Promote visibility of members in all templates

We were only promoting members in templates whose declaring types explicitly specified a visibility modifier.
Fixes #457

Author: AArnott

src/Microsoft.Windows.CsWin32/Generator.cs

@@ -3707,19 +3707,20 @@ private MemberDeclarationSyntax ElevateVisibility(MemberDeclarationSyntax member
         {
             if (this.Visibility == SyntaxKind.PublicKeyword)
             {
-                int indexOfInternal = member.Modifiers.IndexOf(SyntaxKind.InternalKeyword);
+                MemberDeclarationSyntax publicMember = member;
+                int indexOfInternal = publicMember.Modifiers.IndexOf(SyntaxKind.InternalKeyword);
                 if (indexOfInternal >= 0)
                 {
-                    MemberDeclarationSyntax publicMember = member.WithModifiers(member.Modifiers.Replace(member.Modifiers[indexOfInternal], TokenWithSpace(this.Visibility)));
-
-                    // Apply change recursively.
-                    if (publicMember is TypeDeclarationSyntax memberContainer)
-                    {
-                        publicMember = memberContainer.WithMembers(List(memberContainer.Members.Select(this.ElevateVisibility)));
-                    }
+                    publicMember = publicMember.WithModifiers(publicMember.Modifiers.Replace(publicMember.Modifiers[indexOfInternal], TokenWithSpace(this.Visibility)));
+                }
 
-                    return publicMember;
+                // Apply change recursively.
+                if (publicMember is TypeDeclarationSyntax memberContainer)
+                {
+                    publicMember = memberContainer.WithMembers(List(memberContainer.Members.Select(this.ElevateVisibility)));
                 }
+
+                return publicMember;
             }
 
             return member;

test/Microsoft.Windows.CsWin32.Tests/GeneratorTests.cs

@@ -118,6 +118,45 @@ public void SimplestMethod(string tfm)
         }
     }
 
+    [Theory]
+    [PairwiseData]
+    public void TemplateProvidedMembersMatchVisibilityWithContainingType_Methods(bool generatePublic)
+    {
+        this.generator = this.CreateGenerator(new GeneratorOptions { Public = generatePublic });
+        Assert.True(this.generator.TryGenerate("HRESULT", CancellationToken.None));
+        this.CollectGeneratedCode(this.generator);
+        this.AssertNoDiagnostics();
+
+        MethodDeclarationSyntax? generatedMethod = this.FindGeneratedMethod("ThrowOnFailure").Single();
+        SyntaxKind expectedVisibility = generatePublic ? SyntaxKind.PublicKeyword : SyntaxKind.InternalKeyword;
+        Assert.True(generatedMethod.Modifiers.Any(expectedVisibility));
+    }
+
+    [Theory]
+    [PairwiseData]
+    public void TemplateProvidedMembersMatchVisibilityWithContainingType_OtherMemberTypes(bool generatePublic)
+    {
+        this.generator = this.CreateGenerator(new GeneratorOptions { Public = generatePublic });
+        Assert.True(this.generator.TryGenerate("PCSTR", CancellationToken.None));
+        this.CollectGeneratedCode(this.generator);
+        this.AssertNoDiagnostics();
+
+        StructDeclarationSyntax? pcstrType = (StructDeclarationSyntax?)this.FindGeneratedType("PCSTR").Single();
+        SyntaxKind expectedVisibility = generatePublic ? SyntaxKind.PublicKeyword : SyntaxKind.InternalKeyword;
+
+        // Assert fields
+        Assert.Contains(pcstrType?.Members.OfType<FieldDeclarationSyntax>(), f => f.Declaration.Variables.Any(v => v.Identifier.ValueText == "Value") && f.Modifiers.Any(expectedVisibility));
+
+        // Assert properties
+        Assert.Contains(pcstrType?.Members.OfType<PropertyDeclarationSyntax>(), p => p.Identifier.ValueText == "Length" && p.Modifiers.Any(expectedVisibility));
+
+        // Assert constructors
+        Assert.All(pcstrType?.Members.OfType<ConstructorDeclarationSyntax>(), c => c.Modifiers.Any(expectedVisibility));
+
+        // Assert that private members remain private.
+        Assert.Contains(pcstrType?.Members.OfType<PropertyDeclarationSyntax>(), p => p.Identifier.ValueText == "DebuggerDisplay" && p.Modifiers.Any(SyntaxKind.PrivateKeyword));
+    }
+
     [Fact]
     public void SupportedOSPlatform_AppearsOnFriendlyOverloads()
     {