Location, error formatting and stack trace improvements (#59)

* Location, error formatting and stack trace improvements

* Static context for AST nodes
* Thunks no longer need `name`
* Prototype for showing snippets in error messages (old format still
available)
* Use ast.Function to represent methods and local function sugar.
* Change tests so that the error output is pretty

ast/ast.go

@@ -30,10 +30,14 @@ type Identifiers []Identifier
 
 // ---------------------------------------------------------------------------
 
+type Context *string
+
 type Node interface {
+	Context() Context
 	Loc() *LocationRange
 	FreeVariables() Identifiers
 	SetFreeVariables(Identifiers)
+	SetContext(Context)
 }
 type Nodes []Node
 
@@ -41,6 +45,7 @@ type Nodes []Node
 
 type NodeBase struct {
 	loc           LocationRange
+	context       Context
 	freeVariables Identifiers
 }
 
@@ -70,6 +75,14 @@ func (n *NodeBase) SetFreeVariables(idents Identifiers) {
 	n.freeVariables = idents
 }
 
+func (n *NodeBase) Context() Context {
+	return n.context
+}
+
+func (n *NodeBase) SetContext(context Context) {
+	n.context = context
+}
+
 // ---------------------------------------------------------------------------
 
 type IfSpec struct {
@@ -356,11 +369,9 @@ type Slice struct {
 
 // LocalBind is a helper struct for astLocal
 type LocalBind struct {
-	Variable      Identifier
-	Body          Node
-	FunctionSugar bool
-	Params        *Parameters // if functionSugar is true
-	TrailingComma bool
+	Variable Identifier
+	Body     Node
+	Fun      *Function
 }
 type LocalBinds []LocalBind
 
@@ -439,7 +450,8 @@ type ObjectField struct {
 	Hide          ObjectFieldHide // (ignore if kind != astObjectField*)
 	SuperSugar    bool            // +:  (ignore if kind != astObjectField*)
 	MethodSugar   bool            // f(x, y, z): ...  (ignore if kind  == astObjectAssert)
-	Expr1         Node            // Not in scope of the object
+	Method        *Function
+	Expr1         Node // Not in scope of the object
 	Id            *Identifier
 	Params        *Parameters // If methodSugar == true then holds the params.
 	TrailingComma bool        // If methodSugar == true then remembers the trailing comma
@@ -448,12 +460,8 @@ type ObjectField struct {
 
 // TODO(jbeda): Add the remaining constructor helpers here
 
-func ObjectFieldLocal(methodSugar bool, id *Identifier, params *Parameters, trailingComma bool, body Node) ObjectField {
-	return ObjectField{ObjectLocal, ObjectFieldVisible, false, methodSugar, nil, id, params, trailingComma, body, nil}
-}
-
 func ObjectFieldLocalNoMethod(id *Identifier, body Node) ObjectField {
-	return ObjectField{ObjectLocal, ObjectFieldVisible, false, false, nil, id, nil, false, body, nil}
+	return ObjectField{ObjectLocal, ObjectFieldVisible, false, false, nil, nil, id, nil, false, body, nil}
 }
 
 type ObjectFields []ObjectField

ast/location.go

@@ -16,14 +16,22 @@ limitations under the License.
 
 package ast
 
-import "fmt"
+import (
+	"bytes"
+	"fmt"
+)
+
+type Source struct {
+	lines []string
+}
 
 //////////////////////////////////////////////////////////////////////////////
 // Location
 
 // Location represents a single location in an (unspecified) file.
 type Location struct {
-	Line   int
+	Line int
+	// Column is a byte offset from the beginning of the line
 	Column int
 }
 
@@ -36,6 +44,13 @@ func (l *Location) String() string {
 	return fmt.Sprintf("%v:%v", l.Line, l.Column)
 }
 
+func locationBefore(a Location, b Location) bool {
+	if a.Line != b.Line {
+		return a.Line < b.Line
+	}
+	return a.Column < b.Column
+}
+
 //////////////////////////////////////////////////////////////////////////////
 // LocationRange
 
@@ -43,7 +58,15 @@ func (l *Location) String() string {
 type LocationRange struct {
 	FileName string
 	Begin    Location
-	End      Location
+	End      Location // TODO(sbarzowski) inclusive? exclusive? a gap?
+	file     *Source
+}
+
+func LocationRangeBetween(a, b *LocationRange) LocationRange {
+	if a.file != b.file {
+		panic("Cannot create a LocationRange between different files")
+	}
+	return MakeLocationRange(a.FileName, a.file, a.Begin, b.End)
 }
 
 // IsSet returns if this LocationRange has been set.
@@ -70,11 +93,101 @@ func (lr *LocationRange) String() string {
 	return fmt.Sprintf("%s(%v)-(%v)", filePrefix, lr.Begin.String(), lr.End.String())
 }
 
+func (l *LocationRange) WithCode() bool {
+	return l.Begin.Line != 0
+}
+
 // This is useful for special locations, e.g. manifestation entry point.
 func MakeLocationRangeMessage(msg string) LocationRange {
 	return LocationRange{FileName: msg}
 }
 
-func MakeLocationRange(fn string, begin Location, end Location) LocationRange {
-	return LocationRange{FileName: fn, Begin: begin, End: end}
+func MakeLocationRange(fn string, fc *Source, begin Location, end Location) LocationRange {
+	return LocationRange{FileName: fn, file: fc, Begin: begin, End: end}
+}
+
+type SourceProvider struct {
+}
+
+func (sp *SourceProvider) GetSnippet(loc LocationRange) string {
+	var result bytes.Buffer
+	if loc.Begin.Line == 0 {
+		return ""
+	}
+	for i := loc.Begin.Line; i <= loc.End.Line; i++ {
+		inLineRange := trimToLine(loc, i)
+		for j := inLineRange.Begin.Column; j < inLineRange.End.Column; j++ {
+			result.WriteByte(loc.file.lines[i-1][j-1])
+		}
+		if i != loc.End.Line {
+			result.WriteByte('\n')
+		}
+	}
+	return result.String()
+}
+
+func BuildSource(s string) *Source {
+	var result []string
+	var lineBuf bytes.Buffer
+	for _, runeValue := range s {
+		lineBuf.WriteRune(runeValue)
+		if runeValue == '\n' {
+			result = append(result, lineBuf.String())
+			lineBuf.Reset()
+		}
+	}
+	rest := lineBuf.String()
+	// Stuff after last end-of-line (EOF or some more code)
+	result = append(result, rest+"\n")
+	return &Source{result}
+}
+
+func trimToLine(loc LocationRange, line int) LocationRange {
+	if loc.Begin.Line > line {
+		panic("invalid")
+	}
+	if loc.Begin.Line != line {
+		loc.Begin.Column = 1
+	}
+	loc.Begin.Line = line
+	if loc.End.Line < line {
+		panic("invalid")
+	}
+	if loc.End.Line != line {
+		loc.End.Column = len(loc.file.lines[line-1])
+	}
+	loc.End.Line = line
+	return loc
+}
+
+// lineBeginning returns a part of the line directly before LocationRange
+// for example:
+// local x = foo()
+//           ^^^^^ <- LocationRange loc
+// then
+// local x = foo()
+// ^^^^^^^^^^ <- lineBeginning(loc)
+func LineBeginning(loc *LocationRange) LocationRange {
+	return LocationRange{
+		Begin:    Location{Line: loc.Begin.Line, Column: 1},
+		End:      loc.Begin,
+		FileName: loc.FileName,
+		file:     loc.file,
+	}
+}
+
+// lineEnding returns a part of the line directly after LocationRange
+// for example:
+// local x = foo() + test
+//           ^^^^^ <- LocationRange loc
+// then
+// local x = foo() + test
+//                ^^^^^^^ <- lineEnding(loc)
+func LineEnding(loc *LocationRange) LocationRange {
+	return LocationRange{
+		Begin:    loc.End,
+		End:      Location{Line: loc.End.Line, Column: len(loc.file.lines[loc.End.Line-1])},
+		FileName: loc.FileName,
+		file:     loc.file,
+	}
 }

builtins.go

@@ -608,7 +608,7 @@ type UnaryBuiltin struct {
 
 func getBuiltinEvaluator(e *evaluator, name ast.Identifier) *evaluator {
 	loc := ast.MakeLocationRangeMessage("<builtin>")
-	context := TraceContext{Name: "builtin function <" + string(name) + ">"}
+	context := "builtin function <" + string(name) + ">"
 	trace := TraceElement{loc: &loc, context: &context}
 	return &evaluator{i: e.i, trace: &trace}
 }

desugarer.go

@@ -128,22 +128,14 @@ func desugarFields(location ast.LocationRange, fields *ast.ObjectFields, objLeve
 		field.Expr2 = assertion
 	}
 
-	// Remove methods
 	for i := range *fields {
 		field := &((*fields)[i])
-		if !field.MethodSugar {
+		if field.Method == nil {
 			continue
 		}
-		origBody := field.Expr2
-		function := &ast.Function{
-			// TODO(sbarzowski) better location
-			NodeBase:   ast.NewNodeBaseLoc(*origBody.Loc()),
-			Parameters: *field.Params,
-			Body:       origBody,
-		}
-		field.MethodSugar = false
-		field.Params = nil
-		field.Expr2 = function
+		field.Expr2 = field.Method
+		field.Method = nil
+		// Body of the function already desugared through expr2
 	}
 
 	// Remove object-level locals
@@ -483,19 +475,11 @@ func desugar(astPtr *ast.Node, objLevel int) (err error) {
 
 	case *ast.Local:
 		for i := range node.Binds {
-			if node.Binds[i].FunctionSugar {
-				origBody := node.Binds[i].Body
-				function := &ast.Function{
-					// TODO(sbarzowski) better location
-					NodeBase:   ast.NewNodeBaseLoc(*origBody.Loc()),
-					Parameters: *node.Binds[i].Params,
-					Body:       origBody,
-				}
+			if node.Binds[i].Fun != nil {
 				node.Binds[i] = ast.LocalBind{
-					Variable:      node.Binds[i].Variable,
-					Body:          function,
-					FunctionSugar: false,
-					Params:        nil,
+					Variable: node.Binds[i].Variable,
+					Body:     node.Binds[i].Fun,
+					Fun:      nil,
 				}
 			}
 			err = desugar(&node.Binds[i].Body, objLevel)

error_formatter.go

@@ -19,6 +19,7 @@ import (
 	"bytes"
 	"fmt"
 
+	"github.com/fatih/color"
 	"github.com/google/go-jsonnet/ast"
 	"github.com/google/go-jsonnet/parser"
 )
@@ -27,10 +28,13 @@ type ErrorFormatter struct {
 	// TODO(sbarzowski) use this
 	// MaxStackTraceSize  is the maximum length of stack trace before cropping
 	MaxStackTraceSize int
-	// TODO(sbarzowski) use these
+
+	// Examples of current state of the art.
+	// http://elm-lang.org/blog/compiler-errors-for-humans
+	// https://clang.llvm.org/diagnostics.html
 	pretty   bool
 	colorful bool
-	SP       SourceProvider
+	SP       *ast.SourceProvider
 }
 
 func (ef *ErrorFormatter) format(err error) string {
@@ -46,12 +50,13 @@ func (ef *ErrorFormatter) format(err error) string {
 
 func (ef *ErrorFormatter) formatRuntime(err *RuntimeError) string {
 	return err.Error() + "\n" + ef.buildStackTrace(err.StackTrace)
-	// TODO(sbarzowski) pretty stuff
 }
 
 func (ef *ErrorFormatter) formatStatic(err *parser.StaticError) string {
-	return err.Error() + "\n"
-	// TODO(sbarzowski) pretty stuff
+	var buf bytes.Buffer
+	buf.WriteString(err.Error() + "\n")
+	ef.showCode(&buf, err.Loc)
+	return buf.String()
 }
 
 const bugURL = "https://github.com/google/go-jsonnet/issues"
@@ -61,19 +66,42 @@ func (ef *ErrorFormatter) formatInternal(err error) string {
 		"Please report a bug here: " + bugURL + "\n"
 }
 
+func (ef *ErrorFormatter) showCode(buf *bytes.Buffer, loc ast.LocationRange) {
+	errFprintf := fmt.Fprintf
+	if ef.colorful {
+		errFprintf = color.New(color.FgRed).Fprintf
+	}
+	if loc.WithCode() {
+		// TODO(sbarzowski) include line numbers
+		// TODO(sbarzowski) underline errors instead of depending only on color
+		fmt.Fprintf(buf, "\n")
+		beginning := ast.LineBeginning(&loc)
+		ending := ast.LineEnding(&loc)
+		fmt.Fprintf(buf, "%v", ef.SP.GetSnippet(beginning))
+		errFprintf(buf, "%v", ef.SP.GetSnippet(loc))
+		fmt.Fprintf(buf, "%v", ef.SP.GetSnippet(ending))
+		buf.WriteByte('\n')
+	}
+	fmt.Fprintf(buf, "\n")
+}
+
 func (ef *ErrorFormatter) buildStackTrace(frames []TraceFrame) string {
 	// https://github.com/google/jsonnet/blob/master/core/libjsonnet.cpp#L594
 	var buf bytes.Buffer
-	for _, f := range frames {
+	for i := len(frames) - 1; i >= 0; i-- {
+		f := frames[i]
+		// TODO(sbarzowski) make pretty format more readable (it's already useful)
+		if ef.pretty {
+			fmt.Fprintf(&buf, "-------------------------------------------------\n")
+		}
+		// TODO(sbarzowski) tabs are probably a bad idea
 		fmt.Fprintf(&buf, "\t%v\t%v\n", &f.Loc, f.Name)
+		if ef.pretty {
+			ef.showCode(&buf, f.Loc)
+		}
+
 		// TODO(sbarzowski) handle max stack trace size
 		// TODO(sbarzowski) I think the order of frames is reversed
 	}
 	return buf.String()
 }
-
-type SourceProvider interface {
-	// TODO(sbarzowski) problem: locationRange.FileName may not necessarily
-	// uniquely identify a file. But this is the interface we want to have here.
-	getCode(ast.LocationRange) string
-}

evaluator.go

@@ -162,11 +162,11 @@ func (e *evaluator) evaluateObject(pv potentialValue) (valueObject, error) {
 }
 
 func (e *evaluator) evalInCurrentContext(a ast.Node) (value, error) {
-	return e.i.evaluate(a, e.trace.context)
+	return e.i.evaluate(a)
 }
 
-func (e *evaluator) evalInCleanEnv(newContext *TraceContext, env *environment, ast ast.Node) (value, error) {
-	return e.i.EvalInCleanEnv(e.trace, newContext, env, ast)
+func (e *evaluator) evalInCleanEnv(env *environment, ast ast.Node) (value, error) {
+	return e.i.EvalInCleanEnv(e.trace, env, ast)
 }
 
 func (e *evaluator) lookUpVar(ident ast.Identifier) potentialValue {

imports.go

@@ -86,7 +86,7 @@ func codeToPV(e *evaluator, filename string, code string) potentialValue {
 		// The same thinking applies to external variables.
 		return makeErrorThunk(err)
 	}
-	return makeThunk("_", e.i.initialEnv, node)
+	return makeThunk(e.i.initialEnv, node)
 }
 
 func (cache *ImportCache) ImportCode(codeDir, importedPath string, e *evaluator) (value, error) {

interpreter.go

@@ -71,7 +71,7 @@ type callFrame struct {
 	// This makes callFrame a misnomer as it is technically not always a call...
 	isCall bool
 
-	// Tracing information about the place where (TODO)
+	// Tracing information about the place where it was called from.
 	trace *TraceElement
 
 	/** Reuse this stack frame for the purpose of tail call optimization. */
@@ -242,11 +242,11 @@ func (i *interpreter) getCurrentEnv(ast ast.Node) environment {
 	)
 }
 
-func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error) {
+func (i *interpreter) evaluate(a ast.Node) (value, error) {
 	e := &evaluator{
 		trace: &TraceElement{
 			loc:     a.Loc(),
-			context: context,
+			context: a.Context(),
 		},
 		i: i,
 	}
@@ -257,7 +257,7 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 		var elements []potentialValue
 		for _, el := range ast.Elements {
 			env := makeEnvironment(i.capture(el.FreeVariables()), sb)
-			elThunk := makeThunk("array_element", env, el)
+			elThunk := makeThunk(env, el)
 			elements = append(elements, elThunk)
 		}
 		return makeValueArray(elements), nil
@@ -269,8 +269,8 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 		// TODO(sbarzowski) it may make sense not to show a line in stack trace for operators
 		// 					at all in many cases. 1 + 2 + 3 + 4 + error "x" will show 5 lines
 		//					of stack trace now, and it's not that nice.
-		left := makeThunk("x", env, ast.Left)
-		right := makeThunk("y", env, ast.Right)
+		left := makeThunk(env, ast.Left)
+		right := makeThunk(env, ast.Right)
 
 		builtin := bopBuiltins[ast.Op]
 
@@ -282,7 +282,7 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 
 	case *ast.Unary:
 		env := i.getCurrentEnv(ast)
-		arg := makeThunk("x", env, ast.Expr)
+		arg := makeThunk(env, ast.Expr)
 
 		builtin := uopBuiltins[ast.Op]
 
@@ -401,7 +401,7 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 		vars := make(bindingFrame)
 		bindEnv := i.getCurrentEnv(a)
 		for _, bind := range ast.Binds {
-			th := makeThunk(bind.Variable, bindEnv, bind.Body)
+			th := makeThunk(bindEnv, bind.Body)
 
 			// recursive locals
 			vars[bind.Variable] = th
@@ -467,8 +467,7 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 			positional: make([]potentialValue, len(ast.Arguments.Positional)),
 		}
 		for i, arg := range ast.Arguments.Positional {
-			// TODO(sbarzowski) better thunk name
-			arguments.positional[i] = makeThunk("arg", argEnv, arg)
+			arguments.positional[i] = makeThunk(argEnv, arg)
 		}
 
 		return e.evaluate(function.call(arguments))
@@ -700,13 +699,12 @@ func (i *interpreter) manifestAndSerializeJSON(trace *TraceElement, v value, mul
 	return buf.String(), nil
 }
 
-func (i *interpreter) EvalInCleanEnv(fromWhere *TraceElement, newContext *TraceContext,
-	env *environment, ast ast.Node) (value, error) {
+func (i *interpreter) EvalInCleanEnv(fromWhere *TraceElement, env *environment, ast ast.Node) (value, error) {
 	err := i.newCall(fromWhere, *env)
 	if err != nil {
 		return nil, err
 	}
-	val, err := i.evaluate(ast, newContext)
+	val, err := i.evaluate(ast)
 	i.stack.pop()
 	return val, err
 }
@@ -736,12 +734,11 @@ func evaluateStd(i *interpreter) (value, error) {
 	)
 	evalLoc := ast.MakeLocationRangeMessage("During evaluation of std")
 	evalTrace := &TraceElement{loc: &evalLoc}
-	node, err := snippetToAST("std.jsonnet", getStdCode())
+	node, err := snippetToAST("<std>", getStdCode())
 	if err != nil {
 		return nil, err
 	}
-	context := TraceContext{Name: "<stdlib>"}
-	return i.EvalInCleanEnv(evalTrace, &context, &beforeStdEnv, node)
+	return i.EvalInCleanEnv(evalTrace, &beforeStdEnv, node)
 }
 
 func prepareExtVars(i *interpreter, ext vmExtMap) map[ast.Identifier]potentialValue {
@@ -796,8 +793,7 @@ func evaluate(node ast.Node, ext vmExtMap, maxStack int, importer Importer) (str
 	evalTrace := &TraceElement{
 		loc: &evalLoc,
 	}
-	context := TraceContext{Name: "<main>"}
-	result, err := i.EvalInCleanEnv(evalTrace, &context, &i.initialEnv, node)
+	result, err := i.EvalInCleanEnv(evalTrace, &i.initialEnv, node)
 	if err != nil {
 		return "", err
 	}

main_test.go

@@ -92,6 +92,7 @@ func TestMain(t *testing.T) {
 		}
 		mainTests = append(mainTests, mainTest{name: name, input: input, golden: golden})
 	}
+	errFormatter := ErrorFormatter{pretty: true}
 	for _, test := range mainTests {
 		t.Run(test.name, func(t *testing.T) {
 			vm := MakeVM()
@@ -109,7 +110,7 @@ func TestMain(t *testing.T) {
 			if err != nil {
 				// TODO(sbarzowski) perhaps somehow mark that we are processing
 				// an error. But for now we can treat them the same.
-				output = err.Error()
+				output = errFormatter.format(err)
 			}
 			output += "\n"
 			if *update {
@@ -188,19 +189,20 @@ func TestOneLineError(t *testing.T) {
 // TODO(sbarzowski) checking if the whitespace is right is quite unpleasant, what can we do about it?
 var minimalErrorTests = []errorFormattingTest{
 	{"error", `error "x"`, "RUNTIME ERROR: x\n" +
+		"	error:1:1-9	$\n" + // TODO(sbarzowski) if seems we have off-by-one in location
 		"	During evaluation	\n" +
-		"	error:1:1-9	<main>\n"}, // TODO(sbarzowski) if seems we have off-by-one in location
+		""},
 	{"error_in_func", `local x(n) = if n == 0 then error "x" else x(n - 1); x(3)`, "RUNTIME ERROR: x\n" +
+		"	error_in_func:1:29-37	function <x>\n" +
+		"	error_in_func:1:44-52	function <x>\n" +
+		"	error_in_func:1:44-52	function <x>\n" +
+		"	error_in_func:1:44-52	function <x>\n" +
+		"	error_in_func:1:54-58	$\n" +
 		"	During evaluation	\n" +
-		"	error_in_func:1:54-58	<main>\n" +
-		"	error_in_func:1:44-52	function <anonymous>\n" +
-		"	error_in_func:1:44-52	function <anonymous>\n" +
-		"	error_in_func:1:44-52	function <anonymous>\n" +
-		"	error_in_func:1:29-37	function <anonymous>\n" +
 		""},
 	{"error_in_error", `error (error "x")`, "RUNTIME ERROR: x\n" +
+		"	error_in_error:1:8-16	$\n" +
 		"	During evaluation	\n" +
-		"	error_in_error:1:8-16	<main>\n" +
 		""},
 }
 
@@ -210,3 +212,6 @@ func TestMinimalError(t *testing.T) {
 		return formatter.format(r)
 	})
 }
+
+// TODO(sbarzowski) test pretty errors once they are stable-ish
+// probably "golden" pattern is the right one for that

parser/context.go

@@ -0,0 +1,371 @@
+/*
+Copyright 2017 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package parser
+
+import (
+	"fmt"
+
+	"github.com/google/go-jsonnet/ast"
+)
+
+var topLevelContext = "$"
+
+const anonymous = "anonymous"
+
+// TODO(sbarzowski) polish children functions and consider moving to AST
+// and exporting
+
+// directChildren are children of AST node that are executed in the same context
+// and environment as their parent
+//
+// They must satisfy the following rules:
+// * (no-delayed-evaluation) They are evaluated when their parent is evaluated or never.
+// * (no-indirect-evaluation) They cannot be evaluated during evaluation of any non-direct children
+// * (same-environment) They must be evaluated in the same environment as their parent
+func directChildren(node ast.Node) []ast.Node {
+	switch node := node.(type) {
+	case *ast.Apply:
+		return []ast.Node{node.Target}
+		// TODO(sbarzowski) tailstrict call arguments (once we have tailstrict)
+	case *ast.ApplyBrace:
+		return []ast.Node{node.Left, node.Right}
+	case *ast.Array:
+		return nil
+	case *ast.Assert:
+		return []ast.Node{node.Cond, node.Message, node.Rest}
+	case *ast.Binary:
+		return []ast.Node{node.Left, node.Right}
+	case *ast.Conditional:
+		return []ast.Node{node.Cond, node.BranchTrue, node.BranchFalse}
+	case *ast.Dollar:
+		return nil
+	case *ast.Error:
+		return []ast.Node{node.Expr}
+	case *ast.Function:
+		return nil
+	case *ast.Import:
+		return nil
+	case *ast.ImportStr:
+		return nil
+	case *ast.Index:
+		return []ast.Node{node.Target, node.Index}
+	case *ast.Slice:
+		return []ast.Node{node.Target, node.BeginIndex, node.EndIndex, node.Step}
+	case *ast.Local:
+		return []ast.Node{node.Body}
+	case *ast.LiteralBoolean:
+		return nil
+	case *ast.LiteralNull:
+		return nil
+	case *ast.LiteralNumber:
+		return nil
+	case *ast.LiteralString:
+		return nil
+	case *ast.Object:
+		return objectFieldsDirectChildren(node.Fields)
+	case *ast.ArrayComp:
+		result := []ast.Node{}
+		spec := &node.Spec
+		for spec != nil {
+			result = append(result, spec.Expr)
+			for _, ifspec := range spec.Conditions {
+				result = append(result, ifspec.Expr)
+			}
+			spec = spec.Outer
+		}
+		return result
+	case *ast.ObjectComp:
+		result := objectFieldsDirectChildren(node.Fields)
+		spec := &node.Spec
+		for spec != nil {
+			result = append(result, spec.Expr)
+			for _, ifspec := range spec.Conditions {
+				result = append(result, ifspec.Expr)
+			}
+			spec = spec.Outer
+		}
+		return result
+	case *ast.Self:
+		return nil
+	case *ast.SuperIndex:
+		return []ast.Node{node.Index}
+	case *ast.InSuper:
+		return []ast.Node{node.Index}
+	case *ast.Unary:
+		return []ast.Node{node.Expr}
+	case *ast.Var:
+		return nil
+	}
+	panic(fmt.Sprintf("directChildren: Unknown node %#v", node))
+}
+
+// thunkChildren are children of AST node that are executed in a new context
+// and capture environment from parent (thunked)
+// TODO(sbarzowski) Make sure it works well with boundary cases like tailstrict arguments,
+//					make it more precise.
+// Rules:
+// * (same-environment) They must be evaluated in the same environment as their parent
+// * (not-direct) If they can be direct children, they should (and cannot be thunked).
+func thunkChildren(node ast.Node) []ast.Node {
+	switch node := node.(type) {
+	case *ast.Apply:
+		var nodes []ast.Node
+		for _, arg := range node.Arguments.Positional {
+			nodes = append(nodes, arg)
+		}
+		for _, arg := range node.Arguments.Named {
+			nodes = append(nodes, arg.Arg)
+		}
+		return nodes
+	case *ast.ApplyBrace:
+		return nil
+	case *ast.Array:
+		return node.Elements
+	case *ast.Assert:
+		return nil
+	case *ast.Binary:
+		return nil
+	case *ast.Conditional:
+		return nil
+	case *ast.Dollar:
+		return nil
+	case *ast.Error:
+		return nil
+	case *ast.Function:
+		return nil
+	case *ast.Import:
+		return nil
+	case *ast.ImportStr:
+		return nil
+	case *ast.Index:
+		return nil
+	case *ast.Slice:
+		return nil
+	case *ast.Local:
+		// TODO(sbarzowski) complicated
+		return nil
+	case *ast.LiteralBoolean:
+		return nil
+	case *ast.LiteralNull:
+		return nil
+	case *ast.LiteralNumber:
+		return nil
+	case *ast.LiteralString:
+		return nil
+	case *ast.Object:
+		return nil
+	case *ast.ArrayComp:
+		return []ast.Node{node.Body}
+	case *ast.ObjectComp:
+		return nil
+	case *ast.Self:
+		return nil
+	case *ast.SuperIndex:
+		return nil
+	case *ast.InSuper:
+		return nil
+	case *ast.Unary:
+		return nil
+	case *ast.Var:
+		return nil
+	}
+	panic(fmt.Sprintf("thunkChildren: Unknown node %#v", node))
+}
+
+func objectFieldsDirectChildren(fields ast.ObjectFields) ast.Nodes {
+	result := ast.Nodes{}
+	for _, field := range fields {
+		if field.Expr1 != nil {
+			result = append(result, field.Expr1)
+		}
+	}
+	return result
+}
+
+func inObjectFieldsChildren(fields ast.ObjectFields) ast.Nodes {
+	result := ast.Nodes{}
+	for _, field := range fields {
+		if field.MethodSugar {
+			result = append(result, field.Method)
+		} else {
+			if field.Expr2 != nil {
+				result = append(result, field.Expr2)
+			}
+			if field.Expr3 != nil {
+				result = append(result, field.Expr3)
+			}
+		}
+	}
+	return result
+}
+
+// children that are neither direct nor thunked, e.g. object field body
+// They are evaluated in a different environment from their parent.
+func specialChildren(node ast.Node) []ast.Node {
+	switch node := node.(type) {
+	case *ast.Apply:
+		return nil
+	case *ast.ApplyBrace:
+		return nil
+	case *ast.Array:
+		return nil
+	case *ast.Assert:
+		return nil
+	case *ast.Binary:
+		return nil
+	case *ast.Conditional:
+		return nil
+	case *ast.Dollar:
+		return nil
+	case *ast.Error:
+		return nil
+	case *ast.Function:
+		// TODO(sbarzowski) this
+		return nil
+	case *ast.Import:
+		return nil
+	case *ast.ImportStr:
+		return nil
+	case *ast.Index:
+		return nil
+	case *ast.Slice:
+		return nil
+	case *ast.Local:
+		return nil
+	case *ast.LiteralBoolean:
+		return nil
+	case *ast.LiteralNull:
+		return nil
+	case *ast.LiteralNumber:
+		return nil
+	case *ast.LiteralString:
+		return nil
+	case *ast.Object:
+		return inObjectFieldsChildren(node.Fields)
+	case *ast.ArrayComp:
+		return []ast.Node{node.Body}
+	case *ast.ObjectComp:
+
+	case *ast.Self:
+		return nil
+	case *ast.SuperIndex:
+		return nil
+	case *ast.InSuper:
+		return nil
+	case *ast.Unary:
+		return nil
+	case *ast.Var:
+		return nil
+	}
+	panic(fmt.Sprintf("specialChildren: Unknown node %#v", node))
+}
+
+func children(node ast.Node) []ast.Node {
+	var result []ast.Node
+	result = append(result, directChildren(node)...)
+	result = append(result, thunkChildren(node)...)
+	result = append(result, specialChildren(node)...)
+	return result
+}
+
+func functionContext(funcName string) *string {
+	r := "function <" + funcName + ">"
+	return &r
+}
+
+func objectContext(objName string) *string {
+	r := "object <" + objName + ">"
+	return &r
+}
+
+// addContext adds context to a node and its whole subtree.
+//
+// context is the surrounding context of a node (e.g. a function it's in)
+//
+// bind is a name that the node is bound to, i.e. if node is a local bind body
+// then bind is its name. For nodes that are not bound to variables `anonymous`
+// should be passed. For example:
+// local x = 2 + 2; x
+// In such case bind for binary node 2 + 2 is "x" and for every other node,
+// including its children, its anonymous.
+func addContext(node ast.Node, context *string, bind string) {
+	if node == nil {
+		return
+	}
+
+	node.SetContext(context)
+
+	switch node := node.(type) {
+	case *ast.Function:
+		funContext := functionContext(bind)
+		addContext(node.Body, funContext, anonymous)
+		for i := range node.Parameters.Named {
+			// Default arguments have the same context as the function body.
+			addContext(node.Parameters.Named[i].DefaultArg, funContext, anonymous)
+		}
+	case *ast.Object:
+		// TODO(sbarzowski) include fieldname, maybe even chains
+
+		outOfObject := directChildren(node)
+		for _, f := range outOfObject {
+			// This actually is evaluated outside of object
+			addContext(f, context, anonymous)
+		}
+
+		objContext := objectContext(bind)
+		inObject := inObjectFieldsChildren(node.Fields)
+		for _, f := range inObject {
+			// This actually is evaluated outside of object
+			addContext(f, objContext, anonymous)
+		}
+
+	case *ast.ObjectComp:
+		outOfObject := directChildren(node)
+		for _, f := range outOfObject {
+			// This actually is evaluated outside of object
+			addContext(f, context, anonymous)
+		}
+
+		objContext := objectContext(bind)
+		inObject := inObjectFieldsChildren(node.Fields)
+		for _, f := range inObject {
+			// This actually is evaluated outside of object
+			addContext(f, objContext, anonymous)
+		}
+
+	case *ast.Local:
+		for _, bind := range node.Binds {
+			namedThunkContext := "thunk <" + string(bind.Variable) + "> from <" + *context + ">"
+			if bind.Fun != nil {
+				addContext(bind.Fun, &namedThunkContext, string(bind.Variable))
+			} else {
+				addContext(bind.Body, &namedThunkContext, string(bind.Variable))
+			}
+		}
+		addContext(node.Body, context, bind)
+	default:
+		for _, child := range directChildren(node) {
+			addContext(child, context, anonymous)
+		}
+
+		// TODO(sbarzowski) avoid "thunk from <thunk from..."
+		thunkContext := "thunk from <" + *context + ">"
+		for _, child := range thunkChildren(node) {
+			addContext(child, &thunkContext, anonymous)
+		}
+	}
+}

parser/lexer.go

@@ -245,6 +245,7 @@ type position struct {
 type lexer struct {
 	fileName string // The file name being lexed, only used for errors
 	input    string // The input string
+	source   *ast.Source
 
 	pos  position // Current position in input
 	prev position // Previous position in input
@@ -263,6 +264,7 @@ func makeLexer(fn string, input string) *lexer {
 	return &lexer{
 		fileName:      fn,
 		input:         input,
+		source:        ast.BuildSource(input),
 		pos:           position{byteNo: 0, lineNo: 1, lineStart: 0},
 		prev:          position{byteNo: lexEOF, lineNo: 0, lineStart: 0},
 		tokenStartLoc: ast.Location{Line: 1, Column: 1},
@@ -337,7 +339,7 @@ func (l *lexer) emitFullToken(kind tokenKind, data, stringBlockIndent, stringBlo
 		data:                  data,
 		stringBlockIndent:     stringBlockIndent,
 		stringBlockTermIndent: stringBlockTermIndent,
-		loc: ast.MakeLocationRange(l.fileName, l.tokenStartLoc, l.location()),
+		loc: ast.MakeLocationRange(l.fileName, l.source, l.tokenStartLoc, l.location()),
 	})
 	l.fodder = fodder{}
 }
@@ -367,6 +369,10 @@ func (l *lexer) addFodder(kind fodderKind, data string) {
 	l.fodder = append(l.fodder, fodderElement{kind: kind, data: data})
 }
 
+func (l *lexer) makeStaticErrorPoint(msg string, loc ast.Location) StaticError {
+	return StaticError{Msg: msg, Loc: ast.MakeLocationRange(l.fileName, l.source, loc, loc)}
+}
+
 // lexNumber will consume a number and emit a token.  It is assumed
 // that the next rune to be served by the lexer will be a leading digit.
 func (l *lexer) lexNumber() error {
@@ -431,9 +437,9 @@ outerLoop:
 			case r >= '0' && r <= '9':
 				state = numAfterDigit
 			default:
-				return MakeStaticErrorPoint(
+				return l.makeStaticErrorPoint(
 					fmt.Sprintf("Couldn't lex number, junk after decimal point: %v", strconv.QuoteRuneToASCII(r)),
-					l.fileName, l.prevLocation())
+					l.prevLocation())
 			}
 		case numAfterDigit:
 			switch {
@@ -451,17 +457,17 @@ outerLoop:
 			case r >= '0' && r <= '9':
 				state = numAfterExpDigit
 			default:
-				return MakeStaticErrorPoint(
+				return l.makeStaticErrorPoint(
 					fmt.Sprintf("Couldn't lex number, junk after 'E': %v", strconv.QuoteRuneToASCII(r)),
-					l.fileName, l.prevLocation())
+					l.prevLocation())
 			}
 		case numAfterExpSign:
 			if r >= '0' && r <= '9' {
 				state = numAfterExpDigit
 			} else {
-				return MakeStaticErrorPoint(
+				return l.makeStaticErrorPoint(
 					fmt.Sprintf("Couldn't lex number, junk after exponent sign: %v", strconv.QuoteRuneToASCII(r)),
-					l.fileName, l.prevLocation())
+					l.prevLocation())
 			}
 
 		case numAfterExpDigit:
@@ -558,8 +564,8 @@ func (l *lexer) lexSymbol() error {
 		l.resetTokenStart() // Throw out the leading /*
 		for r = l.next(); ; r = l.next() {
 			if r == lexEOF {
-				return MakeStaticErrorPoint("Multi-line comment has no terminating */",
-					l.fileName, commentStartLoc)
+				return l.makeStaticErrorPoint("Multi-line comment has no terminating */",
+					commentStartLoc)
 			}
 			if r == '*' && l.peek() == '/' {
 				commentData := l.input[l.tokenStart : l.pos.byteNo-1] // Don't include trailing */
@@ -584,8 +590,8 @@ func (l *lexer) lexSymbol() error {
 		numWhiteSpace := checkWhitespace(l.input[l.pos.byteNo:], l.input[l.pos.byteNo:])
 		stringBlockIndent := l.input[l.pos.byteNo : l.pos.byteNo+numWhiteSpace]
 		if numWhiteSpace == 0 {
-			return MakeStaticErrorPoint("Text block's first line must start with whitespace",
-				l.fileName, commentStartLoc)
+			return l.makeStaticErrorPoint("Text block's first line must start with whitespace",
+				commentStartLoc)
 		}
 
 		for {
@@ -595,8 +601,7 @@ func (l *lexer) lexSymbol() error {
 			l.acceptN(numWhiteSpace)
 			for r = l.next(); r != '\n'; r = l.next() {
 				if r == lexEOF {
-					return MakeStaticErrorPoint("Unexpected EOF",
-						l.fileName, commentStartLoc)
+					return l.makeStaticErrorPoint("Unexpected EOF", commentStartLoc)
 				}
 				cb.WriteRune(r)
 			}
@@ -618,8 +623,7 @@ func (l *lexer) lexSymbol() error {
 				}
 				l.backup()
 				if !strings.HasPrefix(l.input[l.pos.byteNo:], "|||") {
-					return MakeStaticErrorPoint("Text block not terminated with |||",
-						l.fileName, commentStartLoc)
+					return l.makeStaticErrorPoint("Text block not terminated with |||", commentStartLoc)
 				}
 				l.acceptN(3) // Skip '|||'
 				l.emitFullToken(tokenStringBlock, cb.String(),
@@ -710,7 +714,7 @@ func Lex(fn string, input string) (tokens, error) {
 			l.resetTokenStart() // Don't include the quotes in the token data
 			for r = l.next(); ; r = l.next() {
 				if r == lexEOF {
-					return nil, MakeStaticErrorPoint("Unterminated String", l.fileName, stringStartLoc)
+					return nil, l.makeStaticErrorPoint("Unterminated String", stringStartLoc)
 				}
 				if r == '"' {
 					l.backup()
@@ -728,7 +732,7 @@ func Lex(fn string, input string) (tokens, error) {
 			l.resetTokenStart() // Don't include the quotes in the token data
 			for r = l.next(); ; r = l.next() {
 				if r == lexEOF {
-					return nil, MakeStaticErrorPoint("Unterminated String", l.fileName, stringStartLoc)
+					return nil, l.makeStaticErrorPoint("Unterminated String", stringStartLoc)
 				}
 				if r == '\'' {
 					l.backup()
@@ -757,15 +761,14 @@ func Lex(fn string, input string) (tokens, error) {
 			} else if quot == '\'' {
 				kind = tokenVerbatimStringSingle
 			} else {
-				return nil, MakeStaticErrorPoint(
+				return nil, l.makeStaticErrorPoint(
 					fmt.Sprintf("Couldn't lex verbatim string, junk after '@': %v", quot),
-					l.fileName,
 					stringStartLoc,
 				)
 			}
 			for r = l.next(); ; r = l.next() {
 				if r == lexEOF {
-					return nil, MakeStaticErrorPoint("Unterminated String", l.fileName, stringStartLoc)
+					return nil, l.makeStaticErrorPoint("Unterminated String", stringStartLoc)
 				} else if r == quot {
 					if l.peek() == quot {
 						l.next()
@@ -799,9 +802,9 @@ func Lex(fn string, input string) (tokens, error) {
 					return nil, err
 				}
 			} else {
-				return nil, MakeStaticErrorPoint(
+				return nil, l.makeStaticErrorPoint(
 					fmt.Sprintf("Could not lex the character %s", strconv.QuoteRuneToASCII(r)),
-					l.fileName, l.prevLocation())
+					l.prevLocation())
 			}
 
 		}

parser/parser.go

@@ -61,11 +61,11 @@ func makeUnexpectedError(t *token, while string) error {
 }
 
 func locFromTokens(begin, end *token) ast.LocationRange {
-	return ast.MakeLocationRange(begin.loc.FileName, begin.loc.Begin, end.loc.End)
+	return ast.LocationRangeBetween(&begin.loc, &end.loc)
 }
 
 func locFromTokenAST(begin *token, end ast.Node) ast.LocationRange {
-	return ast.MakeLocationRange(begin.loc.FileName, begin.loc.Begin, end.Loc().End)
+	return ast.LocationRangeBetween(&begin.loc, end.Loc())
 }
 
 // ---------------------------------------------------------------------------
@@ -219,36 +219,36 @@ func (p *parser) parseBind(binds *ast.LocalBinds) error {
 		}
 	}
 
+	var fun *ast.Function
 	if p.peek().kind == tokenParenL {
 		p.pop()
 		params, gotComma, err := p.parseParameters("function parameter")
 		if err != nil {
 			return err
 		}
-		_, err = p.popExpectOp("=")
-		if err != nil {
-			return err
-		}
-		body, err := p.parse(maxPrecedence)
-		if err != nil {
-			return err
-		}
-		*binds = append(*binds, ast.LocalBind{
-			Variable:      ast.Identifier(varID.data),
-			Body:          body,
-			FunctionSugar: true,
-			Params:        params,
+		fun = &ast.Function{
+			Parameters:    *params,
 			TrailingComma: gotComma,
+		}
+	}
+
+	_, err = p.popExpectOp("=")
+	if err != nil {
+		return err
+	}
+	body, err := p.parse(maxPrecedence)
+	if err != nil {
+		return err
+	}
+
+	if fun != nil {
+		fun.Body = body
+		*binds = append(*binds, ast.LocalBind{
+			Variable: ast.Identifier(varID.data),
+			Body:     body,
+			Fun:      fun,
 		})
 	} else {
-		_, err = p.popExpectOp("=")
-		if err != nil {
-			return err
-		}
-		body, err := p.parse(maxPrecedence)
-		if err != nil {
-			return err
-		}
 		*binds = append(*binds, ast.LocalBind{
 			Variable: ast.Identifier(varID.data),
 			Body:     body,
@@ -299,6 +299,7 @@ func (p *parser) parseObjectAssignmentOp() (plusSugar bool, hide ast.ObjectField
 // +gen set
 type LiteralField string
 
+// Parse object or object comprehension without leading brace
 func (p *parser) parseObjectRemainder(tok *token) (ast.Node, *token, error) {
 	var fields ast.ObjectFields
 	literalFields := make(literalFieldSet)
@@ -451,11 +452,21 @@ func (p *parser) parseObjectRemainder(tok *token) (ast.Node, *token, error) {
 				return nil, nil, err
 			}
 
+			var method *ast.Function
+			if isMethod {
+				method = &ast.Function{
+					Parameters:    *params,
+					TrailingComma: methComma,
+					Body:          body,
+				}
+			}
+
 			fields = append(fields, ast.ObjectField{
 				Kind:          kind,
 				Hide:          hide,
 				SuperSugar:    plusSugar,
 				MethodSugar:   isMethod,
+				Method:        method,
 				Expr1:         expr1,
 				Id:            id,
 				Params:        params,
@@ -475,6 +486,8 @@ func (p *parser) parseObjectRemainder(tok *token) (ast.Node, *token, error) {
 				return nil, nil, MakeStaticError(fmt.Sprintf("Duplicate local var: %v", id), varID.loc)
 			}
 
+			// TODO(sbarzowski) Can we reuse regular local bind parsing here?
+
 			isMethod := false
 			funcComma := false
 			var params *ast.Parameters
@@ -496,6 +509,15 @@ func (p *parser) parseObjectRemainder(tok *token) (ast.Node, *token, error) {
 				return nil, nil, err
 			}
 
+			var method *ast.Function
+			if isMethod {
+				method = &ast.Function{
+					Parameters:    *params,
+					TrailingComma: funcComma,
+					Body:          body,
+				}
+			}
+
 			binds.Add(id)
 
 			fields = append(fields, ast.ObjectField{
@@ -503,6 +525,7 @@ func (p *parser) parseObjectRemainder(tok *token) (ast.Node, *token, error) {
 				Hide:          ast.ObjectFieldVisible,
 				SuperSugar:    false,
 				MethodSugar:   isMethod,
+				Method:        method,
 				Id:            &id,
 				Params:        params,
 				TrailingComma: funcComma,
@@ -1165,5 +1188,7 @@ func Parse(t tokens) (ast.Node, error) {
 		return nil, MakeStaticError(fmt.Sprintf("Did not expect: %v", p.peek()), p.peek().loc)
 	}
 
+	addContext(expr, &topLevelContext, anonymous)
+
 	return expr, nil
 }

parser/parser_test.go

@@ -16,6 +16,7 @@ limitations under the License.
 package parser
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -124,15 +125,19 @@ var tests = []string{
 
 func TestParser(t *testing.T) {
 	for _, s := range tests {
-		tokens, err := Lex("test", s)
-		if err != nil {
-			t.Errorf("Unexpected lex error\n  input: %v\n  error: %v", s, err)
-			continue
-		}
-		_, err = Parse(tokens)
-		if err != nil {
-			t.Errorf("Unexpected parse error\n  input: %v\n  error: %v", s, err)
-		}
+		t.Run(s, func(t *testing.T) {
+			fmt.Println(s)
+			tokens, err := Lex("test", s)
+			if err != nil {
+				t.Errorf("Unexpected lex error\n  input: %v\n  error: %v", s, err)
+				return
+			}
+			_, err = Parse(tokens)
+			if err != nil {
+				t.Errorf("Unexpected parse error\n  input: %v\n  error: %v", s, err)
+			}
+		})
+
 	}
 }
 
@@ -246,19 +251,21 @@ var errorTests = []testError{
 
 func TestParserErrors(t *testing.T) {
 	for _, s := range errorTests {
-		tokens, err := Lex("test", s.input)
-		if err != nil {
-			t.Errorf("Unexpected lex error\n  input: %v\n  error: %v", s.input, err)
-			continue
-		}
-		_, err = Parse(tokens)
-		if err == nil {
-			t.Errorf("Expected parse error but got success\n  input: %v", s.input)
-			continue
-		}
-		if err.Error() != s.err {
-			t.Errorf("Error string not as expected\n  input: %v\n  expected error: %v\n  actual error: %v", s.input, s.err, err.Error())
-		}
+		t.Run(s.input, func(t *testing.T) {
+			tokens, err := Lex("test", s.input)
+			if err != nil {
+				t.Errorf("Unexpected lex error\n  input: %v\n  error: %v", s.input, err)
+				return
+			}
+			_, err = Parse(tokens)
+			if err == nil {
+				t.Errorf("Expected parse error but got success\n  input: %v", s.input)
+				return
+			}
+			if err.Error() != s.err {
+				t.Errorf("Error string not as expected\n  input: %v\n  expected error: %v\n  actual error: %v", s.input, s.err, err.Error())
+			}
+		})
 	}
 
 }

parser/static_error.go

@@ -36,10 +36,6 @@ func MakeStaticErrorMsg(msg string) StaticError {
 	return StaticError{Msg: msg}
 }
 
-func MakeStaticErrorPoint(msg string, fn string, l ast.Location) StaticError {
-	return StaticError{Msg: msg, Loc: ast.MakeLocationRange(fn, l, l)}
-}
-
 func MakeStaticError(msg string, lr ast.LocationRange) StaticError {
 	return StaticError{Msg: msg, Loc: lr}
 }

runtime_error.go

@@ -48,20 +48,15 @@ func traceElementToTraceFrame(trace *TraceElement) TraceFrame {
 	tf := TraceFrame{Loc: *trace.loc}
 	if trace.context != nil {
 		// TODO(sbarzowski) maybe it should never be nil
-		tf.Name = trace.context.Name
+		tf.Name = *trace.context
 	} else {
 		tf.Name = ""
 	}
 	return tf
 }
 
-type TraceContext struct {
-	// Human readable name - e.g. function <foo>
-	Name string
-}
-
 // TODO(sbarzowski) better name
 type TraceElement struct {
 	loc     *ast.LocationRange
-	context *TraceContext
+	context ast.Context
 }

testdata/".golden

@@ -1 +1,5 @@
 testdata/":2:1 Unexpected end of file.
+
+
+
+

testdata/'.golden

@@ -1 +1,5 @@
 testdata/':2:1 Unexpected end of file.
+
+
+
+

testdata/arrcomp5.golden

@@ -1 +1,5 @@
 testdata/arrcomp5:1:14-15 Unknown variable: x
+
+[y for y in [x + 1] for x in [1, 2, 3]]
+
+

testdata/arrcomp_if4.golden

@@ -1 +1,5 @@
 testdata/arrcomp_if4:1:33-34 Unknown variable: y
+
+[[x, y] for x in [1,2,3,4,5] if y == 3 for y in [1,2,3,4,5]]
+
+

testdata/arrcomp_if6.golden

@@ -1 +1,13 @@
 RUNTIME ERROR: x
+-------------------------------------------------
+	testdata/arrcomp_if6:1:20-28	$
+
+[x for x in [1] if error "x"]
+
+-------------------------------------------------
+	<builtin>	builtin function <flatMap>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/arrcomp_if7.golden

@@ -1 +1,11 @@
 RUNTIME ERROR: Unexpected type number, expected boolean
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	<builtin>	builtin function <flatMap>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert3.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Assertion failed
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert_equal4.golden

@@ -1 +1,15 @@
 RUNTIME ERROR: Assertion failed. {"x": 1} != {"x": 2}
+-------------------------------------------------
+	<std>:649:13-56	function <anonymous>
+
+            error "Assertion failed. " + a + " != " + b,
+
+-------------------------------------------------
+	testdata/assert_equal4:1:1-32	$
+
+std.assertEqual({x: 1}, {x: 2})
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert_equal5.golden

@@ -0,0 +1,17 @@
+RUNTIME ERROR: Assertion failed. 
+  != 
+
+-------------------------------------------------
+	<std>:649:13-56	function <anonymous>
+
+            error "Assertion failed. " + a + " != " + b,
+
+-------------------------------------------------
+	testdata/assert_equal5:1:1-29	$
+
+std.assertEqual("\n ", "\n")
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert_equal5.jsonnet

@@ -0,0 +1 @@
+std.assertEqual("\n ", "\n")

testdata/assert_equal6.golden

@@ -0,0 +1,15 @@
+RUNTIME ERROR: Assertion failed.  != 
+-------------------------------------------------
+	<std>:649:13-56	function <anonymous>
+
+            error "Assertion failed. " + a + " != " + b,
+
+-------------------------------------------------
+	testdata/assert_equal6:1:1-34	$
+
+std.assertEqual("\u001b[31m", "")
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert_equal6.jsonnet

@@ -0,0 +1 @@
+std.assertEqual("\u001b[31m", "")

testdata/assert_failed.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Assertion failed
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/assert_failed_custom.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Custom Message
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/bad_function_call.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: function expected 1 argument(s), but got 0
+-------------------------------------------------
+	testdata/bad_function_call:1:1-18	$
+
+(function(x) x)()
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/bad_function_call2.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: function expected 1 argument(s), but got 2
+-------------------------------------------------
+	testdata/bad_function_call2:1:1-22	$
+
+(function(x) x)(1, 2)
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/bad_function_call_and_error.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: function expected 1 argument(s), but got 2
+-------------------------------------------------
+	testdata/bad_function_call_and_error:1:1-38	$
+
+(function(x) x)(error "x", error "y")
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/bitwise_and4.golden

@@ -1 +1,15 @@
 RUNTIME ERROR: x
+-------------------------------------------------
+	testdata/bitwise_and4:1:5-13	$
+
+1 & error "x"
+
+-------------------------------------------------
+	testdata/bitwise_and4:1:1-13	$
+
+1 & error "x"
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/bitwise_xor7.golden

@@ -1 +1,15 @@
 RUNTIME ERROR: x
+-------------------------------------------------
+	testdata/bitwise_xor7:1:5-13	$
+
+1 ^ error "x"
+
+-------------------------------------------------
+	testdata/bitwise_xor7:1:1-13	$
+
+1 ^ error "x"
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/block_string.golden

@@ -0,0 +1 @@
+"x\n\ty\nz\n"

testdata/block_string.jsonnet

@@ -0,0 +1,5 @@
+|||
+	x
+		y
+	z
+|||

testdata/builtinChar3.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Codepoints must be >= 0, got -1
+-------------------------------------------------
+	<builtin>	builtin function <char>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtinChar5.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Invalid unicode codepoint, got 1.114112e+06
+-------------------------------------------------
+	<builtin>	builtin function <char>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtinObjectHasExBadField.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Unexpected type number, expected string
+-------------------------------------------------
+	<builtin>	builtin function <objectHasEx>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtinObjectHasExBadObject.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Unexpected type number, expected object
+-------------------------------------------------
+	<builtin>	builtin function <objectHasEx>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtin_exp3.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Overflow
+-------------------------------------------------
+	<builtin>	builtin function <exp>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtin_exp5.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Overflow
+-------------------------------------------------
+	<builtin>	builtin function <exp>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtin_log5.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Overflow
+-------------------------------------------------
+	<builtin>	builtin function <log>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtin_log7.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Not a number
+-------------------------------------------------
+	<builtin>	builtin function <log>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/builtin_log8.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Not a number
+-------------------------------------------------
+	<builtin>	builtin function <log>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/call_number.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Unexpected type number, expected function
+-------------------------------------------------
+	testdata/call_number:1:1-5	$
+
+42()
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/div4.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Overflow
+-------------------------------------------------
+	testdata/div4:1:1-19	$
+
+1/(1e-160)/(1e-160)
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/div_by_zero.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Division by zero.
+-------------------------------------------------
+	testdata/div_by_zero:1:1-4	$
+
+1/0
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/double_thunk.golden

@@ -0,0 +1,20 @@
+RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/double_thunk:1:21-31	thunk <y> from <thunk <x> from <$>>
+
+local x = local y = error "xxx"; y; x
+
+-------------------------------------------------
+	testdata/double_thunk:1:34-35	thunk <x> from <$>
+
+local x = local y = error "xxx"; y; x
+
+-------------------------------------------------
+	testdata/double_thunk:1:37-38	$
+
+local x = local y = error "xxx"; y; x
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/double_thunk.jsonnet

@@ -0,0 +1 @@
+local x = local y = error "xxx"; y; x

testdata/error.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: 42
+-------------------------------------------------
+	testdata/error:1:1-10	$
+
+error "42"
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/error_from_array.golden

@@ -0,0 +1,15 @@
+RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/error_from_array:1:2-12	thunk from <$>
+
+[error "xxx"][0]
+
+-------------------------------------------------
+	testdata/error_from_array:1:1-17	$
+
+[error "xxx"][0]
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/error_from_array.jsonnet

@@ -0,0 +1 @@
+[error "xxx"][0]

testdata/error_from_func.golden

@@ -0,0 +1,15 @@
+RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/error_from_func:1:25-32	function <foo>
+
+local foo = function(x) error x; foo("xxx")
+
+-------------------------------------------------
+	testdata/error_from_func:1:34-44	$
+
+local foo = function(x) error x; foo("xxx")
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/error_from_func.jsonnet

@@ -0,0 +1 @@
+local foo = function(x) error x; foo("xxx")

testdata/error_hexnumber.golden

@@ -1 +1,5 @@
 testdata/error_hexnumber:1:2-5 Did not expect: (IDENTIFIER, "x42")
+
+0x42
+
+

testdata/error_in_method.golden

@@ -0,0 +1,15 @@
+RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/error_in_method:1:23-30	function <anonymous>
+
+local obj = { foo(x): error x }; obj.foo("xxx")
+
+-------------------------------------------------
+	testdata/error_in_method:1:34-48	$
+
+local obj = { foo(x): error x }; obj.foo("xxx")
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/error_in_method.jsonnet

@@ -0,0 +1,4 @@
+local obj = { foo(x): error x }; obj.foo("xxx")
+
+
+

testdata/error_in_object_local.golden

@@ -0,0 +1,15 @@
+RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/error_in_object_local:1:20-29	function <anonymous>
+
+{ local foo(bar) = error bar, baz: foo("xxx") }
+
+-------------------------------------------------
+	testdata/error_in_object_local:1:36-46	object <anonymous>
+
+{ local foo(bar) = error bar, baz: foo("xxx") }
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/error_in_object_local.jsonnet

@@ -0,0 +1 @@
+{ local foo(bar) = error bar, baz: foo("xxx") }

testdata/extvar_error.golden

@@ -1 +1,13 @@
 RUNTIME ERROR: xxx
+-------------------------------------------------
+	<extvar:errorVar>:1:1-11	$
+
+error 'xxx'
+
+-------------------------------------------------
+	<builtin>	builtin function <extVar>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/extvar_hermetic.golden

@@ -1 +1,5 @@
 <extvar:UndeclaredX>:1:1-2 Unknown variable: x
+
+x
+
+

testdata/extvar_static_error.golden

@@ -1 +1,5 @@
 <extvar:staticErrorVar>:1:1-2 Unexpected: (")", ")") while parsing terminal
+
+)
+
+

testdata/extvar_unknown.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Undefined external variable: UNKNOWN
+-------------------------------------------------
+	<builtin>	builtin function <extVar>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/fieldname_not_string.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Field name must be string, got number
+-------------------------------------------------
+	testdata/fieldname_not_string:1:1-15	$
+
+{ [1234]: 42 }
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/function.golden

@@ -1 +1,5 @@
 RUNTIME ERROR: Couldn't manifest function in JSON output.
+-------------------------------------------------
+	During manifestation	
+
+

testdata/import_block_literal.golden

@@ -1 +1,7 @@
 testdata/import_block_literal:(1:8)-(3:4) Block string literals not allowed in imports
+
+import |||
+	block_literals_for_imports_are_not_allowed_and_make_exactly_zero_sense
+|||
+
+

testdata/import_computed.golden

@@ -1 +1,5 @@
 testdata/import_computed:1:9-16 Computed imports are not allowed
+
+import "a" + "b"
+
+

testdata/import_failure_directory.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: read testdata: is a directory
+-------------------------------------------------
+	testdata/import_failure_directory:3:1-10	$
+
+import '.'
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/import_various_literals_escaped.golden

@@ -1 +1,5 @@
 testdata/".jsonnet:2:1 Unexpected end of file.
+
+
+
+

testdata/importstr_block_literal.golden

@@ -1 +1,7 @@
 testdata/importstr_block_literal:(1:11)-(3:4) Block string literals not allowed in imports
+
+importstr |||
+	block_literals_for_imports_are_not_allowed_and_make_exactly_zero_sense
+|||
+
+

testdata/importstr_computed.golden

@@ -1 +1,5 @@
 testdata/importstr_computed:1:12-19 Computed imports are not allowed
+
+importstr "a" + "b"
+
+

testdata/insuper2.golden

@@ -1 +1,5 @@
 testdata/insuper2:1:11-13 Expected token OPERATOR but got (in, "in")
+
+{ } { "x" in super }
+
+

testdata/insuper4.golden

@@ -1 +1,5 @@
 testdata/insuper4:1:2-13 Can't use super outside of an object.
+
+"x" in super
+
+

testdata/insuper6.golden

@@ -1 +1,5 @@
 testdata/insuper6:1:10-20 Unknown variable: undeclared
+
+{ assert undeclared in super }
+
+

testdata/lazy_operator2.golden

@@ -1 +1,15 @@
 RUNTIME ERROR: should happen
+-------------------------------------------------
+	testdata/lazy_operator2:1:9-29	$
+
+true && error "should happen"
+
+-------------------------------------------------
+	testdata/lazy_operator2:1:1-29	$
+
+true && error "should happen"
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/nonexistent_import.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Couldn't open import "no chance a file with this name exists": No match locally or in the Jsonnet library paths.
+-------------------------------------------------
+	testdata/nonexistent_import:1:1-50	$
+
+importstr 'no chance a file with this name exists'
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/nonexistent_import_crazy.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: Couldn't open import "ąęółńśćźż \" ' \n\n\t\t": No match locally or in the Jsonnet library paths.
+-------------------------------------------------
+	testdata/nonexistent_import_crazy:1:1-45	$
+
+importstr "ąęółńśćźż \" \' \n\n\t\t"
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/number_leading_zero.golden

@@ -1 +1,5 @@
 testdata/number_leading_zero:1:2-4 Did not expect: (NUMBER, "42")
+
+042
+
+

testdata/object_comp_assert.golden

@@ -1 +1,5 @@
 testdata/object_comp_assert:1:32-35 Object comprehension cannot have asserts.
+
+{ assert self.x == 5, ["x"]: 5 for i in [42] }
+
+

testdata/object_comp_bad_field.golden

@@ -1 +1,5 @@
 testdata/object_comp_bad_field:1:9-12 Object comprehensions can only have [e] fields.
+
+{ x: 42 for _ in [1] }
+
+

testdata/object_comp_bad_field2.golden

@@ -1 +1,5 @@
 testdata/object_comp_bad_field2:1:11-14 Object comprehensions can only have [e] fields.
+
+{ "x": 42 for _ in [1] }
+
+

testdata/object_comp_duplicate.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Duplicate field name: "x"
+-------------------------------------------------
+	<builtin>	builtin function <$objectFlatMerge>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/object_comp_err_elem.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/object_comp_err_elem:1:11-21	object <anonymous>
+
+{ ["x"]:  error "xxx" for x in [1] }
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_comp_err_index.golden

@@ -1 +1,13 @@
 RUNTIME ERROR: xxx
+-------------------------------------------------
+	testdata/object_comp_err_index:1:4-14	$
+
+{ [error "xxx"]: 42 for x in [1] }
+
+-------------------------------------------------
+	<builtin>	builtin function <$objectFlatMerge>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/object_comp_illegal.golden

@@ -1 +1,5 @@
 testdata/object_comp_illegal:1:15-18 Object comprehension can only have one field.
+
+{ local x = 5 for y in [1, 2, 3] }
+
+

testdata/object_comp_int_index.golden

@@ -1 +1,13 @@
 RUNTIME ERROR: Field name must be string, got number
+-------------------------------------------------
+	testdata/object_comp_int_index:1:1-30	$
+
+{ [x]: x for x in [1, 2, 3] }
+
+-------------------------------------------------
+	<builtin>	builtin function <$objectFlatMerge>
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/object_invariant10.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant11.golden

@@ -1 +1,13 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	testdata/object_invariant11:1:1-19	$
+
+{ assert false }.x
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/object_invariant13.golden

@@ -1 +1,10 @@
 RUNTIME ERROR: x
+-------------------------------------------------
+	testdata/object_invariant13:1:10-18	object <anonymous>
+
+{ assert error "x" }
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant14.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: xxx
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant2.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant7.golden

@@ -1 +1,34 @@
 RUNTIME ERROR: Field does not exist: x
+-------------------------------------------------
+	testdata/object_invariant7:1:16-21	object <anonymous>
+
+{ x: 5, assert super.x == 5 } 
+
+-------------------------------------------------
+	<std>:969:29-30	thunk from <thunk <ta> from <function <anonymous>>>
+
+        local ta = std.type(a);
+
+-------------------------------------------------
+	<builtin>	builtin function <type>
+
+-------------------------------------------------
+	<std>:971:33-35	thunk from <function <anonymous>>
+
+        if !std.primitiveEquals(ta, tb) then
+
+-------------------------------------------------
+	<builtin>	builtin function <primitiveEquals>
+
+-------------------------------------------------
+	<std>:971:12-40	function <anonymous>
+
+        if !std.primitiveEquals(ta, tb) then
+
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant8.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant9.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant_plus.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant_plus2.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: Object assertion failed.
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_invariant_plus6.golden

@@ -1 +1,8 @@
 RUNTIME ERROR: yyy
+-------------------------------------------------
+		
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/object_local.golden

@@ -0,0 +1,3 @@
+{
+   "baz": 42
+}

testdata/object_local.jsonnet

@@ -0,0 +1,2 @@
+{ local foo(bar) = bar, baz: foo(42) }
+