3 files changed, 51 insertions, 1 deletions
diff --git a/src/ast/ast.cpp b/src/ast/ast.cpp
index b8e6d381..4c400a47 100644
--- a/src/ast/ast.cpp
+++ b/src/ast/ast.cpp
@@ -80,7 +80,29 @@ Impl Impl::make_concrete(const ::std::vector<TypeRef>& types) const
 
 ::rust::option<Impl&> Impl::matches(const Path& trait, const TypeRef& type)
 {
-    DEBUG("this = " << *this);
+    //DEBUG("this = " << *this);
+    
+    // 1. Check the type/trait counting parameters as wildcards (but flagging if one was seen)
+    //  > If that fails, just early return
+    int trait_match = m_trait.equal_no_generic(trait);
+    if( trait_match < 0 )
+        return ::rust::option<Impl&>();
+    DEBUG("Trait " << trait << " matches " << trait_match);
+    int type_match = m_type.equal_no_generic(type);
+    if( type_match < 0 )
+        return ::rust::option<Impl&>();
+    DEBUG("Type " << type << " matches " << type_match);
+    // 2. If a parameter was seen, do the more expensive generic checks
+    //  > Involves checking that parameters are valid
+    if( trait_match > 0 )
+    {
+        throw CompileError::Todo("Generic-ised match of impl trait");
+    }
+    if( type_match > 0 )
+    {
+        throw CompileError::Todo("Generic-ised match of impl type");
+    }
+    // 3. Return success
     
     if( m_params.ty_params().size() > 0 )
     {
diff --git a/src/ast/path.cpp b/src/ast/path.cpp
index 381685a9..7fa630f9 100644
--- a/src/ast/path.cpp
+++ b/src/ast/path.cpp
@@ -361,6 +361,31 @@ Path& Path::operator+=(const Path& other)
     return *this;
 }
 
+int Path::equal_no_generic(const Path& x) const
+{
+    if( m_class != x.m_class )
+        return -1;
+    if( m_crate != x.m_crate )
+        return -1;
+    
+    unsigned int i = 0;
+    for( const auto &e : m_nodes )
+    {
+        if( i >= x.m_nodes.size() )
+            return -1;
+        const auto& xe = x.m_nodes[i];
+        if( e.name() != xe.name() )
+            return -1;
+        
+        if( e.args().size() || xe.args().size() )
+            throw CompileError::Todo("Handle Path::equal_no_generic with generic");
+        
+        i ++;
+    }
+    
+    return 0;
+}
+
 Ordering Path::ord(const Path& x) const
 {
     Ordering rv;
diff --git a/src/ast/path.hpp b/src/ast/path.hpp
index 2355c88b..21d2dd51 100644
--- a/src/ast/path.hpp
+++ b/src/ast/path.hpp
@@ -264,6 +264,9 @@ public:
     PathNode& operator[](int idx) { if(idx>=0) return m_nodes[idx]; else return m_nodes[size()+idx]; }
     const PathNode& operator[](int idx) const { if(idx>=0) return m_nodes[idx]; else return m_nodes[size()+idx]; }
    
+    /// Returns 0 if paths are identical, 1 if TypeRef::TagArg is present in one, and -1 if a node differs
+    int equal_no_generic(const Path& x) const;
+    
     Ordering ord(const Path& x) const;
     bool operator==(const Path& x) const { return ord(x) == OrdEqual; }
     bool operator!=(const Path& x) const { return ord(x) != OrdEqual; }