zclsyntax: fix parser infinite loops on certain EOF cases

The recovery functions in particular were not all properly handling EOF,
so they would spin forever looking for the right place to stop.

zcl/zclsyntax/parser.go

@@ -71,20 +71,22 @@ Token:
 			}
 		default:
 			bad := p.Read()
-			if bad.Type == TokenOQuote {
-				diags = append(diags, &zcl.Diagnostic{
-					Severity: zcl.DiagError,
-					Summary:  "Invalid attribute name",
-					Detail:   "Attribute names must not be quoted.",
-					Subject:  &bad.Range,
-				})
-			} else {
-				diags = append(diags, &zcl.Diagnostic{
-					Severity: zcl.DiagError,
-					Summary:  "Attribute or block definition required",
-					Detail:   "An attribute or block definition is required here.",
-					Subject:  &bad.Range,
-				})
+			if !p.recovery {
+				if bad.Type == TokenOQuote {
+					diags = append(diags, &zcl.Diagnostic{
+						Severity: zcl.DiagError,
+						Summary:  "Invalid attribute name",
+						Detail:   "Attribute names must not be quoted.",
+						Subject:  &bad.Range,
+					})
+				} else {
+					diags = append(diags, &zcl.Diagnostic{
+						Severity: zcl.DiagError,
+						Summary:  "Attribute or block definition required",
+						Detail:   "An attribute or block definition is required here.",
+						Subject:  &bad.Range,
+					})
+				}
 			}
 			endRange = p.PrevRange() // arbitrary, but somewhere inside the body means better diagnostics
 
@@ -169,6 +171,19 @@ Token:
 			diags = append(diags, labelDiags...)
 			labels = append(labels, label)
 			labelRanges = append(labelRanges, labelRange)
+			if labelDiags.HasErrors() {
+				p.recoverAfterBodyItem()
+				return &Block{
+					Type:   blockType,
+					Labels: labels,
+					Body:   nil,
+
+					TypeRange:       ident.Range,
+					LabelRanges:     labelRanges,
+					OpenBraceRange:  ident.Range, // placeholder
+					CloseBraceRange: ident.Range, // placeholder
+				}, diags
+			}
 
 		default:
 			switch tok.Type {
@@ -346,6 +361,8 @@ func (p *parser) recover(end TokenType) {
 			}
 
 			nest--
+		case TokenEOF:
+			return
 		}
 	}
 }
@@ -366,7 +383,7 @@ Token:
 	for {
 		tok := p.Read()
 		switch tok.Type {
-		case start:
+		case start, TokenEOF:
 			break Token
 		}
 	}