Use self for member access/assignment in all initializers, decoders, and encoders (#700)

### Motivation

In order to address #695 we made some targeted fixes (#696, #699) to use
explicit-self to avoid clashing with schema property names. This
addressed a clash with a specific variable with properties of only
certain schemas, but there are more places where we might encounter
future issues. Specifically, we have other variable names which might
cause a clash (e.g. `storage` and `discriminator`), and there are other
flavours of initializers, encoders, and decoders that were not updated
in the targeted fix.

In this PR, we update all access and assignment in the generated code
dealing with schemas to use explicit-self.


### Modifications

- Use self for member access and assignment in all initializers,
decoders, and encoders.
- Update the reference tests and snippet tests.

### Result

Removed some cases where valid OpenAPI docs would produce non-compiling
code.

### Test Plan

Snippet and reference tests. The latter is actually compiled during the
CI.

Author: simonjbeaumont

Sources/_OpenAPIGeneratorCore/Layers/StructuredSwiftRepresentation.swift

@@ -1354,6 +1354,16 @@ extension Expression {
     /// - Returns: A new expression representing member access with a dot prefix.
     static func dot(_ member: String) -> Self { Self.memberAccess(.init(right: member)) }
 
+    /// Returns a new member access expression with `self` as the receiver.
+    ///
+    /// For example: `self.foo`, where `member` is `foo`.
+    ///
+    /// - Parameter member: The name of the member to access on the expression.
+    /// - Returns: A new expression representing member access.
+    static func selfDot(_ member: String) -> Expression {
+        .memberAccess(.init(left: .identifier(.pattern("self")), right: member))
+    }
+
     /// Returns a new identifier expression for the provided pattern, such
     /// as a variable or function name.
     /// - Parameter name: The name of the identifier.
@@ -1555,6 +1565,7 @@ extension Expression {
     /// - Parameter expressions: The member expressions.
     /// - Returns: A tuple expression.
     static func tuple(_ expressions: [Expression]) -> Self { .tuple(.init(members: expressions)) }
+
 }
 
 extension MemberAccessDescription {

Sources/_OpenAPIGeneratorCore/Translator/CommonTranslations/translateCodable.swift

@@ -118,7 +118,7 @@ extension FileTranslator {
         let assignExprs: [Expression] = properties.map { property in
             let typeUsage = property.typeUsage
             return .assignment(
-                left: .identifierPattern("self").dot(property.swiftSafeName),
+                left: .selfDot(property.swiftSafeName),
                 right: .try(
                     .identifierPattern("container").dot("decode\(typeUsage.isOptional ? "IfPresent" : "")")
                         .call([
@@ -156,7 +156,7 @@ extension FileTranslator {
             .try(
                 .identifierPattern("container").dot("encode\(property.typeUsage.isOptional ? "IfPresent" : "")")
                     .call([
-                        .init(label: nil, expression: .identifierPattern("self").dot(property.swiftSafeName)),
+                        .init(label: nil, expression: .selfDot(property.swiftSafeName)),
                         .init(label: "forKey", expression: .dot(property.swiftSafeName)),
                     ])
             )
@@ -181,7 +181,7 @@ extension FileTranslator {
         let assignExprs: [Expression] = properties.map { property, isKeyValuePair in
             let decoderExpr: Expression =
                 isKeyValuePair ? .initFromDecoderExpr() : .decodeFromSingleValueContainerExpr()
-            return .assignment(left: .identifierPattern(property.swiftSafeName), right: .try(decoderExpr))
+            return .assignment(left: .selfDot(property.swiftSafeName), right: .try(decoderExpr))
         }
         return decoderInitializer(body: assignExprs.map { .expression($0) })
     }
@@ -194,12 +194,11 @@ extension FileTranslator {
     {
         let exprs: [Expression]
         if let firstSingleValue = properties.first(where: { !$0.isKeyValuePair }) {
-            let expr: Expression = .identifierPattern(firstSingleValue.property.swiftSafeName)
+            let expr: Expression = .selfDot(firstSingleValue.property.swiftSafeName)
                 .encodeToSingleValueContainerExpr(gracefully: false)
             exprs = [expr]
         } else {
-            exprs = properties.filter { $0.isKeyValuePair }.map(\.property.swiftSafeName)
-                .map { name in .identifierPattern(name).encodeExpr() }
+            exprs = properties.filter(\.isKeyValuePair).map { .selfDot($0.property.swiftSafeName).encodeExpr() }
         }
         return encoderFunction(body: exprs.map { .expression($0) })
     }
@@ -216,18 +215,15 @@ extension FileTranslator {
         let assignBlocks: [CodeBlock] = properties.map { (property, isKeyValuePair) in
             let decoderExpr: Expression =
                 isKeyValuePair ? .initFromDecoderExpr() : .decodeFromSingleValueContainerExpr()
-            let assignExpr: Expression = .assignment(
-                left: .identifierPattern(property.swiftSafeName),
-                right: .try(decoderExpr)
-            )
+            let assignExpr: Expression = .assignment(left: .selfDot(property.swiftSafeName), right: .try(decoderExpr))
             return .expression(assignExpr.wrapInDoCatchAppendArrayExpr())
         }
         let atLeastOneNotNilCheckExpr: Expression = .try(
             .identifierType(TypeName.decodingError).dot("verifyAtLeastOneSchemaIsNotNil")
                 .call([
                     .init(
                         label: nil,
-                        expression: .literal(.array(properties.map { .identifierPattern($0.property.swiftSafeName) }))
+                        expression: .literal(.array(properties.map { .selfDot($0.property.swiftSafeName) }))
                     ), .init(label: "type", expression: .identifierPattern("Self").dot("self")),
                     .init(label: "codingPath", expression: .identifierPattern("decoder").dot("codingPath")),
                     .init(label: "errors", expression: .identifierPattern("errors")),
@@ -250,14 +246,12 @@ extension FileTranslator {
             ? nil
             : .try(
                 .identifierPattern("encoder").dot("encodeFirstNonNilValueToSingleValueContainer")
-                    .call([
-                        .init(label: nil, expression: .literal(.array(singleValueNames.map { .identifierPattern($0) })))
-                    ])
+                    .call([.init(label: nil, expression: .literal(.array(singleValueNames.map { .selfDot($0) })))])
             )
         let encodeExprs: [Expression] =
             (encodeSingleValuesExpr.flatMap { [$0] } ?? [])
             + properties.filter { $0.isKeyValuePair }.map(\.property)
-            .map { property in .identifierPattern(property.swiftSafeName).optionallyChained().encodeExpr() }
+            .map { property in .selfDot(property.swiftSafeName).optionallyChained().encodeExpr() }
         return encoderFunction(body: encodeExprs.map { .expression($0) })
     }
 

Sources/_OpenAPIGeneratorCore/Translator/TypesTranslator/translateBoxedTypes.swift

@@ -107,10 +107,8 @@ extension TypesFileTranslator {
                 case .variable(var variableDescription) = commented
             else { return member }
             let name = TextBasedRenderer.renderedExpressionAsString(variableDescription.left)
-            variableDescription.getter = [.expression(.identifierPattern("storage").dot("value").dot(name))]
-            variableDescription.modify = [
-                .expression(.yield(.inOut(.identifierPattern("storage").dot("value").dot(name))))
-            ]
+            variableDescription.getter = [.expression(.selfDot("storage").dot("value").dot(name))]
+            variableDescription.modify = [.expression(.yield(.inOut(.selfDot("storage").dot("value").dot(name))))]
             return .commentable(comment, .variable(variableDescription))
         }
 
@@ -127,7 +125,7 @@ extension TypesFileTranslator {
             funcDesc.body = [
                 .expression(
                     .assignment(
-                        left: .identifierPattern("storage"),
+                        left: .selfDot("storage"),
                         right: .dot("init")
                             .call([
                                 .init(
@@ -167,7 +165,7 @@ extension TypesFileTranslator {
                 body: [
                     .expression(
                         .assignment(
-                            left: .identifierPattern("storage"),
+                            left: .selfDot("storage"),
                             right: .try(
                                 .dot("init").call([.init(label: "from", expression: .identifierPattern("decoder"))])
                             )
@@ -185,7 +183,7 @@ extension TypesFileTranslator {
                 body: [
                     .expression(
                         .try(
-                            .identifierPattern("storage").dot("encode")
+                            .selfDot("storage").dot("encode")
                                 .call([.init(label: "to", expression: .identifierPattern("encoder"))])
                         )
                     )