Merge pull request #20883 from HerringtonDarkholme/relax-type-constraint

fix #20018, allow skip constraint when merging interfaces
microsoft · Jan 5, 2018 · ed5e624 · ed5e624
2 parents 67eabb9 + 303786a
commit ed5e624
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Showing 6 changed files with 179 additions and 7 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -22642,9 +22642,11 @@ namespace ts {
                     // type parameter at this position, we report an error.
                     const sourceConstraint = source.constraint && getTypeFromTypeNode(source.constraint);
                     const targetConstraint = getConstraintFromTypeParameter(target);
-                    if ((sourceConstraint || targetConstraint) &&
-                        (!sourceConstraint || !targetConstraint || !isTypeIdenticalTo(sourceConstraint, targetConstraint))) {
-                        return false;
+                    if (sourceConstraint) {
+                        // relax check if later interface augmentation has no constraint
+                        if (!targetConstraint || !isTypeIdenticalTo(sourceConstraint, targetConstraint)) {
+                            return false;
+                        }
                     }
 
                     // If the type parameter node has a default and it is not identical to the default

diff --git a/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.errors.txt b/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.errors.txt
@@ -4,9 +4,11 @@ tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDi
 tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts(14,15): error TS2428: All declarations of 'B' must have identical type parameters.
 tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts(32,22): error TS2428: All declarations of 'A' must have identical type parameters.
 tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts(38,22): error TS2428: All declarations of 'A' must have identical type parameters.
+tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts(53,11): error TS2428: All declarations of 'C' must have identical type parameters.
+tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts(57,11): error TS2428: All declarations of 'C' must have identical type parameters.
 
 
-==== tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts (6 errors) ====
+==== tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts (8 errors) ====
     interface A<T extends Date> {
               ~
 !!! error TS2428: All declarations of 'A' must have identical type parameters.
@@ -59,4 +61,29 @@ tests/cases/conformance/interfaces/declarationMerging/twoGenericInterfacesWithDi
 !!! error TS2428: All declarations of 'A' must have identical type parameters.
             y: T;
         }
-    }
+    }
+
+    interface B<T extends number> {
+      u: T;
+      v: Constraint<T>; // ok
+    }
+
+    interface B<T> { // ok
+      x: T;
+      y: Constraint<T>; // ok
+    }
+
+    interface C<T> {
+              ~
+!!! error TS2428: All declarations of 'C' must have identical type parameters.
+      x: T;
+    }
+
+    interface C<T extends number> { // error
+              ~
+!!! error TS2428: All declarations of 'C' must have identical type parameters.
+      y: T;
+    }
+
+    interface Constraint<T extends number> {}
+
diff --git a/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.js b/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.js
@@ -39,6 +39,27 @@ module M3 {
     export interface A<T extends Number> { // error
         y: T;
     }
-}
+}
+
+interface B<T extends number> {
+  u: T;
+  v: Constraint<T>; // ok
+}
+
+interface B<T> { // ok
+  x: T;
+  y: Constraint<T>; // ok
+}
+
+interface C<T> {
+  x: T;
+}
+
+interface C<T extends number> { // error
+  y: T;
+}
+
+interface Constraint<T extends number> {}
+
 
 //// [twoGenericInterfacesWithDifferentConstraints.js]
diff --git a/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.symbols b/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.symbols
@@ -99,3 +99,54 @@ module M3 {
 >T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 31, 23), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 37, 23))
     }
 }
+
+interface B<T extends number> {
+>B : Symbol(B, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 40, 1), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 45, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+
+  u: T;
+>u : Symbol(B.u, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 31))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+
+  v: Constraint<T>; // ok
+>v : Symbol(B.v, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 43, 7))
+>Constraint : Symbol(Constraint, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 58, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+}
+
+interface B<T> { // ok
+>B : Symbol(B, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 40, 1), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 45, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+
+  x: T;
+>x : Symbol(B.x, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 16))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+
+  y: Constraint<T>; // ok
+>y : Symbol(B.y, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 48, 7))
+>Constraint : Symbol(Constraint, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 58, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 42, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 47, 12))
+}
+
+interface C<T> {
+>C : Symbol(C, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 50, 1), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 54, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 52, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 56, 12))
+
+  x: T;
+>x : Symbol(C.x, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 52, 16))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 52, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 56, 12))
+}
+
+interface C<T extends number> { // error
+>C : Symbol(C, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 50, 1), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 54, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 52, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 56, 12))
+
+  y: T;
+>y : Symbol(C.y, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 56, 31))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 52, 12), Decl(twoGenericInterfacesWithDifferentConstraints.ts, 56, 12))
+}
+
+interface Constraint<T extends number> {}
+>Constraint : Symbol(Constraint, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 58, 1))
+>T : Symbol(T, Decl(twoGenericInterfacesWithDifferentConstraints.ts, 60, 21))
+
diff --git a/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.types b/tests/baselines/reference/twoGenericInterfacesWithDifferentConstraints.types
@@ -99,3 +99,54 @@ module M3 {
 >T : T
     }
 }
+
+interface B<T extends number> {
+>B : B<T>
+>T : T
+
+  u: T;
+>u : T
+>T : T
+
+  v: Constraint<T>; // ok
+>v : Constraint<T>
+>Constraint : Constraint<T>
+>T : T
+}
+
+interface B<T> { // ok
+>B : B<T>
+>T : T
+
+  x: T;
+>x : T
+>T : T
+
+  y: Constraint<T>; // ok
+>y : Constraint<T>
+>Constraint : Constraint<T>
+>T : T
+}
+
+interface C<T> {
+>C : C<T>
+>T : T
+
+  x: T;
+>x : T
+>T : T
+}
+
+interface C<T extends number> { // error
+>C : C<T>
+>T : T
+
+  y: T;
+>y : T
+>T : T
+}
+
+interface Constraint<T extends number> {}
+>Constraint : Constraint<T>
+>T : T
+
diff --git a/...conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts b/...conformance/interfaces/declarationMerging/twoGenericInterfacesWithDifferentConstraints.ts
@@ -38,4 +38,24 @@ module M3 {
     export interface A<T extends Number> { // error
         y: T;
     }
-}
+}
+
+interface B<T extends number> {
+  u: T;
+  v: Constraint<T>; // ok
+}
+
+interface B<T> { // ok
+  x: T;
+  y: Constraint<T>; // ok
+}
+
+interface C<T> {
+  x: T;
+}
+
+interface C<T extends number> { // error
+  y: T;
+}
+
+interface Constraint<T extends number> {}