Fix comparable in switch

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

src/compiler/checker.ts

@@ -16883,6 +16883,7 @@ namespace ts {
  let hasDuplicateDefaultClause = false;
 
  const expressionType = checkExpression(node.expression);
+ const expressionIsLiteral = isLiteralType(expressionType);
  forEach(node.caseBlock.clauses, clause => {
  // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
  if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,10 +16904,16 @@ namespace ts {
  // TypeScript 1.0 spec (April 2014): 5.9
  // In a 'switch' statement, each 'case' expression must be of a type that is comparable
  // to or from the type of the 'switch' expression.
- const caseType = checkExpression(caseClause.expression);
- if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+ let caseType = checkExpression(caseClause.expression);
+ const caseIsLiteral = isLiteralType(caseType);
+ let comparedExpressionType = expressionType;
+ if (!caseIsLiteral || !expressionIsLiteral) {
+ caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+ comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+ }
+ if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
  // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
- checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+ checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
  }
  }
  forEach(clause.statements, checkSourceElement);

tests/baselines/reference/switchAssignmentCompat.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
  switch (0) {
  case Foo: break; // Error expected
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  }
 

tests/baselines/reference/switchCaseCircularRefeference.errors.txt

@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
- Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+ Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
  switch (x.a) {
  case x:
  ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
  break;
  }
  }

tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
@@ -10,11 +10,11 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  switch (0) {
  case Foo: break; // Error
  ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
  case "sss": break; // Error
  ~~~~~
 !!! error TS2678: Type '"sss"' is not comparable to type '0'.
- case 123: break; // No Error
+ case 123: break; // Error
  ~~~
 !!! error TS2678: Type '123' is not comparable to type '0'.
  case true: break; // Error
@@ -30,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
  case "sss": break;
  case 123: break;
  case true: break;
- }
+ }
+

tests/baselines/reference/switchCasesExpressionTypeMismatch.js

@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 var s = 0;

tests/baselines/reference/switchComparableCompatForBrands.js

@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+ function MyBrand() {
+ }
+ return MyBrand;
+}());
+function test(strInput) {
+ switch (strInput) {
+ case "a":
+ return 1;
+ }
+ return 0;
+}

tests/baselines/reference/switchComparableCompatForBrands.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+ private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+ switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}
+

tests/baselines/reference/switchComparableCompatForBrands.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+ private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+ switch(strInput)
+>strInput : string & MyBrand
+ {
+ case "a":
+>"a" : "a"
+
+ return 1;
+>1 : 1
+ }
+ return 0;
+>0 : 0
+}
+

tests/cases/compiler/switchCasesExpressionTypeMismatch.ts

@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
  case Foo: break; // Error
  case "sss": break; // Error
- case 123: break; // No Error
+ case 123: break; // Error
  case true: break; // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
  case "sss": break;
  case 123: break;
  case true: break;
-}
+}

tests/cases/compiler/switchComparableCompatForBrands.ts

@@ -0,0 +1,13 @@
+class MyBrand
+{
+ private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+ switch(strInput)
+ {
+ case "a":
+ return 1;
+ }
+ return 0;
+}