internal/analysis/modernize: minmax: reject IfStmt with Init

Updates golang/go#71111

Change-Id: I86cdf1731e6057c4c972b91c46e8d3216a18382d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/640037
Auto-Submit: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
Commit-Queue: Alan Donovan <[email protected]>

Author: adonovan

Diff for: gopls/internal/analysis/modernize/minmax.go

@@ -84,11 +84,11 @@ func minmax(pass *analysis.Pass) {
 							// Replace IfStmt with lhs = min(a, b).
 							Pos: ifStmt.Pos(),
 							End: ifStmt.End(),
-							NewText: []byte(fmt.Sprintf("%s = %s(%s, %s)",
+							NewText: fmt.Appendf(nil, "%s = %s(%s, %s)",
 								formatNode(pass.Fset, lhs),
 								sym,
 								formatNode(pass.Fset, a),
-								formatNode(pass.Fset, b))),
+								formatNode(pass.Fset, b)),
 						}},
 					}},
 				})
@@ -133,10 +133,10 @@ func minmax(pass *analysis.Pass) {
 							// Replace rhs2 and IfStmt with min(a, b)
 							Pos: rhs2.Pos(),
 							End: ifStmt.End(),
-							NewText: []byte(fmt.Sprintf("%s(%s, %s)",
+							NewText: fmt.Appendf(nil, "%s(%s, %s)",
 								sym,
 								formatNode(pass.Fset, a),
-								formatNode(pass.Fset, b))),
+								formatNode(pass.Fset, b)),
 						}},
 					}},
 				})
@@ -151,6 +151,7 @@ func minmax(pass *analysis.Pass) {
 			ifStmt := curIfStmt.Node().(*ast.IfStmt)
 
 			if compare, ok := ifStmt.Cond.(*ast.BinaryExpr); ok &&
+				ifStmt.Init == nil &&
 				isInequality(compare.Op) != 0 &&
 				isAssignBlock(ifStmt.Body) {
 

Diff for: gopls/internal/analysis/modernize/testdata/src/minmax/minmax.go

@@ -63,3 +63,11 @@ func shadowed() int {
 	}
 	return time
 }
+
+func nopeIfStmtHasInitStmt() {
+	x := 1
+	if y := 2; y < x { // silent: IfStmt has an Init stmt
+		x = y
+	}
+	print(x)
+}

Diff for: gopls/internal/analysis/modernize/testdata/src/minmax/minmax.go.golden

@@ -43,3 +43,11 @@ func shadowed() int {
 	}
 	return time
 }
+
+func nopeIfStmtHasInitStmt() {
+	x := 1
+	if y := 2; y < x { // silent: IfStmt has an Init stmt
+		x = y
+	}
+	print(x)
+}