Cherry-pick PR microsoft#54656 into release-5.1

Component commits:
1d77caa fix: no variable suggestions without semicolon

9c87f3a tests!

f67c9a3 lint

862807b make sure parameter takes priority

4c2bcc9 better formatting

src/services/completions.ts

@@ -2394,7 +2394,7 @@ export function getCompletionEntriesFromSymbols(
     includeSymbol = false
 ): UniqueNameSet {
     const start = timestamp();
-    const variableOrParameterDeclaration = getVariableOrParameterDeclaration(contextToken);
+    const variableOrParameterDeclaration = getVariableOrParameterDeclaration(contextToken, location);
     const useSemicolons = probablyUsesSemicolons(sourceFile);
     const typeChecker = program.getTypeChecker();
     // Tracks unique names.
@@ -5464,14 +5464,20 @@ function isModuleSpecifierMissingOrEmpty(specifier: ModuleReference | Expression
     return !tryCast(isExternalModuleReference(specifier) ? specifier.expression : specifier, isStringLiteralLike)?.text;
 }
 
-function getVariableOrParameterDeclaration(contextToken: Node | undefined) {
+function getVariableOrParameterDeclaration(contextToken: Node | undefined, location: Node) {
     if (!contextToken) return;
 
-    const declaration = findAncestor(contextToken, node =>
+    const possiblyParameterDeclaration = findAncestor(contextToken, node =>
         isFunctionBlock(node) || isArrowFunctionBody(node) || isBindingPattern(node)
             ? "quit"
-            : isVariableDeclaration(node) || ((isParameter(node) || isTypeParameterDeclaration(node)) && !isIndexSignatureDeclaration(node.parent)));
-    return declaration as ParameterDeclaration | TypeParameterDeclaration | VariableDeclaration | undefined;
+            : ((isParameter(node) || isTypeParameterDeclaration(node)) && !isIndexSignatureDeclaration(node.parent)));
+
+    const possiblyVariableDeclaration = findAncestor(location, node =>
+        isFunctionBlock(node) || isArrowFunctionBody(node) || isBindingPattern(node)
+            ? "quit"
+            : isVariableDeclaration(node));
+
+    return (possiblyParameterDeclaration || possiblyVariableDeclaration) as ParameterDeclaration | TypeParameterDeclaration | VariableDeclaration | undefined;
 }
 
 function isArrowFunctionBody(node: Node) {

tests/cases/fourslash/completionEntryForConst.ts

@@ -1,6 +1,12 @@
 ///<reference path="fourslash.ts" />
 
 ////const c = "s";
-/////**/
+/////*1*/
+////const d = 1
+////d/*2*/
+////const e = 1
+/////*3*/
 
-verify.completions({ marker: "", includes: { name: "c", text: 'const c: "s"', kind: "const" } });
+verify.completions({ marker: ["1"], includes: { name: "c", text: 'const c: "s"', kind: "const" } });
+verify.completions({ marker: ["2"], includes: { name: "d", text: 'const d: 1', kind: "const" } });
+verify.completions({ marker: ["3"], includes: { name: "e", text: 'const e: 1', kind: "const" } });