Improve error reporting when reading bad metadata during EnC

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -5876,7 +5876,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>Local function '{0}' must declare a body because it is not marked 'static extern'.</value>
   </data>
   <data name="ERR_InvalidDebugInfo" xml:space="preserve">
-    <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}'</value>
+    <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}': {3}</value>
   </data>
   <data name="IConversionExpressionIsNotCSharpConversion" xml:space="preserve">
     <value>{0} is not a valid C# conversion expression</value>

src/Compilers/CSharp/Test/Emit2/Emit/EditAndContinue/EditAndContinueTests.cs

@@ -12760,52 +12760,35 @@ public void ManyGenerations()
             }
         }
 
+        [Theory]
+        [InlineData(typeof(IOException))]
+        [InlineData(typeof(BadImageFormatException))]
+        [InlineData(typeof(InvalidDataException))]
         [WorkItem(187868, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/187868")]
-        [Fact]
-        public void PdbReadingErrors()
+        public void SymReaderErrors(Type exceptionType)
         {
-            var source0 = MarkedSource(@"
-using System;
-
-class C
-{
-	static void F() 
-    {
-        <N:0>Console.WriteLine(1);</N:0>
-    }
-}");
-
-            var source1 = MarkedSource(@"
-using System;
-
-class C
-{
-	static void F() 
-    {
-        <N:0>Console.WriteLine(2);</N:0>
-    }
-}");
-            var compilation0 = CreateCompilation(source0.Tree, options: TestOptions.DebugDll, assemblyName: "PdbReadingErrorsAssembly");
-            var compilation1 = compilation0.WithSource(source1.Tree);
-
-            var v0 = CompileAndVerify(compilation0);
-            var md0 = ModuleMetadata.CreateFromImage(v0.EmittedAssemblyData);
-
-            var f0 = compilation0.GetMember<MethodSymbol>("C.F");
-            var f1 = compilation1.GetMember<MethodSymbol>("C.F");
-
-            var generation0 = CreateInitialBaseline(compilation0, md0, methodHandle =>
-            {
-                throw new InvalidDataException("Bad PDB!");
-            });
-
-            var diff1 = compilation1.EmitDifference(
-                generation0,
-                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, f0, f1, GetSyntaxMapFromMarkers(source0, source1))));
-
-            diff1.EmitResult.Diagnostics.Verify(
-                // (6,14): error CS7038: Failed to emit module 'Unable to read debug information of method 'C.F()' (token 0x06000001) from assembly 'PdbReadingErrorsAssembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null''.
-                Diagnostic(ErrorCode.ERR_InvalidDebugInfo, "F").WithArguments("C.F()", "100663297", "PdbReadingErrorsAssembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null").WithLocation(6, 14));
+            using var _ = new EditAndContinueTest(assemblyName: "test")
+                .AddBaseline(
+                    """
+                    class C { void F() { int x = 1; } }
+                    """,
+                    debugInformationProvider: _ => throw (Exception)Activator.CreateInstance(exceptionType, ["bug!"]))
+                .AddGeneration(
+                    // 1
+                    """
+                    class C { void F() { int x = 2; } }
+                    """,
+                    edits:
+                    [
+                        Edit(SemanticEditKind.Update, c => c.GetMember("C.F"), preserveLocalVariables: true)
+                    ],
+                    expectedErrors:
+                    [
+                        // (1,16): error CS7103: Unable to read debug information of method 'C.F()' (token 0x06000001) from assembly 'test, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null': bug!
+                        // class C { void F() { int x = 2; } }
+                        Diagnostic(ErrorCode.ERR_InvalidDebugInfo, "F").WithArguments("C.F()", "100663297", "test, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null", "bug!").WithLocation(1, 16)
+                    ])
+                .Verify();
         }
 
         [Fact]
@@ -12846,7 +12829,7 @@ static void F()
                 throw new ArgumentOutOfRangeException();
             });
 
-            // the compiler should't swallow any exceptions but InvalidDataException
+            // the compiler should't swallow any exceptions but InvalidDataException, IOException and BadImageFormatException
             Assert.Throws<ArgumentOutOfRangeException>(() =>
                 compilation1.EmitDifference(
                     generation0,

src/Compilers/Core/Portable/Emit/EditAndContinue/DefinitionMap.cs

@@ -291,14 +291,15 @@ protected abstract void GetStateMachineFieldMapFromMetadata(
                     debugInfo = Baseline.DebugInformationProvider(methodHandle);
                     localSignature = Baseline.LocalSignatureProvider(methodHandle);
                 }
-                catch (Exception e) when (e is InvalidDataException or IOException)
+                catch (Exception e) when (e is InvalidDataException or IOException or BadImageFormatException)
                 {
                     diagnostics.Add(MessageProvider.CreateDiagnostic(
                         MessageProvider.ERR_InvalidDebugInfo,
                         method.Locations.First(),
                         method,
                         MetadataTokens.GetToken(methodHandle),
-                        method.ContainingAssembly
+                        method.ContainingAssembly,
+                        e.Message
                     ));
 
                     return null;
@@ -382,7 +383,8 @@ protected abstract void GetStateMachineFieldMapFromMetadata(
                             method.Locations.First(),
                             method,
                             MetadataTokens.GetToken(localSignature),
-                            method.ContainingAssembly
+                            method.ContainingAssembly,
+                            e.Message
                         ));
 
                         return null;
@@ -690,7 +692,7 @@ static ImmutableArray<string> getHoistedVariableNames(ImmutableArray<ISymbolInte
             {
                 provider = Baseline.DebugInformationProvider(MetadataTokens.MethodDefinitionHandle(methodRowId));
             }
-            catch (Exception e) when (e is InvalidDataException or IOException)
+            catch (Exception e) when (e is InvalidDataException or IOException or BadImageFormatException)
             {
                 return [];
             }

src/Compilers/VisualBasic/Portable/VBResources.resx

@@ -5541,7 +5541,7 @@
     <value>Type is for evaluation purposes only and is subject to change or removal in future updates.</value>
   </data>
   <data name="ERR_InvalidDebugInfo" xml:space="preserve">
-    <value>Unable to read debug information of method '{0}' (token 0x{1}) from assembly '{2}'</value>
+    <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}': {3}</value>
   </data>
   <data name="IConversionExpressionIsNotVisualBasicConversion" xml:space="preserve">
     <value>{0} is not a valid Visual Basic conversion expression</value>