feat(45679): support 'did you mean' diagnostics for string literal union (#45723)

hi-ogawa · web-flow · commit 4f8aa5239ea6 · 2021-09-14T08:53:36.000-07:00
* feat(45679): support 'did you mean' diagnostics for string literal union

* Format suggested type with `typeToString`

* Address feedback
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -17831,6 +17831,13 @@ namespace ts {
                         message = Diagnostics.Type_0_is_not_assignable_to_type_1_with_exactOptionalPropertyTypes_Colon_true_Consider_adding_undefined_to_the_types_of_the_target_s_properties;
                     }
                     else {
+                        if (source.flags & TypeFlags.StringLiteral && target.flags & TypeFlags.Union) {
+                            const suggestedType = getSuggestedTypeForNonexistentStringLiteralType(source as StringLiteralType, target as UnionType);
+                            if (suggestedType) {
+                                reportError(Diagnostics.Type_0_is_not_assignable_to_type_1_Did_you_mean_2, generalizedSourceType, targetType, typeToString(suggestedType));
+                                return;
+                            }
+                        }
                         message = Diagnostics.Type_0_is_not_assignable_to_type_1;
                     }
                 }
@@ -28230,6 +28237,11 @@ namespace ts {
             return suggestion;
         }
 
+        function getSuggestedTypeForNonexistentStringLiteralType(source: StringLiteralType, target: UnionType): StringLiteralType | undefined {
+            const candidates = target.types.filter((type): type is StringLiteralType => !!(type.flags & TypeFlags.StringLiteral));
+            return getSpellingSuggestion(source.value, candidates, type => type.value);
+        }
+
         /**
          * Given a name and a list of symbols whose names are *not* equal to the name, return a spelling suggestion if there is one that is close enough.
          * Names less than length 3 only check for case-insensitive equality, not levenshtein distance.
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -3300,6 +3300,10 @@
         "category": "Error",
         "code": 2819
     },
+    "Type '{0}' is not assignable to type '{1}'. Did you mean '{2}'?": {
+        "category": "Error",
+        "code": 2820
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/tests/baselines/reference/didYouMeanStringLiteral.errors.txt b/tests/baselines/reference/didYouMeanStringLiteral.errors.txt
@@ -0,0 +1,20 @@
+tests/cases/compiler/didYouMeanStringLiteral.ts(5,7): error TS2820: Type '"strong"' is not assignable to type 'T1'. Did you mean '"string"'?
+tests/cases/compiler/didYouMeanStringLiteral.ts(6,7): error TS2322: Type '"strong"' is not assignable to type '"number" | "boolean"'.
+tests/cases/compiler/didYouMeanStringLiteral.ts(7,7): error TS2820: Type '"strong"' is not assignable to type '"string" | "boolean"'. Did you mean '"string"'?
+
+
+==== tests/cases/compiler/didYouMeanStringLiteral.ts (3 errors) ====
+    type T1 = "string" | "number" | "boolean";
+    type T2 = T1 & ("number" | "boolean"); // "number" | "boolean"
+    type T3 = T1 & ("string" | "boolean"); // "string" | "boolean"
+    
+    const t1: T1 = "strong";
+          ~~
+!!! error TS2820: Type '"strong"' is not assignable to type 'T1'. Did you mean '"string"'?
+    const t2: T2 = "strong";
+          ~~
+!!! error TS2322: Type '"strong"' is not assignable to type '"number" | "boolean"'.
+    const t3: T3 = "strong";
+          ~~
+!!! error TS2820: Type '"strong"' is not assignable to type '"string" | "boolean"'. Did you mean '"string"'?
+    
diff --git a/tests/baselines/reference/didYouMeanStringLiteral.js b/tests/baselines/reference/didYouMeanStringLiteral.js
@@ -0,0 +1,14 @@
+//// [didYouMeanStringLiteral.ts]
+type T1 = "string" | "number" | "boolean";
+type T2 = T1 & ("number" | "boolean"); // "number" | "boolean"
+type T3 = T1 & ("string" | "boolean"); // "string" | "boolean"
+
+const t1: T1 = "strong";
+const t2: T2 = "strong";
+const t3: T3 = "strong";
+
+
+//// [didYouMeanStringLiteral.js]
+var t1 = "strong";
+var t2 = "strong";
+var t3 = "strong";
diff --git a/tests/baselines/reference/didYouMeanStringLiteral.symbols b/tests/baselines/reference/didYouMeanStringLiteral.symbols
@@ -0,0 +1,24 @@
+=== tests/cases/compiler/didYouMeanStringLiteral.ts ===
+type T1 = "string" | "number" | "boolean";
+>T1 : Symbol(T1, Decl(didYouMeanStringLiteral.ts, 0, 0))
+
+type T2 = T1 & ("number" | "boolean"); // "number" | "boolean"
+>T2 : Symbol(T2, Decl(didYouMeanStringLiteral.ts, 0, 42))
+>T1 : Symbol(T1, Decl(didYouMeanStringLiteral.ts, 0, 0))
+
+type T3 = T1 & ("string" | "boolean"); // "string" | "boolean"
+>T3 : Symbol(T3, Decl(didYouMeanStringLiteral.ts, 1, 38))
+>T1 : Symbol(T1, Decl(didYouMeanStringLiteral.ts, 0, 0))
+
+const t1: T1 = "strong";
+>t1 : Symbol(t1, Decl(didYouMeanStringLiteral.ts, 4, 5))
+>T1 : Symbol(T1, Decl(didYouMeanStringLiteral.ts, 0, 0))
+
+const t2: T2 = "strong";
+>t2 : Symbol(t2, Decl(didYouMeanStringLiteral.ts, 5, 5))
+>T2 : Symbol(T2, Decl(didYouMeanStringLiteral.ts, 0, 42))
+
+const t3: T3 = "strong";
+>t3 : Symbol(t3, Decl(didYouMeanStringLiteral.ts, 6, 5))
+>T3 : Symbol(T3, Decl(didYouMeanStringLiteral.ts, 1, 38))
+
diff --git a/tests/baselines/reference/didYouMeanStringLiteral.types b/tests/baselines/reference/didYouMeanStringLiteral.types
@@ -0,0 +1,22 @@
+=== tests/cases/compiler/didYouMeanStringLiteral.ts ===
+type T1 = "string" | "number" | "boolean";
+>T1 : T1
+
+type T2 = T1 & ("number" | "boolean"); // "number" | "boolean"
+>T2 : "number" | "boolean"
+
+type T3 = T1 & ("string" | "boolean"); // "string" | "boolean"
+>T3 : "string" | "boolean"
+
+const t1: T1 = "strong";
+>t1 : T1
+>"strong" : "strong"
+
+const t2: T2 = "strong";
+>t2 : "number" | "boolean"
+>"strong" : "strong"
+
+const t3: T3 = "strong";
+>t3 : "string" | "boolean"
+>"strong" : "strong"
+
diff --git a/tests/baselines/reference/errorsForCallAndAssignmentAreSimilar.errors.txt b/tests/baselines/reference/errorsForCallAndAssignmentAreSimilar.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts(11,11): error TS2322: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'.
-tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts(16,11): error TS2322: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'.
+tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts(11,11): error TS2820: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'. Did you mean '"hddvd"'?
+tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts(16,11): error TS2820: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'. Did you mean '"hddvd"'?
 
 
 ==== tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts (2 errors) ====
@@ -15,15 +15,15 @@ tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts(16,11): error TS232
             { kind: "bluray", },
             { kind: "hdpvd", }
               ~~~~
-!!! error TS2322: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'.
+!!! error TS2820: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'. Did you mean '"hddvd"'?
 !!! related TS6500 tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts:3:13: The expected type comes from property 'kind' which is declared here on type 'Disc'
         ]);
     
         const ds: Disc[] = [
             { kind: "bluray", },
             { kind: "hdpvd", }
               ~~~~
-!!! error TS2322: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'.
+!!! error TS2820: Type '"hdpvd"' is not assignable to type '"hddvd" | "bluray"'. Did you mean '"hddvd"'?
 !!! related TS6500 tests/cases/compiler/errorsForCallAndAssignmentAreSimilar.ts:3:13: The expected type comes from property 'kind' which is declared here on type 'Disc'
         ];
     }
diff --git a/tests/cases/compiler/didYouMeanStringLiteral.ts b/tests/cases/compiler/didYouMeanStringLiteral.ts
@@ -0,0 +1,7 @@
+type T1 = "string" | "number" | "boolean";
+type T2 = T1 & ("number" | "boolean"); // "number" | "boolean"
+type T3 = T1 & ("string" | "boolean"); // "string" | "boolean"
+
+const t1: T1 = "strong";
+const t2: T2 = "strong";
+const t3: T3 = "strong";

Original file line number	Diff line number	Diff line change
`@@ -17831,6 +17831,13 @@ namespace ts {`
`17831`	`17831`	`message = Diagnostics.Type_0_is_not_assignable_to_type_1_with_exactOptionalPropertyTypes_Colon_true_Consider_adding_undefined_to_the_types_of_the_target_s_properties;`
`17832`	`17832`	`}`
`17833`	`17833`	`else {`
	`17834`	`+ if (source.flags & TypeFlags.StringLiteral && target.flags & TypeFlags.Union) {`
	`17835`	`+ const suggestedType = getSuggestedTypeForNonexistentStringLiteralType(source as StringLiteralType, target as UnionType);`
	`17836`	`+ if (suggestedType) {`
	`17837`	`+ reportError(Diagnostics.Type_0_is_not_assignable_to_type_1_Did_you_mean_2, generalizedSourceType, targetType, typeToString(suggestedType));`
	`17838`	`+ return;`
	`17839`	`+ }`
	`17840`	`+ }`
`17834`	`17841`	`message = Diagnostics.Type_0_is_not_assignable_to_type_1;`
`17835`	`17842`	`}`
`17836`	`17843`	`}`
`@@ -28230,6 +28237,11 @@ namespace ts {`
`28230`	`28237`	`return suggestion;`
`28231`	`28238`	`}`
`28232`	`28239`
	`28240`	`+ function getSuggestedTypeForNonexistentStringLiteralType(source: StringLiteralType, target: UnionType): StringLiteralType \| undefined {`
	`28241`	`+ const candidates = target.types.filter((type): type is StringLiteralType => !!(type.flags & TypeFlags.StringLiteral));`
	`28242`	`+ return getSpellingSuggestion(source.value, candidates, type => type.value);`
	`28243`	`+ }`
	`28244`	`+`
`28233`	`28245`	`/**`
`28234`	`28246`	`* Given a name and a list of symbols whose names are not equal to the name, return a spelling suggestion if there is one that is close enough.`
`28235`	`28247`	`* Names less than length 3 only check for case-insensitive equality, not levenshtein distance.`