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Expose source_info position -> SourceLocation helper. #1924

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Merged
copybara-service merged 1 commit into from
Apr 2, 2026
+110 −48
Merged

Expose source_info position -> SourceLocation helper. #1924

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58 changes: 10 additions & 48 deletions checker/internal/type_checker_impl.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,6 @@
#include "common/constant.h"
#include "common/decl.h"
#include "common/expr.h"
#include "common/source.h"
#include "common/type.h"
#include "common/type_kind.h"
#include "internal/status_macros.h"
Expand All @@ -66,43 +65,6 @@ std::string FormatCandidate(absl::Span<const std::string> qualifiers) {
return absl::StrJoin(qualifiers, ".");
}

SourceLocation ComputeSourceLocation(const Ast& ast, int64_t expr_id) {
const auto& source_info = ast.source_info();
auto iter = source_info.positions().find(expr_id);
if (iter == source_info.positions().end()) {
return SourceLocation{};
}
int32_t absolute_position = iter->second;
if (absolute_position < 0) {
return SourceLocation{};
}

// Find the first line offset that is greater than the absolute position.
int32_t line_idx = -1;
int32_t offset = 0;
for (int32_t i = 0; i < source_info.line_offsets().size(); ++i) {
int32_t next_offset = source_info.line_offsets()[i];
if (next_offset <= offset) {
// Line offset is not monotonically increasing, so line information is
// invalid.
return SourceLocation{};
}
if (absolute_position < next_offset) {
line_idx = i;
break;
}
offset = next_offset;
}

if (line_idx < 0 || line_idx >= source_info.line_offsets().size()) {
return SourceLocation{};
}

int32_t rel_position = absolute_position - offset;

return SourceLocation{line_idx + 1, rel_position};
}

// Flatten the type to the AST type representation to remove any lifecycle
// dependency between the type check environment and the AST.
//
Expand Down Expand Up @@ -362,23 +324,23 @@ class ResolveVisitor : public AstVisitorBase {

void ReportMissingReference(const Expr& expr, absl::string_view name) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr.id()),
ast_->ComputeSourceLocation(expr.id()),
absl::StrCat("undeclared reference to '", name, "' (in container '",
container_, "')")));
}

void ReportUndefinedField(int64_t expr_id, absl::string_view field_name,
absl::string_view struct_name) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr_id),
ast_->ComputeSourceLocation(expr_id),
absl::StrCat("undefined field '", field_name, "' not found in struct '",
struct_name, "'")));
}

void ReportTypeMismatch(int64_t expr_id, const Type& expected,
const Type& actual) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr_id),
ast_->ComputeSourceLocation(expr_id),
absl::StrCat("expected type '",
FormatTypeName(inference_context_->FinalizeType(expected)),
"' but found '",
Expand Down Expand Up @@ -408,7 +370,7 @@ class ResolveVisitor : public AstVisitorBase {
}
if (!inference_context_->IsAssignable(value_type, field_type)) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, field.id()),
ast_->ComputeSourceLocation(field.id()),
absl::StrCat(
"expected type of field '", field_info->name(), "' is '",
FormatTypeName(inference_context_->FinalizeType(field_type)),
Expand Down Expand Up @@ -553,7 +515,7 @@ void ResolveVisitor::PostVisitConst(const Expr& expr,
break;
default:
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr.id()),
ast_->ComputeSourceLocation(expr.id()),
absl::StrCat("unsupported constant type: ",
constant.kind().index())));
types_[&expr] = ErrorType();
Expand Down Expand Up @@ -605,7 +567,7 @@ void ResolveVisitor::PostVisitMap(const Expr& expr, const MapExpr& map) {
// To match the Go implementation, we just warn here, but in the future
// we should consider making this an error.
ReportIssue(TypeCheckIssue(
Severity::kWarning, ComputeSourceLocation(*ast_, key->id()),
Severity::kWarning, ast_->ComputeSourceLocation(key->id()),
absl::StrCat(
"unsupported map key type: ",
FormatTypeName(inference_context_->FinalizeType(key_type)))));
Expand Down Expand Up @@ -711,7 +673,7 @@ void ResolveVisitor::PostVisitStruct(const Expr& expr,
if (resolved_type.kind() != TypeKind::kStruct &&
!IsWellKnownMessageType(resolved_name)) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr.id()),
ast_->ComputeSourceLocation(expr.id()),
absl::StrCat("type '", resolved_name,
"' does not support message creation")));
types_[&expr] = ErrorType();
Expand Down Expand Up @@ -862,7 +824,7 @@ void ResolveVisitor::PostVisitComprehensionSubexpression(
break;
default:
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, comprehension.iter_range().id()),
ast_->ComputeSourceLocation(comprehension.iter_range().id()),
absl::StrCat(
"expression of type '",
FormatTypeName(inference_context_->FinalizeType(range_type)),
Expand Down Expand Up @@ -933,7 +895,7 @@ void ResolveVisitor::ResolveFunctionOverloads(const Expr& expr,

if (!resolution.has_value()) {
ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, expr.id()),
ast_->ComputeSourceLocation(expr.id()),
absl::StrCat("found no matching overload for '", decl.name(),
"' applied to '(",
absl::StrJoin(arg_types, ", ",
Expand Down Expand Up @@ -1133,7 +1095,7 @@ absl::optional<Type> ResolveVisitor::CheckFieldType(int64_t id,
}

ReportIssue(TypeCheckIssue::CreateError(
ComputeSourceLocation(*ast_, id),
ast_->ComputeSourceLocation(id),
absl::StrCat(
"expression of type '",
FormatTypeName(inference_context_->FinalizeType(operand_type)),
Expand Down
2 changes: 2 additions & 0 deletions common/BUILD
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ cc_library(
hdrs = ["ast.h"],
deps = [
":expr",
":source",
"//common/ast:metadata",
"@com_google_absl//absl/base:no_destructor",
"@com_google_absl//absl/base:nullability",
Expand All @@ -39,6 +40,7 @@ cc_test(
deps = [
":ast",
":expr",
":source",
"//internal:testing",
"@com_google_absl//absl/container:flat_hash_map",
],
Expand Down
38 changes: 38 additions & 0 deletions common/ast.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#include "absl/base/no_destructor.h"
#include "absl/base/nullability.h"
#include "common/ast/metadata.h"
#include "common/source.h"

namespace cel {
namespace {
Expand Down Expand Up @@ -57,4 +58,41 @@ const Reference* absl_nullable Ast::GetReference(int64_t expr_id) const {
return &iter->second;
}

SourceLocation Ast::ComputeSourceLocation(int64_t expr_id) const {
const auto& source_info = this->source_info();
auto iter = source_info.positions().find(expr_id);
if (iter == source_info.positions().end()) {
return SourceLocation{};
}
int32_t absolute_position = iter->second;
if (absolute_position < 0) {
return SourceLocation{};
}

// Find the first line offset that is greater than the absolute position.
int32_t line_idx = -1;
int32_t offset = 0;
for (int32_t i = 0; i < source_info.line_offsets().size(); ++i) {
int32_t next_offset = source_info.line_offsets()[i];
if (next_offset <= offset) {
// Line offset is not monotonically increasing, so line information is
// invalid.
return SourceLocation{};
}
if (absolute_position < next_offset) {
line_idx = i;
break;
}
offset = next_offset;
}

if (line_idx < 0 || line_idx >= source_info.line_offsets().size()) {
return SourceLocation{};
}

int32_t rel_position = absolute_position - offset;

return SourceLocation{line_idx + 1, rel_position};
}

} // namespace cel
8 changes: 8 additions & 0 deletions common/ast.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#include "absl/strings/string_view.h"
#include "common/ast/metadata.h" // IWYU pragma: export
#include "common/expr.h"
#include "common/source.h"

namespace cel {

Expand Down Expand Up @@ -135,6 +136,13 @@ class Ast final {
expr_version_ = expr_version;
}

// Computes the source location (line and column) for the given expression id
// from the source info (which stores absolute positions).
//
// Returns a default (empty) source location if the expression id is not found
// or the source info is not populated correctly.
SourceLocation ComputeSourceLocation(int64_t expr_id) const;

private:
Expr root_expr_;
SourceInfo source_info_;
Expand Down
52 changes: 52 additions & 0 deletions common/ast_test.cc
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Expand Up @@ -18,6 +18,7 @@

#include "absl/container/flat_hash_map.h"
#include "common/expr.h"
#include "common/source.h"
#include "internal/testing.h"

namespace cel {
Expand Down Expand Up @@ -132,5 +133,56 @@ TEST(AstImpl, CheckedExprDeepCopy) {
EXPECT_EQ(ast.source_info().syntax_version(), "1.0");
}

TEST(AstImpl, ComputeSourceLocation) {
SourceInfo source_info;
source_info.set_line_offsets({10, 20, 30});
source_info.mutable_positions()[1] = 0; // Start of first line
source_info.mutable_positions()[2] = 5; // Middle of first line
source_info.mutable_positions()[3] = 10; // ...
source_info.mutable_positions()[4] = 15;
source_info.mutable_positions()[5] = 20;
source_info.mutable_positions()[6] = 25;

Ast ast(Expr{}, std::move(source_info));

EXPECT_EQ(ast.ComputeSourceLocation(1), (SourceLocation{1, 0}));
EXPECT_EQ(ast.ComputeSourceLocation(2), (SourceLocation{1, 5}));
EXPECT_EQ(ast.ComputeSourceLocation(3), (SourceLocation{2, 0}));
EXPECT_EQ(ast.ComputeSourceLocation(4), (SourceLocation{2, 5}));
EXPECT_EQ(ast.ComputeSourceLocation(5), (SourceLocation{3, 0}));
EXPECT_EQ(ast.ComputeSourceLocation(6), (SourceLocation{3, 5}));
}

TEST(AstImpl, ComputeSourceLocationFailures) {
SourceInfo source_info;
source_info.set_line_offsets({10, 20});
source_info.mutable_positions()[1] = -1; // Negative position
source_info.mutable_positions()[2] = 25; // Beyond last line offset
// ID 3 is missing

Ast ast;
ast.mutable_source_info() = std::move(source_info);

EXPECT_EQ(ast.ComputeSourceLocation(1), SourceLocation{});
EXPECT_EQ(ast.ComputeSourceLocation(2), SourceLocation{});
EXPECT_EQ(ast.ComputeSourceLocation(3), SourceLocation{});
}

TEST(AstImpl, ComputeSourceLocationInvalidLineOffsets) {
{
// Empty line offsets
Ast ast;
EXPECT_EQ(ast.ComputeSourceLocation(1), SourceLocation{});
}
{
// Non-monotonic
SourceInfo source_info;
source_info.set_line_offsets({10, 5});
source_info.mutable_positions()[1] = 12;
Ast ast(Expr{}, std::move(source_info));
EXPECT_EQ(ast.ComputeSourceLocation(1), SourceLocation{});
}
}

} // namespace
} // namespace cel