload.slang b/tests/bugs/operator-overload.slang
new file mode 100644
index 000000000..b70b9b987
--- /dev/null
+++ b/tests/bugs/operator-overload.slang
@@ -0,0 +1,31 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
+
+// Tests operator overloading works in user space.
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+struct Vec2d
+{   
+    float x, y;
+};
+
+Vec2d operator+(Vec2d a, Vec2d b)
+{
+    return {a.x + b.x, a.y + b.y};
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{    
+    int index = dispatchThreadID.x;
+    
+    Vec2d a = { 1, -index + 3 };
+    Vec2d b = { index - 4, index * index };
+    
+    Vec2d c = a + b;
+    
+    int r = int(c.x + c.y);
+    
+    outputBuffer[dispatchThreadID.x] = int(r);
+}
\ No newline at end of file
diff --git a/tests/bugs/operator-overload.slang.expected.txt b/tests/bugs/operator-overload.slang.expected.txt
new file mode 100644
index 000000000..c9fa0697e
--- /dev/null
+++ b/tests/bugs/operator-overload.slang.expected.txt
@@ -0,0 +1,4 @@
+0
+1
+4
+9
diff --git a/tests/bugs/shadowed-lookup.slang b/tests/bugs/shadowed-lookup.slang
new file mode 100644
index 000000000..ed4ab7893
--- /dev/null
+++ b/tests/bugs/shadowed-lookup.slang
@@ -0,0 +1,23 @@
+//TEST:COMPARE_COMPUTE_EX: -slang -compute
+
+RWStructuredBuffer<float> outputBuffer;
+
+struct SomeType
+{
+    float2x2 v;
+};
+
+float mul(SomeType a, float2 v) { return mul(a.v, v).x; }
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    uint tid = dispatchThreadID.x;
+
+    float inVal = float(tid);
+
+    float2 v = float2(inVal, inVal + 2);
+    SomeType t = { inVal + 1, 0, 1, 0 };
+    
+    outputBuffer[tid] = mul(t, v).x;
+} 
\ No newline at end of file
diff --git a/tests/bugs/shadowed-lookup.slang.expected.txt b/tests/bugs/shadowed-lookup.slang.expected.txt
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bugs/shadowed-lookup.slang.expected.txt
diff --git a/tests/current-bugs/mul-crash.slang b/tests/current-bugs/mul-crash.slang
deleted file mode 100644
index a5ee7e62c..000000000
--- a/tests/current-bugs/mul-crash.slang
+++ /dev/null
@@ -1,27 +0,0 @@
-//DISABLE_TEST:SIMPLE: -target hlsl -entry computeMain -stage compute
-
-// This test crashes when enabled, with a stack overrun. The crash happens when lowering into IR.
-// NOTE! That the code has a bug in that the mul function calls itself - so would exhaust the stack *when run*.
-// This exhausts the stack when compiling which shouldn't happen.
-
-RWStructuredBuffer<float> outputBuffer;
-
-struct SomeType
-{
-    float2x2 v;
-};
-
-float mul(SomeType a, float2 v) { return mul(a, v).x; }
-
-[numthreads(4, 1, 1)]
-void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
-{
-    uint tid = dispatchThreadID.x;
-
-    float inVal = float(tid);
-
-    float2 v = float2(inVal, inVal + 2);
-    SomeType t = { inVal + 1, 0, 1, 0 };
-    
-    outputBuffer[tid] = mul(t, v).x;
-} 
\ No newline at end of file
diff --git a/tests/experiments/generic/operator-overload.slang b/tests/experiments/generic/operator-overload.slang
deleted file mode 100644
index 590322171..000000000
--- a/tests/experiments/generic/operator-overload.slang
+++ /dev/null
@@ -1,39 +0,0 @@
-//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
-
-/* Test here is test out operator overloading. This may not be a feature
-that works in user code (it is used within the stdlib).
-
-This produces:
-.slang(10): error 30019: expected an expression of type 'Vec2d', got 'double'
-    return {a.x + b.x, a.y + b.y};
-
-Moreover...
-
-.slang(18): error 30019: expected an expression of type 'Vec2d', got 'int'
-    int a = 10 + 11;
-
-It's as if only this operator+ impl can now be seen.
-*/
-
-//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
-RWStructuredBuffer<int> outputBuffer;
-
-struct Vec2d
-{   
-    double x, y;
-};
-
-Vec2d operator+(Vec2d a, Vec2d b)
-{
-    return {a.x + b.x, a.y + b.y};
-}
-
-[numthreads(4, 1, 1)]
-void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
-{    
-    int index = dispatchThreadID.x;
-    
-    int a = 10 + 11;
-    
-    outputBuffer[dispatchThreadID.x] = int(v);
-}
\ No newline at end of file