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Add Type resolution to Array expressions
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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
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@philberty
philberty committed Dec 1, 2020
1 parent 37560f9 commit 886b230
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Showing 3 changed files with 180 additions and 14 deletions.
164 changes: 156 additions & 8 deletions gcc/rust/analysis/rust-type-resolution.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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)
{}
Expand Down Expand Up @@ -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 ();
Expand Down Expand Up @@ -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 ())
Expand Down Expand Up @@ -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)
{}
Expand Down
16 changes: 16 additions & 0 deletions gcc/rust/ast/rust-expr.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -928,6 +928,17 @@ class ArrayElemsValues : public ArrayElems

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
{
Expand Down Expand Up @@ -1037,6 +1048,8 @@ class ArrayExpr : public ExprWithoutBlock

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 */
Expand Down Expand Up @@ -1100,6 +1113,9 @@ class ArrayIndexExpr : public ExprWithoutBlock

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 */
Expand Down
14 changes: 8 additions & 6 deletions gcc/rust/ast/rust-type.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand All @@ -74,7 +74,7 @@ class ImplTraitType : public Type

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)
{}
Expand Down Expand Up @@ -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;
Expand All @@ -130,7 +130,7 @@ class TraitObjectType : public Type

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)
Expand Down Expand Up @@ -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)
{}

Expand Down Expand Up @@ -574,6 +574,8 @@ class ArrayType : public TypeNoBounds

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 */
Expand Down

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