#1663: Add various safe-guards against unintended use to Language and SolutionWriter.

ILSpy/Languages/ILLanguage.cs

@@ -16,6 +16,7 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+using System;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.Linq;
@@ -165,6 +166,11 @@ namespace ICSharpCode.ILSpy
 			var metadata = module.Metadata;
 			var dis = CreateDisassembler(output, options);
 
+			if (options.FullDecompilation && options.SaveAsProjectDirectory != null)
+			{
+				throw new NotSupportedException($"Language '{Name}' does not support exporting assemblies as projects!");
+			}
+
 			// don't automatically load additional assemblies when an assembly node is selected in the tree view
 			using (options.FullDecompilation ? null : LoadedAssembly.DisableAssemblyLoad(assembly.AssemblyList))
 			{

ILSpy/Languages/Language.cs

@@ -130,6 +130,10 @@ namespace ICSharpCode.ILSpy
 			var asm = assembly.GetPEFileOrNull();
 			if (asm == null)
 				return null;
+			if (options.FullDecompilation && options.SaveAsProjectDirectory != null)
+			{
+				throw new NotSupportedException($"Language '{Name}' does not support exporting assemblies as projects!");
+			}
 			var metadata = asm.Metadata;
 			if (metadata.IsAssembly)
 			{

ILSpy/SolutionWriter.cs

@@ -113,9 +113,17 @@ namespace ICSharpCode.ILSpy
 					n => WriteProject(n, language, solutionDirectory, ct)))
 					.ConfigureAwait(false);
 
+				if (projects.Count == 0)
+				{
+					result.WriteLine();
+					result.WriteLine("Solution could not be created, because none of the selected assemblies could be decompiled into a project.");
+				}
+				else
+				{
 					await Task.Run(() => SolutionCreator.WriteSolutionFile(solutionFilePath, projects))
 						.ConfigureAwait(false);
 				}
+			}
 			catch (AggregateException ae)
 			{
 				if (ae.Flatten().InnerExceptions.All(e => e is OperationCanceledException))
@@ -167,8 +175,23 @@ namespace ICSharpCode.ILSpy
 		void WriteProject(LoadedAssembly loadedAssembly, Language language, string targetDirectory, CancellationToken ct)
 		{
 			targetDirectory = Path.Combine(targetDirectory, loadedAssembly.ShortName);
+
+			if (language.ProjectFileExtension == null)
+			{
+				statusOutput.Add("-------------");
+				statusOutput.Add($"Language '{language.Name}' does not support exporting assemblies as projects!");
+				return;
+			}
+
 			string projectFileName = Path.Combine(targetDirectory, loadedAssembly.ShortName + language.ProjectFileExtension);
 
+			if (File.Exists(targetDirectory))
+			{
+				statusOutput.Add("-------------");
+				statusOutput.Add($"Failed to create a directory '{targetDirectory}':{Environment.NewLine}A file with the same name already exists!");
+				return;
+			}
+
 			if (!Directory.Exists(targetDirectory))
 			{
 				try
@@ -177,6 +200,7 @@ namespace ICSharpCode.ILSpy
 				}
 				catch (Exception e)
 				{
+					statusOutput.Add("-------------");
 					statusOutput.Add($"Failed to create a directory '{targetDirectory}':{Environment.NewLine}{e}");
 					return;
 				}
@@ -200,8 +224,14 @@ namespace ICSharpCode.ILSpy
 					}
 				}
 			}
+			catch (NotSupportedException e)
+			{
+				statusOutput.Add("-------------");
+				statusOutput.Add($"Failed to decompile the assembly '{loadedAssembly.FileName}':{Environment.NewLine}{e.Message}");
+			}
 			catch (Exception e) when (!(e is OperationCanceledException))
 			{
+				statusOutput.Add("-------------");
 				statusOutput.Add($"Failed to decompile the assembly '{loadedAssembly.FileName}':{Environment.NewLine}{e}");
 			}
 		}