Increase coverage of crash reporting.

pkg/front_end/lib/src/fasta/fasta.dart

Index: pkg/front_end/lib/src/fasta/fasta.dart
diff --git a/pkg/front_end/lib/src/fasta/fasta.dart b/pkg/front_end/lib/src/fasta/fasta.dart
index 97d155c45ef47fe48737c21df3cb5c3ad3d86dbd..424cfcc58cca473debf697d6f30133dd23b3f72a 100644
--- a/pkg/front_end/lib/src/fasta/fasta.dart
+++ b/pkg/front_end/lib/src/fasta/fasta.dart
@@ -8,7 +8,7 @@ import 'dart:async' show Future;
 
 import 'dart:convert' show JSON;
 
-import 'dart:io' show BytesBuilder, FileSystemEntity, exitCode;
+import 'dart:io' show BytesBuilder, Directory, File, exitCode;
 
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
 
@@ -22,7 +22,7 @@ import 'compiler_command_line.dart' show CompilerCommandLine;
 
 import 'compiler_context.dart' show CompilerContext;
 
-import 'errors.dart' show InputError, inputError;
+import 'errors.dart' show InputError, formatUnexpected, inputError, reportCrash;
 
 import 'kernel/kernel_target.dart' show KernelTarget;
 
@@ -166,44 +166,50 @@ class CompileTask {
 
 Future<CompilationResult> parseScript(
     Uri fileName, Uri packages, Uri patchedSdk, bool verbose) async {
-  if (!FileSystemEntity.isFileSync(fileName.toFilePath())) {
-    throw "Input file '${fileName.toFilePath()}' does not exist.";
-  }
-
-  if (!FileSystemEntity.isDirectorySync(patchedSdk.toFilePath())) {
-    throw "Patched sdk directory not found at ${patchedSdk.toFilePath()}";
-  }
-
-  Target target = getTarget("vm", new TargetFlags(strongMode: false));
-
-  Program program;
-  final uriTranslator = await TranslateUri.parse(null, packages);
-  final Ticker ticker = new Ticker(isVerbose: verbose);
-  final DillTarget dillTarget = new DillTarget(ticker, uriTranslator);
-  dillTarget.read(patchedSdk.resolve('platform.dill'));
-  final KernelTarget kernelTarget = new KernelTarget(dillTarget, uriTranslator);
   try {
-    kernelTarget.read(fileName);
-    await dillTarget.writeOutline(null);
-    program = await kernelTarget.writeOutline(null);
-    program = await kernelTarget.writeProgram(null);
-    if (kernelTarget.errors.isNotEmpty) {
-      return new CompilationResult.errors(kernelTarget.errors
-          .map((err) => err.toString())
-          .toList(growable: false));
+    if (!await new File.fromUri(fileName).exists()) {
+      return new CompilationResult.error(
+          formatUnexpected(fileName, -1, "No such file."));
+    }
+    if (!await new Directory.fromUri(patchedSdk).exists()) {
+      return new CompilationResult.error(
+          formatUnexpected(patchedSdk, -1, "Patched sdk directory not found."));
+    }
+
+    Target target = getTarget("vm", new TargetFlags(strongMode: false));
+
+    Program program;
+    final uriTranslator = await TranslateUri.parse(null, packages);
+    final Ticker ticker = new Ticker(isVerbose: verbose);
+    final DillTarget dillTarget = new DillTarget(ticker, uriTranslator);
+    dillTarget.read(patchedSdk.resolve('platform.dill'));
+    final KernelTarget kernelTarget =
+        new KernelTarget(dillTarget, uriTranslator);
+    try {
+      kernelTarget.read(fileName);
+      await dillTarget.writeOutline(null);
+      program = await kernelTarget.writeOutline(null);
+      program = await kernelTarget.writeProgram(null);
+      if (kernelTarget.errors.isNotEmpty) {
+        return new CompilationResult.errors(kernelTarget.errors
+            .map((err) => err.toString())
+            .toList(growable: false));
+      }
+    } on InputError catch (e) {
+      return new CompilationResult.error(e.format());
     }
-  } on InputError catch (e) {
-    return new CompilationResult.error(e.format());
-  }
 
-  // Perform target-specific transformations.
-  target.performModularTransformations(program);
-  target.performGlobalTransformations(program);
+    // Perform target-specific transformations.
+    target.performModularTransformations(program);
+    target.performGlobalTransformations(program);
 
-  // Write the program to a list of bytes and return it.
-  var sink = new ByteSink();
-  new BinaryPrinter(sink).writeProgramFile(program);
-  return new CompilationResult.ok(sink.builder.takeBytes());
+    // Write the program to a list of bytes and return it.
+    var sink = new ByteSink();
+    new BinaryPrinter(sink).writeProgramFile(program);
+    return new CompilationResult.ok(sink.builder.takeBytes());
+  } catch (e, s) {
+    return reportCrash(e, s, fileName);
+  }
 }
 
 // TODO(ahe): https://github.com/dart-lang/sdk/issues/28316