From acf6da7a722ac3dc870a011ec01a404093df397d Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Tue, 13 Aug 2019 15:37:58 -0700
Subject: [PATCH] Add slightly modified example from #25413

---
 src/compiler/checker.ts                       |  4 +--
 ...conditionalTypeSubclassExtendsTypeParam.js |  9 ++++++
 ...tionalTypeSubclassExtendsTypeParam.symbols | 28 +++++++++++++++++++
 ...ditionalTypeSubclassExtendsTypeParam.types | 11 ++++++++
 ...conditionalTypeSubclassExtendsTypeParam.ts |  6 ++++
 5 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.js
 create mode 100644 tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.symbols
 create mode 100644 tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.types
 create mode 100644 tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index ebda82615bfc5..ee640ec2d7211 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13495,9 +13495,9 @@ namespace ts {
 
                     // TODO: Find a nice way to include potential conditional type breakdowns in error output, if those seems good (they usually don't)
                     let localResult: Ternary | undefined;
-                    if (skipTrue || (localResult = isRelatedTo(source, instantiateType(c.trueType, distributionMapper), /*reportErrors*/ false))) {
+                    if (skipTrue || (localResult = isRelatedTo(source, instantiateType(getTrueTypeFromConditionalType(c), distributionMapper), /*reportErrors*/ false))) {
                         if (!skipFalse) {
-                            localResult = (localResult || Ternary.Maybe) & isRelatedTo(source, instantiateType(c.falseType, distributionMapper), /*reportErrors*/ false);
+                            localResult = (localResult || Ternary.Maybe) & isRelatedTo(source, instantiateType(getFalseTypeFromConditionalType(c), distributionMapper), /*reportErrors*/ false);
                         }
                     }
                     if (localResult) {
diff --git a/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.js b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.js
new file mode 100644
index 0000000000000..e2334e631b206
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.js
@@ -0,0 +1,9 @@
+//// [conditionalTypeSubclassExtendsTypeParam.ts]
+declare class Model<M extends MR, MR extends {}> {
+    public getField2<K extends keyof M>(): Field<M[K], [K] extends [keyof MR] ? MR[K] : M[K]>
+}
+
+declare class Field<T extends TR, TR> {
+}
+
+//// [conditionalTypeSubclassExtendsTypeParam.js]
diff --git a/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.symbols b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.symbols
new file mode 100644
index 0000000000000..a2c25631171dd
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.symbols
@@ -0,0 +1,28 @@
+=== tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts ===
+declare class Model<M extends MR, MR extends {}> {
+>Model : Symbol(Model, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 0))
+>M : Symbol(M, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 20))
+>MR : Symbol(MR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 33))
+>MR : Symbol(MR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 33))
+
+    public getField2<K extends keyof M>(): Field<M[K], [K] extends [keyof MR] ? MR[K] : M[K]>
+>getField2 : Symbol(Model.getField2, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 50))
+>K : Symbol(K, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 1, 21))
+>M : Symbol(M, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 20))
+>Field : Symbol(Field, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 2, 1))
+>M : Symbol(M, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 20))
+>K : Symbol(K, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 1, 21))
+>K : Symbol(K, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 1, 21))
+>MR : Symbol(MR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 33))
+>MR : Symbol(MR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 33))
+>K : Symbol(K, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 1, 21))
+>M : Symbol(M, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 0, 20))
+>K : Symbol(K, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 1, 21))
+}
+
+declare class Field<T extends TR, TR> {
+>Field : Symbol(Field, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 2, 1))
+>T : Symbol(T, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 4, 20))
+>TR : Symbol(TR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 4, 33))
+>TR : Symbol(TR, Decl(conditionalTypeSubclassExtendsTypeParam.ts, 4, 33))
+}
diff --git a/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.types b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.types
new file mode 100644
index 0000000000000..63a3834c2a364
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypeSubclassExtendsTypeParam.types
@@ -0,0 +1,11 @@
+=== tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts ===
+declare class Model<M extends MR, MR extends {}> {
+>Model : Model<M, MR>
+
+    public getField2<K extends keyof M>(): Field<M[K], [K] extends [keyof MR] ? MR[K] : M[K]>
+>getField2 : <K extends keyof M>() => Field<M[K], [K] extends [keyof MR] ? MR[K] : M[K]>
+}
+
+declare class Field<T extends TR, TR> {
+>Field : Field<T, TR>
+}
diff --git a/tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts b/tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts
new file mode 100644
index 0000000000000..31bd6c6b81818
--- /dev/null
+++ b/tests/cases/compiler/conditionalTypeSubclassExtendsTypeParam.ts
@@ -0,0 +1,6 @@
+declare class Model<M extends MR, MR extends {}> {
+    public getField2<K extends keyof M>(): Field<M[K], [K] extends [keyof MR] ? MR[K] : M[K]>
+}
+
+declare class Field<T extends TR, TR> {
+}
\ No newline at end of file