Add Type resolution to Array expressions

This adds type inferencing and validation for arrays such as:

  let x: [i32, 5] = [1,2,3,4,5]
  ley y = [1,2,3];

It checks that each element is of a valid type and they line up correctly.
There needs to be some refactoring of the type resolution to handle the
array index expressions so this is a good save point for now.

Addresses: #27 #55

3 files changed, 180 insertions, 14 deletions

diff --git a/gcc/rust/analysis/rust-type-resolution.cc b/gcc/rust/analysis/rust-type-resolution.cc
index 707e0e8..aa2ea18 100644
--- a/gcc/rust/analysis/rust-type-resolution.cc
+++ b/gcc/rust/analysis/rust-type-resolution.cc
@@ -104,7 +104,13 @@ TypeResolution::typesAreCompatible (AST::Type *lhs, AST::Type *rhs,
     }
 
   AST::Type *val = NULL;
-  return scope.LookupType (lhsTypeStr, &val);
+  if (!scope.LookupType (lhsTypeStr, &val))
+    {
+      rust_error_at (locus, "Unknown type: %s", lhsTypeStr.c_str ());
+      return false;
+    }
+
+  return true;
 }
 
 bool
@@ -395,19 +401,112 @@ TypeResolution::visit (AST::CompoundAssignmentExpr &expr)
 void
 TypeResolution::visit (AST::GroupedExpr &expr)
 {}
-// void TypeResolution::visit(ArrayElems& elems) {}
+
 void
 TypeResolution::visit (AST::ArrayElemsValues &elems)
-{}
+{
+  // we need to generate the AST::ArrayType for this array init_expression
+  // we can get the size via get_num_values() but we need to ensure each element
+  // are type compatible
+
+  bool failed = false;
+  AST::Type *last_inferred_type = nullptr;
+  elems.iterate ([&] (AST::Expr *expr) mutable -> bool {
+    size_t before;
+    before = typeBuffer.size ();
+    expr->accept_vis (*this);
+    if (typeBuffer.size () <= before)
+      {
+	rust_error_at (expr->get_locus_slow (),
+		       "unable to determine element type");
+	return false;
+      }
+
+    AST::Type *inferedType = typeBuffer.back ();
+    typeBuffer.pop_back ();
+
+    if (last_inferred_type == nullptr)
+      last_inferred_type = inferedType;
+    else
+      {
+	if (!typesAreCompatible (last_inferred_type, inferedType,
+				 expr->get_locus_slow ()))
+	  {
+	    failed = true;
+	    return false;
+	  }
+      }
+
+    return true;
+  });
+
+  // nothing to do when its failed
+  if (failed)
+    return;
+
+  auto capacity
+    = new AST::LiteralExpr (std::to_string (elems.get_num_values ()),
+			    AST::Literal::INT,
+			    Linemap::predeclared_location ());
+  auto arrayType = new AST::ArrayType (last_inferred_type->clone_type (),
+				       std::unique_ptr<AST::Expr> (capacity),
+				       Linemap::predeclared_location ());
+  typeBuffer.push_back (arrayType);
+}
+
 void
 TypeResolution::visit (AST::ArrayElemsCopied &elems)
-{}
+{
+  printf ("ArrayElemsCopied: %s\n", elems.as_string ().c_str ());
+}
+
 void
 TypeResolution::visit (AST::ArrayExpr &expr)
-{}
+{
+  auto elements = expr.get_internal_elements ();
+  elements->accept_vis (*this);
+}
+
 void
 TypeResolution::visit (AST::ArrayIndexExpr &expr)
-{}
+{
+  printf ("ArrayIndexExpr: %s\n", expr.as_string ().c_str ());
+
+  auto before = typeBuffer.size ();
+  expr.get_array_expr ()->accept_vis (*this);
+  if (typeBuffer.size () <= before)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "unable to determine type for array index expression");
+      return;
+    }
+  AST::Type *array_expr_type = typeBuffer.back ();
+  typeBuffer.pop_back ();
+
+  before = typeBuffer.size ();
+  expr.get_index_expr ()->accept_vis (*this);
+  if (typeBuffer.size () <= before)
+    {
+      rust_error_at (expr.get_index_expr ()->get_locus_slow (),
+		     "unable to determine type for index expression");
+      return;
+    }
+
+  AST::Type *array_index_type = typeBuffer.back ();
+  typeBuffer.pop_back ();
+
+  printf ("Array expr type %s array index expr type: [%s]\n",
+	  array_expr_type->as_string ().c_str (),
+	  array_index_type->as_string ().c_str ());
+
+  // the the element type from the array_expr_type and it _must_ be an array
+  // TODO
+
+  // check the index_type should be an i32 which should really be
+  // more permissive
+  // TODO
+}
+
 void
 TypeResolution::visit (AST::TupleExpr &expr)
 {}
@@ -1015,7 +1114,7 @@ TypeResolution::visit (AST::LetStmt &stmt)
       return;
     }
 
-  AST::Type *inferedType = NULL;
+  AST::Type *inferedType = nullptr;
   if (stmt.has_init_expr ())
     {
       auto before = typeBuffer.size ();
@@ -1048,6 +1147,51 @@ TypeResolution::visit (AST::LetStmt &stmt)
 	  return;
 	}
     }
+  else if (stmt.has_type ())
+    {
+      auto before = typeComparisonBuffer.size ();
+      stmt.type->accept_vis (*this);
+      if (typeComparisonBuffer.size () <= before)
+	{
+	  rust_error_at (stmt.locus, "failed to understand type for lhs");
+	  return;
+	}
+      auto typeString = typeComparisonBuffer.back ();
+      typeComparisonBuffer.pop_back ();
+
+      AST::Type *val = NULL;
+      if (!scope.LookupType (typeString, &val))
+	{
+	  rust_error_at (stmt.locus, "LetStmt has unknown type: %s",
+			 stmt.type->as_string ().c_str ());
+	  return;
+	}
+    }
+  else if (inferedType != nullptr)
+    {
+      auto before = typeComparisonBuffer.size ();
+      inferedType->accept_vis (*this);
+      if (typeComparisonBuffer.size () <= before)
+	{
+	  rust_error_at (stmt.locus, "failed to understand type for lhs");
+	  return;
+	}
+      auto typeString = typeComparisonBuffer.back ();
+      typeComparisonBuffer.pop_back ();
+
+      AST::Type *val = NULL;
+      if (!scope.LookupType (typeString, &val))
+	{
+	  rust_error_at (stmt.locus, "Inferred unknown type: %s",
+			 inferedType->as_string ().c_str ());
+	  return;
+	}
+    }
+  else
+    {
+      rust_fatal_error (stmt.locus, "Failed to determine any type for LetStmt");
+      return;
+    }
 
   // ensure the decl has the type set for compilation later on
   if (!stmt.has_type ())
@@ -1115,9 +1259,13 @@ TypeResolution::visit (AST::RawPointerType &type)
 void
 TypeResolution::visit (AST::ReferenceType &type)
 {}
+
 void
 TypeResolution::visit (AST::ArrayType &type)
-{}
+{
+  typeComparisonBuffer.push_back (type.get_element_type ()->as_string ());
+}
+
 void
 TypeResolution::visit (AST::SliceType &type)
 {}
diff --git a/gcc/rust/ast/rust-expr.h b/gcc/rust/ast/rust-expr.h
index fd6913f..d3e7cbd 100644
--- a/gcc/rust/ast/rust-expr.h
+++ b/gcc/rust/ast/rust-expr.h
@@ -928,6 +928,17 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  size_t get_num_values () const { return values.size (); }
+
+  void iterate (std::function<bool (Expr *)> cb)
+  {
+    for (auto it = values.begin (); it != values.end (); it++)
+      {
+	if (!cb ((*it).get ()))
+	  return;
+      }
+  }
+
 protected:
   ArrayElemsValues *clone_array_elems_impl () const override
   {
@@ -1037,6 +1048,8 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  ArrayElems *get_internal_elements () { return internal_elements.get (); };
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
@@ -1100,6 +1113,9 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  Expr *get_array_expr () { return array_expr.get (); }
+  Expr *get_index_expr () { return index_expr.get (); }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
diff --git a/gcc/rust/ast/rust-type.h b/gcc/rust/ast/rust-type.h
index b396a44..301b664 100644
--- a/gcc/rust/ast/rust-type.h
+++ b/gcc/rust/ast/rust-type.h
@@ -60,7 +60,7 @@ class ImplTraitType : public Type
 {
   // TypeParamBounds type_param_bounds;
   // inlined form
-  std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds;
+  std::vector<std::unique_ptr<TypeParamBound> > type_param_bounds;
 
   Location locus;
 
@@ -74,7 +74,7 @@ protected:
 
 public:
   ImplTraitType (
-    std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds,
+    std::vector<std::unique_ptr<TypeParamBound> > type_param_bounds,
     Location locus)
     : type_param_bounds (std::move (type_param_bounds)), locus (locus)
   {}
@@ -115,7 +115,7 @@ class TraitObjectType : public Type
 {
   bool has_dyn;
   // TypeParamBounds type_param_bounds;
-  std::vector<std::unique_ptr<TypeParamBound>>
+  std::vector<std::unique_ptr<TypeParamBound> >
     type_param_bounds; // inlined form
 
   Location locus;
@@ -130,7 +130,7 @@ protected:
 
 public:
   TraitObjectType (
-    std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds,
+    std::vector<std::unique_ptr<TypeParamBound> > type_param_bounds,
     Location locus, bool is_dyn_dispatch = false)
     : has_dyn (is_dyn_dispatch),
       type_param_bounds (std::move (type_param_bounds)), locus (locus)
@@ -318,14 +318,14 @@ class TypePath; // definition moved to "rust-path.h"
  * specific order */
 class TupleType : public TypeNoBounds
 {
-  std::vector<std::unique_ptr<Type>> elems;
+  std::vector<std::unique_ptr<Type> > elems;
   Location locus;
 
 public:
   // Returns whether the tuple type is the unit type, i.e. has no elements.
   bool is_unit_type () const { return elems.empty (); }
 
-  TupleType (std::vector<std::unique_ptr<Type>> elems, Location locus)
+  TupleType (std::vector<std::unique_ptr<Type> > elems, Location locus)
     : elems (std::move (elems)), locus (locus)
   {}
 
@@ -574,6 +574,8 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  Type *get_element_type () { return elem_type.get (); }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */