Merge pull request microsoft#29959 from Microsoft/noResolvedTypeOverwrite

Never overwrite resolved types of symbols

Author: ahejlsberg

src/compiler/checker.ts

@@ -5425,7 +5425,16 @@ namespace ts {
 
         function getTypeOfVariableOrParameterOrProperty(symbol: Symbol): Type {
             const links = getSymbolLinks(symbol);
-            return links.type || (links.type = getTypeOfVariableOrParameterOrPropertyWorker(symbol));
+            if (!links.type) {
+                const type = getTypeOfVariableOrParameterOrPropertyWorker(symbol);
+                // For a contextually typed parameter it is possible that a type has already
+                // been assigned (in assignTypeToParameterAndFixTypeParameters), and we want
+                // to preserve this type.
+                if (!links.type) {
+                    links.type = type;
+                }
+            }
+            return links.type;
         }
 
         function getTypeOfVariableOrParameterOrPropertyWorker(symbol: Symbol) {
@@ -5469,7 +5478,7 @@ namespace ts {
                 if (symbol.flags & SymbolFlags.ValueModule) {
                     return getTypeOfFuncClassEnumModule(symbol);
                 }
-                return errorType;
+                return reportCircularityError(symbol);
             }
             let type: Type | undefined;
             if (isInJSFile(declaration) &&
@@ -5528,7 +5537,7 @@ namespace ts {
                 if (symbol.flags & SymbolFlags.ValueModule) {
                     return getTypeOfFuncClassEnumModule(symbol);
                 }
-                type = reportCircularityError(symbol);
+                return reportCircularityError(symbol);
             }
             return type;
         }

tests/baselines/reference/jsFileClassSelfReferencedProperty.types

@@ -4,11 +4,11 @@ export class StackOverflowTest {
 
   constructor () {
     this.testStackOverflow = this.testStackOverflow.bind(this)
->this.testStackOverflow = this.testStackOverflow.bind(this) : error
+>this.testStackOverflow = this.testStackOverflow.bind(this) : any
 >this.testStackOverflow : any
 >this : this
 >testStackOverflow : any
->this.testStackOverflow.bind(this) : error
+>this.testStackOverflow.bind(this) : any
 >this.testStackOverflow.bind : any
 >this.testStackOverflow : any
 >this : this

tests/baselines/reference/parserES5ForOfStatement18.types

@@ -1,5 +1,5 @@
 === tests/cases/conformance/parser/ecmascript5/Statements/parserES5ForOfStatement18.ts ===
 for (var of of of) { }
 >of : any
->of : error
+>of : any
 

tests/baselines/reference/parserES5ForOfStatement19.types

@@ -1,5 +1,5 @@
 === tests/cases/conformance/parser/ecmascript5/Statements/parserES5ForOfStatement19.ts ===
 for (var of in of) { }
 >of : any
->of : error
+>of : any
 

tests/baselines/reference/parserForOfStatement18.types

@@ -1,5 +1,5 @@
 === tests/cases/conformance/parser/ecmascript6/Iterators/parserForOfStatement18.ts ===
 for (var of of of) { }
 >of : any
->of : error
+>of : any
 

tests/baselines/reference/parserForOfStatement19.types

@@ -1,5 +1,5 @@
 === tests/cases/conformance/parser/ecmascript6/Iterators/parserForOfStatement19.ts ===
 for (var of in of) { }
 >of : any
->of : error
+>of : any
 

tests/baselines/reference/recur1.types

@@ -15,7 +15,7 @@ salt.pepper = function() {}
 
 var cobalt = new cobalt.pitch();   
 >cobalt : any
->new cobalt.pitch() : error
+>new cobalt.pitch() : any
 >cobalt.pitch : any
 >cobalt : any
 >pitch : any

tests/baselines/reference/recursiveExportAssignmentAndFindAliasedType7.types

@@ -14,7 +14,7 @@ import self = require("recursiveExportAssignmentAndFindAliasedType7_moduleD");
 
 var selfVar = self;
 >selfVar : any
->self : error
+>self : any
 
 export = selfVar;
 >selfVar : any