Add editor place holder type

Author: kimdv

Sources/SwiftParser/Types.swift

@@ -938,7 +938,9 @@ extension Parser {
 
 extension Parser {
   mutating func parseResultType() -> RawTypeSyntax {
-    if self.at(prefix: "<") {
+    if self.currentToken.isEditorPlaceholder {
+      return self.parseTypeIdentifier()
+    } else if self.at(prefix: "<") {
       let generics = self.parseGenericParameters()
       let baseType = self.parseType()
       return RawTypeSyntax(

Tests/SwiftParserTest/LexerTests.swift

@@ -846,6 +846,16 @@ public class LexerTests: ParserTestCase {
         LexemeSpec(.identifier, text: "<##>", trailing: "", diagnostic: "editor placeholder in source file")
       ]
     )
+
+    assertLexemes(
+      "let 1️⃣<#name#> = 2️⃣<#value#>",
+      lexemes: [
+        LexemeSpec(.keyword, text: "let", trailing: " "),
+        LexemeSpec(.identifier, text: "<#name#>", trailing: " ", errorLocationMarker: "1️⃣", diagnostic: "editor placeholder in source file"),
+        LexemeSpec(.equal, text: "=", trailing: " "),
+        LexemeSpec(.identifier, text: "<#value#>", errorLocationMarker: "2️⃣", diagnostic: "editor placeholder in source file"),
+      ]
+    )
   }
 
   func testCommentAttribution() {

Tests/SwiftParserTest/TypeTests.swift

@@ -216,4 +216,92 @@ final class TypeTests: ParserTestCase {
       substructureAfterMarker: "1️⃣"
     )
   }
+
+  func testTypeWithPlaceholder() {
+    assertParse(
+      "let a: 1️⃣<#T#> = x",
+      substructure: VariableDeclSyntax(
+        bindingSpecifier: .keyword(.let),
+        bindings: [
+          PatternBindingSyntax(
+            pattern: IdentifierPatternSyntax(identifier: .identifier("a")),
+            typeAnnotation: TypeAnnotationSyntax(
+              type: IdentifierTypeSyntax(
+                name: .identifier("<#T#>")
+              )
+            ),
+            initializer: InitializerClauseSyntax(
+              value: DeclReferenceExprSyntax(
+                baseName: .identifier("x")
+              )
+            )
+          )
+        ]
+      ),
+      diagnostics: [
+        DiagnosticSpec(message: "editor placeholder in source file")
+      ]
+    )
+
+    assertParse(
+      "let a: 1️⃣<#T#><Foo> = x",
+      substructure: VariableDeclSyntax(
+        bindingSpecifier: .keyword(.let),
+        bindings: [
+          PatternBindingSyntax(
+            pattern: IdentifierPatternSyntax(identifier: .identifier("a")),
+            typeAnnotation: TypeAnnotationSyntax(
+              type: IdentifierTypeSyntax(
+                name: .identifier("<#T#>"),
+                genericArgumentClause: GenericArgumentClauseSyntax(
+                  arguments: GenericArgumentListSyntax([
+                    GenericArgumentSyntax(
+                      argument: IdentifierTypeSyntax(
+                        name: .identifier("Foo")
+                      )
+                    )
+                  ])
+                )
+              )
+            ),
+            initializer: InitializerClauseSyntax(
+              value: DeclReferenceExprSyntax(
+                baseName: .identifier("x")
+              )
+            )
+          )
+        ]
+      ),
+      diagnostics: [
+        DiagnosticSpec(message: "editor placeholder in source file")
+      ]
+    )
+
+    assertParse(
+      "let a: [1️⃣<#T#>] = x",
+      substructure: VariableDeclSyntax(
+        bindingSpecifier: .keyword(.let),
+        bindings: [
+          PatternBindingSyntax(
+            pattern: IdentifierPatternSyntax(identifier: .identifier("a")),
+            typeAnnotation: TypeAnnotationSyntax(
+              type: ArrayTypeSyntax(
+                element: IdentifierTypeSyntax(
+                  name: .identifier("<#T#>")
+                )
+              )
+            ),
+            initializer: InitializerClauseSyntax(
+              value: DeclReferenceExprSyntax(
+                baseName: .identifier("x")
+              )
+            )
+          )
+        ]
+      ),
+      diagnostics: [
+        DiagnosticSpec(message: "editor placeholder in source file")
+      ]
+    )
+  }
 }