[CodeCompletion] Fix missing completions in type member access of right-hand side in generic where clause

Fixes the issue in #61064 (comment)

Author: ahoppen

lib/Parse/ParseGeneric.cpp

@@ -361,19 +361,29 @@ ParserStatus Parser::parseGenericWhereClause(
         SecondType = makeParserResult(ErrorTypeRepr::create(Context, PreviousLoc));
 
       // Add the requirement
+      //
+      // If the a type has a code completion token, don't record a same
+      // type constraint, because otherwise if we have
+      //   K.#^COMPLETE^# == Foo
+      // we parse this as
+      //   K == Foo
+      // and thus simplify K to Foo. But we didn't want to state that K is Foo
+      // but that K has a member of type Foo.
+      // FIXME: The proper way to fix this would be to represent the code
+      // completion token in the TypeRepr.
       if (FirstType.hasCodeCompletion()) {
-        // If the first type has a code completion token, don't record a same
-        // type constraint because otherwise if we have
-        //   K.#^COMPLETE^# == Foo
-        // we parse this as
-        //   K == Foo
-        // and thus simplify K to Foo. But we didn't want to state that K is Foo
-        // but that K has a member of type Foo.
-        // FIXME: The proper way to fix this would be to represent the code
-        // completion token in the TypeRepr.
+        SecondType = makeParserResult(
+            SecondType,
+            ErrorTypeRepr::create(Context, SecondType.get()->getLoc()));
+      }
+      if (SecondType.hasCodeCompletion()) {
+        FirstType = makeParserResult(
+            FirstType,
+            ErrorTypeRepr::create(Context, FirstType.get()->getLoc()));
+      }
+      if (FirstType.hasCodeCompletion() || SecondType.hasCodeCompletion()) {
         Requirements.push_back(RequirementRepr::getTypeConstraint(
-            FirstType.get(), EqualLoc,
-            ErrorTypeRepr::create(Context, SecondType.get()->getLoc()),
+            FirstType.get(), EqualLoc, SecondType.get(),
             isRequirementExpansion));
       } else {
         Requirements.push_back(RequirementRepr::getSameType(

test/IDE/complete_where_clause.swift

@@ -39,7 +39,7 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=NOMINAL_TYPEALIAS_NESTED1_EXT | %FileCheck %s -check-prefix=NOMINAL_TYPEALIAS_NESTED1_EXT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=NOMINAL_TYPEALIAS_NESTED2_EXT | %FileCheck %s -check-prefix=NOMINAL_TYPEALIAS_NESTED2_EXT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=EXT_ASSOC_MEMBER_1 | %FileCheck %s -check-prefix=EXT_ASSOC_MEMBER
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=EXT_ASSOC_MEMBER_2 | %FileCheck %s -check-prefix=EXT_ASSOC_MEMBER_2
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=EXT_ASSOC_MEMBER_2 | %FileCheck %s -check-prefix=EXT_ASSOC_MEMBER
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=EXT_SECONDTYPE | %FileCheck %s -check-prefix=EXT_SECONDTYPE
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=WHERE_CLAUSE_WITH_EQUAL | %FileCheck %s -check-prefix=WHERE_CLAUSE_WITH_EQUAL
 
@@ -234,11 +234,8 @@ extension WithAssoc where T.#^EXT_ASSOC_MEMBER_1^#
 // EXT_ASSOC_MEMBER-DAG: Decl[AssociatedType]/CurrNominal:   Q;
 // EXT_ASSOC_MEMBER-DAG: Keyword/None:                       Type[#Self.T.Type#];
 
-// This is kind of funny because we parse it as 'Int == T', so completing 'T'
-// shows members of 'Int'.
 extension WithAssoc where Int == T.#^EXT_ASSOC_MEMBER_2^# 
-// EXT_ASSOC_MEMBER_2: Begin completions, {{.*}} items
-// EXT_ASSOC_MEMBER_2: Keyword/None:                           Type[#Int.Type#];
+// Same as EXT_ASSOC_MEMBER
 
 extension WithAssoc where Int == #^EXT_SECONDTYPE^# 
 // EXT_SECONDTYPE-DAG: Decl[AssociatedType]/CurrNominal:   T;